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Sample records for aldose reductase inhibitors

  1. Prevention of hemodynamic and vascular albumin filtration changes in diabetic rats by aldose reductase inhibitors

    International Nuclear Information System (INIS)

    This study investigated hemodynamic changes in diabetic rats and their relationship to changes in vascular albumin permeation and increased metabolism of glucose to sorbitol. The effects of 6 wk of streptozocin-induced diabetes and three structurally different inhibitors of aldose reductase were examined on (1) regional blood flow (assessed with 15-microns 85Sr-labeled microspheres) and vascular permeation by 125I-labeled bovine serum albumin (BSA) and (2) glomerular filtration rate (assessed by plasma clearance of 57Co-labeled EDTA) and urinary albumin excretion (determined by radial immunodiffusion assay). In diabetic rats, blood flow was significantly increased in ocular tissues (anterior uvea, posterior uvea, retina, and optic nerve), sciatic nerve, kidney, new granulation tissue, cecum, and brain. 125I-BSA permeation was increased in all of these tissues except brain. Glomerular filtration rate and 24-h urinary albumin excretion were increased 2- and 29-fold, respectively, in diabetic rats. All three aldose reductase inhibitors completely prevented or markedly reduced these hemodynamic and vascular filtration changes and increases in tissue sorbitol levels in the anterior uvea, posterior uvea, retina, sciatic nerve, and granulation tissue. These observations indicate that early diabetes-induced hemodynamic changes and increased vascular albumin permeation and urinary albumin excretion are aldose reductase-linked phenomena. Discordant effects of aldose reductase inhibitors on blood flow and vascular albumin permeation in some tissues suggest that increased vascular albumin permeation is not entirely attributable to hemodynamic change

  2. Epalrestat, an aldose reductase inhibitor, in diabetic neuropathy: An Indian perspective

    OpenAIRE

    Sharma S; Sharma Nalini

    2008-01-01

    Background: A number of diabetic patients with diabetic neuropathy, in India, were treated with epalrestat, an aldose reductase inhibitor. In this study, more than 2000 patients with diabetic neuropathy, who were treated with epalrestat for 3-12 months, were analyzed to assess the efficacy and the adverse reactions of the drug. Method: We analyzed the subjective symptoms (spontaneous pain, numbness, coldness and hypoesthesia) and the nerve function tests (motor nerve conduction velocity, s...

  3. Pharmacologically tested aldose reductase inhibitors isolated from plant sources—A concise report

    Institute of Scientific and Technical Information of China (English)

    D.K.Patel; R.Kumar; K.Sairam; S.Hemalatha

    2012-01-01

    Aldose reductase (AR),a cytosolic,monomeric oxidoreductase,is a key enzyme in the polyol pathway which controls the conversion of glucose to sorbitol.The accumulation of sorbitol by the activation of AR enzymes in lens,retina,and sciatic nerves leads to the cause of diabetic defects resulting in various secondary complications,viz.retinopathy,neuropathy,nephropathy and Alzheimer's disease.Thus,reduction of the polyol pathway flux by AR inhibitors could be a potential therapeutic opening in the treatment and prevention of diabetic complications.At present,the AR inhibitors belong to two different chemical classes.One is the hydantoin derivatives,such as Sorbinil,Dilantin,and Minalrestat,and the other is the carboxylic acid derivatives,such as Epalrestat,Alrestatin,and Tolrestat.However,it is known that most of these synthethic compounds have unacceptable side-effects.Well known medicinal plants like Chrysanthemum indicum,Chrysanthemum morifolium,Prunus mume,Myrcia multiflora,Centella asiatica,and Salacia reticulata,Salacia oblonga,and Salacia chinensis exhibited potent AR inhibitory activity.The present review summarizes the list of plant material,and their isolated phytoconstituents which have been tested for their AR inhibitory activity.This litreature review covers the period to 2011,and a total of 72 plants are listed.

  4. Long-term clinical effects of epalrestat, an aldose reductase inhibitor, on progression of diabetic neuropathy and other microvascular complications: multivariate epidemiological analysis based on patient background factors and severity of diabetic neuropathy

    OpenAIRE

    Hotta, N.; Kawamori, R; Fukuda, M; Shigeta, Y

    2012-01-01

    Abstract Aims The goal of the study was to evaluate the efficacy of epalrestat, an aldose reductase inhibitor, on diabetic retinopathy and diabetic nephropathy, based on analysis of the results of the Aldose Reductase Inhibitor–Diabetes Complications Trial, a 3-year multicentre comparative clinical trial of conventional therapy (control group) and epalrestat therapy (epalrestat group) in Japanese patients with mild diabetic neuropathy. Methods The subjects of the study were patients enrolled ...

  5. Anti-neuroinflammatory efficacy of the aldose reductase inhibitor FMHM via phospholipase C/protein kinase C-dependent NF-κB and MAPK pathways

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Ke-Wu [State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191 (China); Li, Jun [Modern Research Center for Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing 100029 (China); Dong, Xin; Wang, Ying-Hong; Ma, Zhi-Zhong; Jiang, Yong; Jin, Hong-Wei [State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191 (China); Tu, Peng-Fei, E-mail: pengfeitu@vip.163.com [State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191 (China); Modern Research Center for Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing 100029 (China)

    2013-11-15

    Aldose reductase (AR) has a key role in several inflammatory diseases: diabetes, cancer and cardiovascular diseases. Therefore, AR inhibition seems to be a useful strategy for anti-inflammation therapy. In the central nervous system (CNS), microglial over-activation is considered to be a central event in neuroinflammation. However, the effects of AR inhibition in CNS inflammation and its underlying mechanism of action remain unknown. In the present study, we found that FMHM (a naturally derived AR inhibitor from the roots of Polygala tricornis Gagnep.) showed potent anti-neuroinflammatory effects in vivo and in vitro by inhibiting microglial activation and expression of inflammatory mediators. Mechanistic studies showed that FMHM suppressed the activity of AR-dependent phospholipase C/protein kinase C signaling, which further resulted in downstream inactivation of the IκB kinase/IκB/nuclear factor-kappa B (NF-κB) inflammatory pathway. Therefore, AR inhibition-dependent NF-κB inactivation negatively regulated the transcription and expression of various inflammatory genes. AR inhibition by FMHM exerted neuroprotective effects in lipopolysaccharide-induced neuron–microglia co-cultures. These findings suggested that AR is a potential target for neuroinflammation inhibition and that FMHM could be an effective agent for treating or preventing neuroinflammatory diseases. - Highlights: • FMHM is a natural-derived aldose reductase (AR) inhibitor. • FMHM inhibits various neuroinflammatory mediator productions in vitro and in vivo. • FMHM inhibits neuroinflammation via aldose reductase/PLC/PKC-dependent NF-κB pathway. • FMHM inhibits neuroinflammation via aldose reductase/PLC/PKC-dependent MAPK pathway. • FMHM protects neurons against inflammatory injury in microglia-neuron co-cultures.

  6. Iodine-123-metaiodobenzylguanidine cardiac scintigraphy in patients with diabetes mellitus. Therapeutic effects of aldose reductase inhibitor and vitamin B12

    International Nuclear Information System (INIS)

    Twenty normal volunteers (C group) and 56 patients with non-insulin-dependent diabetes mellitus (NIDDM) who did not have ischemic heart diseases (DM group), were evaluated by means of iodine-123-metaiodobenzylguanidine (MIBG) scintigraphy. The uptake ratio between the cardiac muscle and the upper mediastinum was calculated. The ratio determined from the initial I-123-MIBG scintigraphy image was expressed as HMi, and that determined from the delayed image was expressed as HMd. The washout rate percentage (%WR) was calculated. At least one instance of either the HMi, the HMd, or %WR was outside the mean±1 standard deviation of C group in 34 DM group patients. Aldose reductase inhibitor (ARI) was administered to 17 of the 34 patients and Vitamin B12 (VB12) to the remaining 17 patients, for 3 to 5 months. Before and after treatment, scintigraphic studies with I-123-MIBG were carried out, and the HMi, HMd, and %WR were calculated. There were no significant differences found in FBG, HbA1c, or 1.5-AG levels after treatment with either drug, when compared to the pretreatment values. Both HMi and HMd in the DM group were significantly lower, and %WR was significantly higher than in the C group. The changes in HMi, HMd, and %WR after treatment with ARI were not significant. After treatment with VB12, the HMi and HMd levels were significantly increased (p12 was shown to be effective for improvement of HMi and HMd in NIDDM. (author)

  7. Aldose reductase mediates retinal microglia activation.

    Science.gov (United States)

    Chang, Kun-Che; Shieh, Biehuoy; Petrash, J Mark

    2016-04-29

    Retinal microglia (RMG) are one of the major immune cells in charge of surveillance of inflammatory responses in the eye. In the absence of an inflammatory stimulus, RMG reside predominately in the ganglion layer and inner or outer plexiform layers. However, under stress RMG become activated and migrate into the inner nuclear layer (INL) or outer nuclear layer (ONL). Activated RMG in cell culture secrete pro-inflammatory cytokines in a manner sensitive to downregulation by aldose reductase inhibitors. In this study, we utilized CX3CR1(GFP) mice carrying AR mutant alleles to evaluate the role of AR on RMG activation and migration in vivo. When tested on an AR(WT) background, IP injection of LPS induced RMG activation and migration into the INL and ONL. However, this phenomenon was largely prevented by AR inhibitors or in AR null mice, or was exacerbated in transgenic mice that over-express AR. LPS-induced increases in ocular levels of TNF-α and CX3CL-1 in WT mice were substantially lower in AR null mice or were reduced by AR inhibitor treatment. These studies demonstrate that AR expression in RMG may contribute to the proinflammatory phenotypes common to various eye diseases such as uveitis and diabetic retinopathy. PMID:27033597

  8. A series of pyrido[2,3-b]pyrazin-3(4H)-one derivatives as aldose reductase inhibitors with antioxidant activity.

    Science.gov (United States)

    Han, Zhongfei; Hao, Xin; Ma, Bing; Zhu, Changjin

    2016-10-01

    A series of pyrido[2,3-b]pyrazin-3(4H)-one based derivatives were designed as inhibitors of aldose reductase (ALR2), the enzyme which plays a key role in the development of diabetes complications as well as in the oxidative stress processes associated with diabetes and other pathologies. Most of the derivatives, having a substituted C2 aromatic group and a N4 acetic acid group on the core structure, were found to be potent and selective aldose reductase inhibitors with submicromolar IC50 values, and 9c was the most active with IC50 value 0.009 μM. Particularly, a number of the designed compounds bearing phenolic hydroxyl substituted C2-styryl side chain showed excellent not only in ALR2 inhibition but also in antioxidant, and among these 11i was proved to be the top one with an antioxidant ability even comparable to that of the well-known antioxidant Trolox. Structure-activity relationship and molecular docking studies highlighted the importance of phenolic hydroxyl substituents and vinyl spacer in C2 side chain of the scaffold for the construction of efficient and multifunctional ALR2 inhibitors. PMID:27267001

  9. Binding of Fidarestat Stereoisomers with Aldose Reductase

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    Dae-Sil Lee

    2006-11-01

    Full Text Available The stereospecificity in binding to aldose reductase (ALR2 of two fidarestat {6-fluoro-2',5'-dioxospiro[chroman-4,4'-imidazolidine]-2-carboxamide} stereoisomers [(2S,4Sand (2R,4S] has been investigated by means of molecular dynamics simulations using freeenergy integration techniques. The difference in the free energy of binding was found to be2.0 ± 1.7 kJ/mol in favour of the (2S,4S-form, in agreement with the experimentalinhibition data. The relative mobilities of the fidarestats complexed with ALR2 indicate alarger entropic penalty for hydrophobic binding of (2R,4S-fidarestat compared to (2S,4S-fidarestat, partially explaining its lower binding affinity. The two stereoisomers differmainly in the orientation of the carbamoyl moiety with respect to the active site and rotationof the bond joining the carbamoyl substituent to the ring. The detailed structural andenergetic insights obtained from out simulations allow for a better understanding of thefactors determining stereospecific inhibitor-ALR2 binding in the EPF charges model.

  10. In Silico Docking studies of Aldose Reductase Inhibitory activity of selected Flavonoids

    OpenAIRE

    Muthuswamy Umamaheswari; C. S. Aji; Kuppusamy Asokkumar; Thirumalaisamy Sivashanmugam; Varadharajan Subhadradevi; Puliyath Jagannath; Arumugam Madeswaran

    2012-01-01

    New drugs for the inhibition of the enzyme aldose reductase are in development and they have to be screened before being considered for preclinical and clinical evaluation. The current study deals with the evaluation of the cyclooxygenase inhibitory activity of flavonoids using in silico docking studies. In this perspective, flavonoids like Farobin-A, Gericudranin- B, Glaziovianin-A, Rutin, and Xanthotoxin were selected. Epalrestat, a known aldose reductase inhibitor was used as the standard....

  11. Human brain aldehyde reductases: relationship to succinic semialdehyde reductase and aldose reductase.

    Science.gov (United States)

    Hoffman, P L; Wermuth, B; von Wartburg, J P

    1980-08-01

    Human brain contains multiple forms of aldehyde-reducing enzymes. One major form (AR3), as previously shown, has properties that indicate its identity with NADPH-dependent aldehyde reductase isolated from brain and other organs of various species; i.e., low molecular weight, use of NADPH as the preferred cofactor, and sensitivity to inhibition by barbiturates. A second form of aldehyde reductase ("SSA reductase") specifically reduces succinic semialdehyde (SSA) to produce gamma-hydroxybutyrate. This enzyme form has a higher molecular weight than AR3, and uses NADH as well as NADPH as cofactor. SSA reductase was not inhibited by pyrazole, oxalate, or barbiturates, and the only effective inhibitor found was the flavonoid quercetine. Although AR3 can also reduce SSA, the relative specificity of SSA reductase may enhance its in vivo role. A third form of human brain aldehyde reductase, AR2, appears to be comparable to aldose reductases characterized in several species, on the basis of its activity pattern with various sugar aldehydes and its response to characteristic inhibitors and activators, as well as kinetic parameters. This enzyme is also the most active in reducing the aldehyde derivatives of biogenic amines. These studies suggest that the various forms of human brain aldehyde reductases may have specific physiological functions. PMID:6778961

  12. Isolation, modification, and aldose reductase inhibitory activity of rosmarinic acid derivatives from the roots of Salvia grandifolia.

    Science.gov (United States)

    Kang, Jie; Tang, Yanbo; Liu, Quan; Guo, Nan; Zhang, Jian; Xiao, Zhiyan; Chen, Ruoyun; Shen, Zhufang

    2016-07-01

    To find aldose reductase inhibitors, two previously unreported compounds, grandifolias H and I, and five known compounds, including rosmarinic acid and rosmarinic acid derivatives, were isolated from the roots of Salvia grandifolia. A series of rosmarinic acid derivatives was obtained from rosmarinic acid using simple synthetic methods. The aldose reductase inhibitory activity of the isolated and synthesized compounds was assessed. Seven of the tested compounds showed moderate aldose reductase inhibition (IC50=0.06-0.30μM). The structure-activity relationship of aldose reductase inhibitory activity of rosmarinic acid derivatives was discussed for the first time. This study provided useful information that will facilitate the development of aldose reductase inhibitors. PMID:27233987

  13. Three-dimensional quantitative structure-activity relationships and docking studies of some structurally diverse flavonoids and design of new aldose reductase inhibitors

    Directory of Open Access Journals (Sweden)

    Utpal Chandra De

    2015-01-01

    Full Text Available Aldose reductase (AR plays an important role in the development of several long-term diabetic complications. Inhibition of AR activities is a strategy for controlling complications arising from chronic diabetes. Several AR inhibitors have been reported in the literature. Flavonoid type compounds are shown to have significant AR inhibition. The objective of this study was to perform a computational work to get an idea about structural insight of flavonoid type compounds for developing as well as for searching new flavonoid based AR inhibitors. The data-set comprising 68 flavones along with their pIC 50 values ranging from 0.44 to 4.59 have been collected from literature. Structure of all the flavonoids were drawn in Chembiodraw Ultra 11.0, converted into corresponding three-dimensional structure, saved as mole file and then imported to maestro project table. Imported ligands were prepared using LigPrep option of maestro 9.6 version. Three-dimensional quantitative structure-activity relationships and docking studies were performed with appropriate options of maestro 9.6 version installed in HP Z820 workstation with CentOS 6.3 (Linux. A model with partial least squares factor 5, standard deviation 0.2482, R 2 = 0.9502 and variance ratio of regression 122 has been found as the best statistical model.

  14. Aldose reductase inhibitory activity and antioxidant capacity of pomegranate extracts

    OpenAIRE

    Karasu, Çimen; CUMAOĞLU, Ahmet; Gürpinar, Ali Rifat; Kartal, Murat; Kovacikova, Lucia; Milackova, Ivana; Stefek, Milan

    2012-01-01

    The pomegranate, Punica granatum L., has been the subject of current interest as a medicinal agent with wide-ranging therapeutic indications. In the present study, pomegranate ethanolic seed and hull extracts were tested, in comparison with a commercial sample, for the inhibition of aldose reductase, an enzyme involved in the etiology of diabetic complications. In vitro inhibition of rat lens aldose reductase was determined by a conventional method. Pomegranate ethanolic hull extract and comm...

  15. 醛糖还原酶抑制剂与糖尿病慢性并发症%Aldose reductase inhibitors and chronic diabetic complication

    Institute of Scientific and Technical Information of China (English)

    林锟; 鄞国书; 林少达

    2011-01-01

    高血糖使醛糖还原酶过度激活,引起组织中山梨醇积聚,与高血糖等因素共同促进糖尿病并发症的发生发展.研究显示醛糖还原酶抑制剂可抑制山梨醇途径,通过抗氧化应激和炎症、抑制细胞凋亡、改善微循环障碍和能量代谢等延缓和治疗糖尿病并发症.醛糖还原酶抑制剂依帕司他在糖尿病微血管病变如周围神经病变、自主神经病变、肾脏疾病和视网膜病变研究中有良好作用,尤其在糖尿病周围神经病变、视网膜病变治疗中有循证医学证据,为美国糖尿病学会和中国糖尿病神经病变诊治规范的推荐药物.醛糖还原酶抑制剂新药开发给糖尿病慢性并发症防治带来新希望.%Over activation of aldose reductase which leads to accumulation of sorbitol in the tissues is considered to play an important role in the genesis and development of chronic diabetic complications along with hyperglycemia. Aldose reductase inhibitor (ARI) can inhibit sorbitol pathway by decreasing unsuitable activation of oxidative stress, inflammation and apoptosis and improving microcirculation functions and energy metabolic in vivo and vitro experiments. Epalrestat, a constant ARI, provided a clinical role of preventing and treating diabetic micro-vessel complications such as perineuropathy, neuropathy and retinopathy from evident-based medicine. ARIs are recommended as treatment for perineuropathy by American Diabetes Association and by "Diabetic Neuropathy Diagnosis and Treatment Guideline in China" . ARIs will play important roles for prevention and cure of chronic diabetic complications in the future.

  16. Effects of Long-Term Treatment with Ranirestat, a Potent Aldose Reductase Inhibitor, on Diabetic Cataract and Neuropathy in Spontaneously Diabetic Torii Rats

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    Ayumi Ota

    2013-01-01

    Full Text Available We evaluated ranirestat, an aldose reductase inhibitor, in diabetic cataract and neuropathy (DN in spontaneously diabetic Torii (SDT rats compared with epalrestat, the positive control. Animals were divided into groups and treated once daily with oral ranirestat (0.1, 1.0, 10 mg/kg or epalrestat (100 mg/kg for 40 weeks, normal Sprague-Dawley rats, and untreated SDT rats. Lens opacification was scored from 0 (normal to 3 (mature cataract. The combined scores (0–6 from both lenses represented the total for each animal. DN was assessed by measuring the motor nerve conduction velocity (MNCV in the sciatic nerve. Sorbitol and fructose levels were measured in the lens and sciatic nerve 40 weeks after diabetes onset. Cataracts developed more in untreated rats than normal rats (P<0.01. Ranirestat significantly (P<0.01 inhibited rapid cataract development; epalrestat did not. Ranirestat significantly reversed the MNCV decrease (40.7 ± 0.6 m/s in SDT rats dose-dependently (P<0.01. Epalrestat also reversed the prevented MNCV decrease (P<0.05. Sorbitol levels in the sciatic nerve increased significantly in SDT rats (2.05 ± 0.10 nmol/g, which ranirestat significantly suppressed dose-dependently, (P<0.05, <0.01, and <0.01; epalrestat did not. Ranirestat prevents DN and cataract; epalrestat prevents DN only.

  17. Aldose reductase inhibitory compounds from Xanthium strumarium.

    Science.gov (United States)

    Yoon, Ha Na; Lee, Min Young; Kim, Jin-Kyu; Suh, Hong-Won; Lim, Soon Sung

    2013-09-01

    As part of our ongoing search for natural sources of therapeutic and preventive agents for diabetic complications, we evaluated the inhibitory effects of components of the fruit of Xanthium strumarium (X. strumarium) on aldose reductase (AR) and galactitol formation in rat lenses with high levels of glucose. To identify the bioactive components of X. strumarium, 7 caffeoylquinic acids and 3 phenolic compounds were isolated and their chemical structures were elucidated on the basis of spectroscopic evidence and comparison with published data. The abilities of 10 X. strumarium-derived components to counteract diabetic complications were investigated by means of inhibitory assays with rat lens AR (rAR) and recombinant human AR (rhAR). From the 10 isolated compounds, methyl-3,5-di-O-caffeoylquinate showed the most potent inhibition, with IC₅₀ values of 0.30 and 0.67 μM for rAR and rhAR, respectively. In the kinetic analyses using Lineweaver-Burk plots of 1/velocity and 1/substrate, methyl-3,5-di-O-caffeoylquinate showed competitive inhibition of rhAR. Furthermore, methyl-3,5-di-O-caffeoylquinate inhibited galactitol formation in the rat lens and in erythrocytes incubated with a high concentration of glucose, indicating that this compound may be effective in preventing diabetic complications. PMID:23604720

  18. Effects of the New Aldose Reductase Inhibitor Benzofuroxane Derivative BF-5m on High Glucose Induced Prolongation of Cardiac QT Interval and Increase of Coronary Perfusion Pressure

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    C. Di Filippo

    2016-01-01

    Full Text Available This study investigated the effects of the new aldose reductase inhibitor benzofuroxane derivative 5(6-(benzo[d]thiazol-2-ylmethoxybenzofuroxane (BF-5m on the prolongation of cardiac QT interval and increase of coronary perfusion pressure (CPP in isolated, high glucose (33.3 mM D-glucose perfused rat hearts. BF-5m was dissolved in the Krebs solution at a final concentration of 0.01 μM, 0.05 μM, and 0.1 μM. 33.3 mM D-glucose caused a prolongation of the QT interval and increase of CPP up to values of 190 ± 12 ms and 110 ± 8 mmHg with respect to the values of hearts perfused with standard Krebs solution (11.1 mM D-glucose. The QT prolongation was reduced by 10%, 32%, and 41%, respectively, for the concentration of BF-5m 0.01 μM, 0.05 μM, and 0.1 μM. Similarly, the CPP was reduced by 20% for BF-5m 0.05 μM and by 32% for BF-5m 0.1 μM. BF-5m also increased the expression levels of sirtuin 1, MnSOD, eNOS, and FOXO-1, into the heart. The beneficial actions of BF-5m were partly abolished by the pretreatment of the rats with the inhibitor of the sirtuin 1 activity EX527 (10 mg/kg/day/7 days i.p. prior to perfusion of the hearts with high glucose + BF-5m (0.1 μM. Therefore, BF-5m supplies cardioprotection from the high glucose induced QT prolongation and increase of CPP.

  19. Iodine-123-metaiodobenzylguanidine cardiac scintigraphy in patients with diabetes mellitus. Therapeutic effects of aldose reductase inhibitor and vitamin B{sub 12}

    Energy Technology Data Exchange (ETDEWEB)

    Utsunomiya, Keita [Osaka Medical Coll., Takatsuki (Japan)

    1997-12-01

    Twenty normal volunteers (C group) and 56 patients with non-insulin-dependent diabetes mellitus (NIDDM) who did not have ischemic heart diseases (DM group), were evaluated by means of iodine-123-metaiodobenzylguanidine (MIBG) scintigraphy. The uptake ratio between the cardiac muscle and the upper mediastinum was calculated. The ratio determined from the initial I-123-MIBG scintigraphy image was expressed as HMi, and that determined from the delayed image was expressed as HMd. The washout rate percentage (%WR) was calculated. At least one instance of either the HMi, the HMd, or %WR was outside the mean{+-}1 standard deviation of C group in 34 DM group patients. Aldose reductase inhibitor (ARI) was administered to 17 of the 34 patients and Vitamin B{sub 12} (VB{sub 12}) to the remaining 17 patients, for 3 to 5 months. Before and after treatment, scintigraphic studies with I-123-MIBG were carried out, and the HMi, HMd, and %WR were calculated. There were no significant differences found in FBG, HbA1c, or 1.5-AG levels after treatment with either drug, when compared to the pretreatment values. Both HMi and HMd in the DM group were significantly lower, and %WR was significantly higher than in the C group. The changes in HMi, HMd, and %WR after treatment with ARI were not significant. After treatment with VB{sub 12}, the HMi and HMd levels were significantly increased (p<0.01). Thus, measurement of myocardial MIBG accumulation is a promising new method to detect cardiac sympathetic denervation in diabetic patients. With these changes in treatment, VB{sub 12} was shown to be effective for improvement of HMi and HMd in NIDDM. (author)

  20. Effects of aldose reductase inhibitor and vitamin B{sub 12} on myocardial uptake of iodine-123 metaiodobenzylguanidine in patients with non-insulin-dependent diabetes mellitus

    Energy Technology Data Exchange (ETDEWEB)

    Utsunomiya, Keita; Narabayashi, Isamu [Department of Radiology, Osaka Medical College, Osaka (Japan); Tamura, Koji; Nakatani, Yuko; Saika, Yoshinori; Onishi, Satoshi; Kariyone, Shigeo [Department of Radiology, Internal Medicine and Surgery, Keihanna Hospital, Osaka (Japan)

    1998-12-01

    This study was undertaken to examine the effects of aldose reductase inhibitor (ARI) and vitamin B{sub 12} (VB12) on myocardial uptake of iodine-123 metaiodobenzylguanidine (MIBG) in patients with diabetic autonomic disorder. Myocardial scintigraphy using {sup 123}I-MIBG was performed on 20 healthy volunteers (controls) and 56 patients with non-insulin-dependent diabetes mellitus (NIDDM), in order to obtain the heart/mediastinum ratio in the initial (HMi) and the delayed images (HMd), and the washout rate (%WR). Thirty-four of the 56 NIDDM patients could be diagnosed as having diabetic autonomic disorder by evaluating their scintigraphic findings in comparison with the controls. Seventeen of these 34 patients received 150 mg/day of epalrestat (ARI group) in three divided doses before meals, and the other 17 received 1.5 mg/day of mecobalamin (VB12 group) in three divided doses after meals, for 3-5 months. According to the presence or absence of clinical symptoms of autonomic or peripheral somatic nerve disorder, the patients were subclassified into four groups. group 1=patients, with autonomic symptoms or somatosensory disorder in the ARI group; group 2=patients without autonomic symptoms or somatosensory disorder in the ARI group; group 3=patients with autonomic symptoms or somatosensory disorder in the VB12 group; and group 4=patients without autonomic symptoms or somatosensory disorder in the VB12 group. After completion of the treatment, myocardial scintigraphy was performed again. Comparing the results obtained before and after the treatment, it was seen that ARI improved only the HMi in group 1 (P=0.046), whereas VB12 significantly improved HMi in the group 3 (P=0.018) and HMi, HMd and %WR in group 4 (P=0.043, P=0.018 and P=0.043, respectively). We conclude that VB12 is more efficacious than ARI in the treatment of diabetic cardiovascular autonomic disorder. (orig.) With 2 figs., 3 tabs., 23 refs.

  1. Effects of aldose reductase inhibitor and vitamin B12 on myocardial uptake of iodine-123 metaiodobenzylguanidine in patients with non-insulin-dependent diabetes mellitus

    International Nuclear Information System (INIS)

    This study was undertaken to examine the effects of aldose reductase inhibitor (ARI) and vitamin B12 (VB12) on myocardial uptake of iodine-123 metaiodobenzylguanidine (MIBG) in patients with diabetic autonomic disorder. Myocardial scintigraphy using 123I-MIBG was performed on 20 healthy volunteers (controls) and 56 patients with non-insulin-dependent diabetes mellitus (NIDDM), in order to obtain the heart/mediastinum ratio in the initial (HMi) and the delayed images (HMd), and the washout rate (%WR). Thirty-four of the 56 NIDDM patients could be diagnosed as having diabetic autonomic disorder by evaluating their scintigraphic findings in comparison with the controls. Seventeen of these 34 patients received 150 mg/day of epalrestat (ARI group) in three divided doses before meals, and the other 17 received 1.5 mg/day of mecobalamin (VB12 group) in three divided doses after meals, for 3-5 months. According to the presence or absence of clinical symptoms of autonomic or peripheral somatic nerve disorder, the patients were subclassified into four groups. group 1=patients, with autonomic symptoms or somatosensory disorder in the ARI group; group 2=patients without autonomic symptoms or somatosensory disorder in the ARI group; group 3=patients with autonomic symptoms or somatosensory disorder in the VB12 group; and group 4=patients without autonomic symptoms or somatosensory disorder in the VB12 group. After completion of the treatment, myocardial scintigraphy was performed again. Comparing the results obtained before and after the treatment, it was seen that ARI improved only the HMi in group 1 (P=0.046), whereas VB12 significantly improved HMi in the group 3 (P=0.018) and HMi, HMd and %WR in group 4 (P=0.043, P=0.018 and P=0.043, respectively). We conclude that VB12 is more efficacious than ARI in the treatment of diabetic cardiovascular autonomic disorder. (orig.)

  2. In Silico Docking studies of Aldose Reductase Inhibitory activity of selected Flavonoids

    Directory of Open Access Journals (Sweden)

    Muthuswamy Umamaheswari

    2012-09-01

    Full Text Available New drugs for the inhibition of the enzyme aldose reductase are in development and they have to be screened before being considered for preclinical and clinical evaluation. The current study deals with the evaluation of the cyclooxygenase inhibitory activity of flavonoids using in silico docking studies. In this perspective, flavonoids like Farobin-A, Gericudranin- B, Glaziovianin-A, Rutin, and Xanthotoxin were selected. Epalrestat, a known aldose reductase inhibitor was used as the standard. Docking results showed that all the selected flavonoids showed binding energy ranging between -7.91 kcal/mol to - 5.08 kcal/mol when compared with that of the standard (-5.59 kcal/mol. Intermolecular energy (- 9.11 kcal/mol to -8.66 kcal/mol and inhibition constant (1.58 μM to 187.37 μM of the ligands also coincide with the binding energy. Xanthotoxin contributed better aldose reductase inhibitory activity because of its structural parameters. Further studies are required to develop potent aldose reductase inhibitors for the treatment of diabetes.

  3. Aldose reductase inhibition improves nerve conduction velocity in diabetic patients.

    Science.gov (United States)

    Judzewitsch, R G; Jaspan, J B; Polonsky, K S; Weinberg, C R; Halter, J B; Halar, E; Pfeifer, M A; Vukadinovic, C; Bernstein, L; Schneider, M; Liang, K Y; Gabbay, K H; Rubenstein, A H; Porte, D

    1983-01-20

    To assess the potential role of polyol-pathway activity in diabetic neuropathy, we measured the effects of sorbinil--a potent inhibitor of the key polyol-pathway enzyme aldose reductase--on nerve conduction velocity in 39 stable diabetics in a randomized, double-blind, cross-over trial. During nine weeks of treatment with sorbinil (250 mg per day), nerve conduction velocity was greater than during a nine-week placebo period for all three nerves tested: the peroneal motor nerve (mean increase [+/- S.E.M.], 0.70 +/- 0.24 m per second, P less than 0.008), the median motor nerve (mean increase, 0.66 +/- 0.27, P less than 0.005), and the median sensory nerve (mean increase, 1.16 +/- 0.50, P less than 0.035). Conduction velocity for all three nerves declined significantly within three weeks after cessation of the drug. These effects of sorbinil were not related to glycemic control, which was constant during the study. Although the effect of sorbinil in improving nerve conduction velocity in diabetics was small, the findings suggest that polyol-pathway activity contributes to slowed nerve conduction in diabetics. The clinical applicability of these observations remains to be determined, but they encourage further exploration of this approach to the treatment or prevention of diabetic neuropathy. PMID:6401351

  4. Rapid Identification of Aldose Reductase Inhibitory Compounds from Perilla frutescens

    OpenAIRE

    Soon Sung Lim; Ji Hun Paek; Kuk Hyun Shin; Young-Hee Kang; Jae-Yong Lee

    2013-01-01

    The ethyl acetate (EtOAc) soluble fraction of methanol extracts of Perilla frutescens (P. frutescens) inhibits aldose reductase (AR), the key enzyme in the polyol pathway. Our investigation of inhibitory compounds from the EtOAc soluble fraction of P. frutescens was followed by identification of the inhibitory compounds by a combination of HPLC microfractionation and a 96-well enzyme assay. This allowed the biological activities to be efficiently matched with selected HPLC peaks. Structural a...

  5. Aldose Reductase Inhibitory Activity of Compounds from  Zea mays L.

    Directory of Open Access Journals (Sweden)

    Tae Hyeon Kim

    2013-01-01

    Full Text Available Aldose reductase (AR inhibitors have a considerable therapeutic potential against diabetes complications and do not increase the risk of hypoglycemia. Through bioassay-guided fractionation of an EtOH extract of the kernel from purple corn (Zea mays L., 7 nonanthocyanin phenolic compounds (compound 1–7 and 5 anthocyanins (compound 8–12 were isolated. These compounds were investigated by rat lens aldose reductase (RLAR inhibitory assays. Kinetic analyses of recombinant human aldose reductase (rhAR were performed, and intracellular galactitol levels were measured. Hirsutrin, one of 12 isolated compounds, showed the most potent RLAR inhibitory activity (IC50, 4.78 μM. In the kinetic analyses using Lineweaver-Burk plots of 1/velocity and 1/substrate concentration, hirsutrin showed competitive inhibition against rhAR. Furthermore, hirsutrin inhibited galactitol formation in rat lens and erythrocytes sample incubated with a high concentration of galactose; this finding indicates that hirsutrin may effectively prevent osmotic stress in hyperglycemia. Therefore, hirsutrin derived from Zea mays L. may be a potential therapeutic agent against diabetes complications.

  6. Autoimmunity in Membranous Nephropathy Targets Aldose Reductase and SOD2

    OpenAIRE

    Prunotto, Marco; Carnevali, Maria Luisa; Candiano, Giovanni; Murtas, Corrado; Bruschi, Maurizio; Corradini, Emilia; Trivelli, Antonella; Magnasco, Alberto; Petretto, Andrea; Santucci, Laura; Mattei, Silvia; Gatti, Rita; Scolari, Francesco; Kador, Peter; Allegri, Landino

    2010-01-01

    Glomerular targets of autoimmunity in human membranous nephropathy are poorly understood. Here, we used a combined proteomic approach to identify specific antibodies against podocyte proteins in both serum and glomeruli of patients with membranous nephropathy (MN). We detected specific anti–aldose reductase (AR) and anti–manganese superoxide dismutase (SOD2) IgG4 in sera of patients with MN. We also eluted high titers of anti-AR and anti-SOD2 IgG4 from microdissected glomeruli of three biopsi...

  7. Aldose reductase inhibition prevents metaplasia of airway epithelial cells.

    Directory of Open Access Journals (Sweden)

    Umesh C S Yadav

    Full Text Available BACKGROUND: Goblet cell metaplasia that causes mucus hypersecretion and obstruction in the airway lumen could be life threatening in asthma and chronic obstructive pulmonary disease patients. Inflammatory cytokines such as IL-13 mediate the transformation of airway ciliary epithelial cells to mucin-secreting goblet cells in acute as well as chronic airway inflammatory diseases. However, no effective and specific pharmacologic treatment is currently available. Here, we investigated the mechanisms by which aldose reductase (AR regulates the mucus cell metaplasia in vitro and in vivo. METHODOLOGY/FINDINGS: Metaplasia in primary human small airway epithelial cells (SAEC was induced by a Th2 cytokine, IL-13, without or with AR inhibitor, fidarestat. After 48 h of incubation with IL-13 a large number of SAEC were transformed into goblet cells as determined by periodic acid-schiff (PAS-staining and immunohistochemistry using antibodies against Mucin5AC. Further, IL-13 significantly increased the expression of Mucin5AC at mRNA and protein levels. These changes were significantly prevented by treatment of the SAEC with AR inhibitor. AR inhibition also decreased IL-13-induced expression of Muc5AC, Muc5B, and SPDEF, and phosphorylation of JAK-1, ERK1/2 and STAT-6. In a mouse model of ragweed pollen extract (RWE-induced allergic asthma treatment with fidarestat prevented the expression of IL-13, phosphorylation of STAT-6 and transformation of epithelial cells to goblet cells in the lung. Additionally, while the AR-null mice were resistant, wild-type mice showed goblet cell metaplasia after challenge with RWE. CONCLUSIONS: The results show that exposure of SAEC to IL-13 caused goblet cell metaplasia, which was significantly prevented by AR inhibition. Administration of fidarestat to mice prevented RWE-induced goblet cell metaplasia and AR null mice were largely resistant to allergen induced changes in the lung. Thus our results indicate that AR inhibitors

  8. Virtual screening of plant derived compounds for aldose reductase inhibition using molecular docking.

    Science.gov (United States)

    Muppalaneni, Naresh Babu; Rao, Allam Appa

    2012-01-01

    The role of the aldose reductase in type 2 diabetes is widely described. Therefore, it is of interest to identify plant derived compounds to inhibit its activity. We studied the protein-ligand interaction of 267 compounds from different parts of seven plants (Allium sativum, Coriandrum sativum, Dacus carota, Murrayyakoneigii, Eucalyptus, Calendula officinalis and Lycopersicon esculentum) with aldose reductase as the target protein. Molecular docking and re-scoring of top ten compounds (using GOLD, AutoDock Vina, eHiTS, PatchDock and MEDock) followed by rank-sum technique identified compound allium38 with high binding affinity for aldose reductase. PMID:23275691

  9. INHIBITORY ACTIVITY OF FLAVONOIDS ON THE LENS ALDOSE REDUCTASE OF HEALTHY AND DIABETIC RATS

    OpenAIRE

    M.T. Goodarzi; Zal, F; M. Malakooti; M. R. Safari S. Sadeghian

    2006-01-01

    Aldose reductase is a critical enzyme in the polyol pathway that plays an important role in diabetes mellitus. Inhibition of the activity of this enzyme can prevent cataract in diabetic patients’lenses. In this study the inhibitory effect of two flavonoids, quercetin and naringin, in the activity of aldose reductase in streptozotocin-induced diabetic and healthy rats were investigated. Thirty male rats were divided in six groups. The first, second and third group were healthy rats that receiv...

  10. Virtual screening of plant derived compounds for aldose reductase inhibition using molecular docking

    OpenAIRE

    Muppalaneni, Naresh Babu; Rao, Allam Appa

    2012-01-01

    The role of the aldose reductase in type 2 diabetes is widely described. Therefore, it is of interest to identify plant derived compounds to inhibit its activity. We studied the protein-ligand interaction of 267 compounds from different parts of seven plants (Allium sativum, Coriandrum sativum, Dacus carota, Murrayyakoneigii, Eucalyptus, Calendula officinalis and Lycopersicon esculentum) with aldose reductase as the target protein. Molecular docking and re-scoring of top ten compounds (using ...

  11. Phytochemical analysis with the antioxidant and aldose reductase inhibitory capacities of Tephrosia humilis aerial parts' extracts.

    Science.gov (United States)

    Plioukas, Michael; Gabrieli, Chrysi; Lazari, Diamanto; Kokkalou, Eugene

    2016-06-01

    The aerial parts of Tephrosia humilis were tested about their antioxidant potential, their ability to inhibit the aldose/aldehyde reductase enzymes and their phenolic content. The plant material was exhaustively extracted with petroleum ether, dichloromethane and methanol, consecutively. The concentrated methanol extract was re-extracted, successively, with diethyl ether, ethyl acetate and n-butanol. All extracts showed significant antioxidant capacity, but the most effective was the ethyl acetate extract. As about the aldose reductase inhibition, all fractions, except the aqueous, were strong inhibitors of the enzyme, with the n-butanolic and ethyl acetate fractions to inhibit the enzyme above 75%. These findings provide support to the ethnopharmacological usage of the plant as antioxidant and validate its potential to act against the long-term diabetic complications. The phytochemical analysis showed the presence of 1,4-dihydroxy-3,4-(epoxyethano)-5-cyclohexene(1), cleroindicin E(2), lupeol(3), methyl p-coumarate(4), methyl 4-hydroxybenzoate(5), prunin(6), 5,7,2',5'-tetrahydroxyflavanone 7-rutinoside(7), protocatechuic acid(8), luteolin 7-glucoside(9), apigenin(10), naringin(11), rhoifolin(12) and luteolin 7-glucuronate(13). PMID:26209262

  12. Rapid identification of aldose reductase inhibitory compounds from Perilla frutescens.

    Science.gov (United States)

    Paek, Ji Hun; Shin, Kuk Hyun; Kang, Young-Hee; Lee, Jae-Yong; Lim, Soon Sung

    2013-01-01

    The ethyl acetate (EtOAc) soluble fraction of methanol extracts of Perilla frutescens (P. frutescens) inhibits aldose reductase (AR), the key enzyme in the polyol pathway. Our investigation of inhibitory compounds from the EtOAc soluble fraction of P. frutescens was followed by identification of the inhibitory compounds by a combination of HPLC microfractionation and a 96-well enzyme assay. This allowed the biological activities to be efficiently matched with selected HPLC peaks. Structural analyses of the active compounds were performed by LC-MS(n). The main AR inhibiting compounds were tentatively identified as chlorogenic acid and rosmarinic acid by LC-MS(n). A two-step high speed counter current chromatography (HSCCC) isolation method was developed with a solvent system of n-hexane-ethyl acetate-methanol-water at 1.5:5:1:5, v/v and 3:7:5:5, v/v. The chemical structures of the isolated compounds were determined by (1)H- and (13)C-nuclear magnetic resonance spectrometry (NMR). The main compounds inhibiting AR in the EtOAc fraction of methanol extracts of P. frutescens were identified as chlorogenic acid (2) (IC50 = 3.16 μ M), rosmarinic acid (4) (IC50 = 2.77 μ M), luteolin (5) (IC50 = 6.34 μ M), and methyl rosmarinic acid (6) (IC50 = 4.03 μ M). PMID:24308003

  13. INHIBITORY ACTIVITY OF FLAVONOIDS ON THE LENS ALDOSE REDUCTASE OF HEALTHY AND DIABETIC RATS

    Directory of Open Access Journals (Sweden)

    M. T. Goodarzi

    2006-05-01

    Full Text Available Aldose reductase is a critical enzyme in the polyol pathway that plays an important role in diabetes mellitus. Inhibition of the activity of this enzyme can prevent cataract in diabetic patients’lenses. In this study the inhibitory effect of two flavonoids, quercetin and naringin, in the activity of aldose reductase in streptozotocin-induced diabetic and healthy rats were investigated. Thirty male rats were divided in six groups. The first, second and third group were healthy rats that received water,quercetin and naringin, respectively. The fourth, fifth and sixth groups were streptozocin-induced diabetic rats that received water, quercetin and naringin, respectively. These rats were fed orally in a definite dose from each substance for 12 days. After this period rats were scarified and their lenses were separated and homogenized. The activity of aldose reductase was measured in each homogenized sample separately. The effect of feeding of these substances in blood sugar was also determined. Aldose reductase activity was reduced 73 and 69 percent in diabetic rats fed by quercetin and naringin, respectively, and the difference compared to control group was significant. In healthy rats this reduction was 63 and 59 percent, respectively, and the difference was significant compared to those who did not receive flavonoids. It was concluded that these substances were effective in reduction of aldose reductase activity in vivo and consequently could delay the progress of cataract.

  14. Affinity purifications of aldose reductase and xylitol dehydrogenase from the xylose-fermenting yeast Pachysolen tannophilus

    Energy Technology Data Exchange (ETDEWEB)

    Bolen, P.L.; Roth, K.A.; Freer, S.N.

    1986-10-01

    Although xylose is a major product of hydrolysis of lignocellulosic materials, few yeasts are able to convert it to ethanol. In Pachysolen tannophilus, one of the few xylose-fermenting yeasts found, aldose reductase and xylitol dehydrogenase were found to be key enzymes in the metabolic pathway for xylose fermentation. This paper presents a method for the rapid and simultaneous purification of both aldose reductase and xylitol dehydrogenase from P. tannophilus. Preliminary studies indicate that this method may be easily adapted to purify similar enzymes from other xylose-fermenting yeasts.

  15. NADPH-dependent D-aldose reductases and xylose fermentation in Fusarium oxysporum

    DEFF Research Database (Denmark)

    Panagiotou, Gianni; Christakopoulos, P.

    2004-01-01

    Two aldose (xylose) reductases (ARI and ARII) from Fusarium oxysporum were purified and characterized. The native ARI was a monomer with M-r 41000, pI 5.2 and showed a 52-fold preference for NADPH over NADH, while ARII was homodimeric with a subunit of M-r 37000, pI 3.6 and a 60-fold preference...

  16. Crystallization and preliminary X-ray diffraction analysis of maize aldose reductase

    Energy Technology Data Exchange (ETDEWEB)

    Kiyota, Eduardo [Laboratório de Biologia Estrutural, Instituto de Química, Universidade Estadual de Campinas, CP 6154, 13083-970 Campinas-SP (Brazil); Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas-SP (Brazil); Sousa, Sylvia Morais de [Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas-SP (Brazil); Santos, Marcelo Leite dos; Costa Lima, Aline da [Laboratório de Biologia Estrutural, Instituto de Química, Universidade Estadual de Campinas, CP 6154, 13083-970 Campinas-SP (Brazil); Menossi, Marcelo [Departamento de Genética e Evolução, Instituto de Biologia, Universidade Estadual de Campinas, Campinas-SP (Brazil); Yunes, José Andrés [Laboratório de Biologia Molecular, Centro Infantil Boldrini, Campinas-SP (Brazil); Aparicio, Ricardo, E-mail: aparicio@iqm.unicamp.br [Laboratório de Biologia Estrutural, Instituto de Química, Universidade Estadual de Campinas, CP 6154, 13083-970 Campinas-SP (Brazil)

    2007-11-01

    Preliminary X-ray diffraction studies of apo maize aldose reductase at 2.0 Å resolution are reported. Maize aldose reductase (AR) is a member of the aldo-keto reductase superfamily. In contrast to human AR, maize AR seems to prefer the conversion of sorbitol into glucose. The apoenzyme was crystallized in space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 47.2, b = 54.5, c = 100.6 Å and one molecule in the asymmetric unit. Synchrotron X-ray diffraction data were collected and a final resolution limit of 2.0 Å was obtained after data reduction. Phasing was carried out by an automated molecular-replacement procedure and structural refinement is currently in progress. The refined structure is expected to shed light on the functional/enzymatic mechanism and the unusual activities of maize AR.

  17. Crystallization and preliminary X-ray diffraction analysis of maize aldose reductase

    International Nuclear Information System (INIS)

    Preliminary X-ray diffraction studies of apo maize aldose reductase at 2.0 Å resolution are reported. Maize aldose reductase (AR) is a member of the aldo-keto reductase superfamily. In contrast to human AR, maize AR seems to prefer the conversion of sorbitol into glucose. The apoenzyme was crystallized in space group P212121, with unit-cell parameters a = 47.2, b = 54.5, c = 100.6 Å and one molecule in the asymmetric unit. Synchrotron X-ray diffraction data were collected and a final resolution limit of 2.0 Å was obtained after data reduction. Phasing was carried out by an automated molecular-replacement procedure and structural refinement is currently in progress. The refined structure is expected to shed light on the functional/enzymatic mechanism and the unusual activities of maize AR

  18. Aldose reductase regulates acrolein-induced cytotoxicity in human small airway epithelial cells

    OpenAIRE

    Yadav, Umesh CS; Ramana, KV; Srivastava, SK

    2013-01-01

    Aldose reductase (AR), a glucose metabolizing enzyme, reduces lipid aldehydes and their glutathione conjugates with more than 1000-fold efficiency (Km aldehydes 5-30μM) than glucose. Acrolein, a major endogenous lipid peroxidation product as well as component of environmental pollutant and cigarette smoke, is known to be involved in various pathologies including atherosclerosis, airway inflammation, COPD, and age-related disorders but the mechanism of acrolein-induced cytotoxicity is not clea...

  19. Inhibition of aldose reductase by herbs extracts and natural substances and their role in prevention of cataracts Inhibición de la aldolasa reductasa por extractos de plantas y sustancias naturales y su papel en la prevención de las cataratas

    OpenAIRE

    Ángel Guzmán; Ricardo O Guerrero

    2005-01-01

    Cataractogenesis is a common complication that occurs in diabetes mellitus. Aldose reductase is a lens enzyme probably involved in the development of this eye problem. The purpose of this investigation was to screen plant extracts for aldose reductase inhibitors (ARI) and to investigate their possible influence in diabetic cataractogenesis prevention. 13 plants and 3 natural products were randomly selected for our experiment. The 19 extracts originated from plant material which was extracted ...

  20. High-resolution neutron protein crystallography with radically small crystal volumes: Application of perdeuteration to human aldose reductase

    International Nuclear Information System (INIS)

    Neutron diffraction data have been collected to 2.2 (angstrom) resolution from a small (0.15 mm3) crystal of perdeuterated human aldose reductase (h-AR; MW = 36 kDa) in order to help to determine the protonation state of the enzyme. h-AR belongs to the aldo-keto reductase family and is implicated in diabetic complications. Its ternary complexes (h-AR-coenzyme NADPH-selected inhibitor) provide a good model to study both the enzymatic mechanism and inhibition. Here, the successful production of fully deuterated human aldose reductase (h-AR(D)), subsequent crystallization of the ternary complex h-AR(D)-NADPH-IDD594 and neutron Laue data collection at the LADI instrument at ILL using a crystal volume of just 0.15 mm3 are reported. Neutron data were recorded to 2 (angstrom) resolution, with subsequent data analysis using data to 2.2 (angstrom). This is the first fully deuterated enzyme of this size (36 kDa) to be solved by neutron diffraction and represents a milestone in the field, as the crystal volume is at least one order of magnitude smaller than those usually required for other high-resolution neutron structures determined to date. This illustrates the significant increase in the signal-to-noise ratio of data collected from perdeuterated crystals and demonstrates that good-quality neutron data can now be collected from more typical protein crystal volumes. Indeed, the signal-to-noise ratio is then dominated by other sources of instrument background, the nature of which is under investigation. This is important for the design of future instruments, which should take maximum advantage of the reduction in the intrinsic diffraction pattern background from fully deuterated samples.

  1. Inhibition of aldose reductase prevents experimental allergic airway inflammation in mice.

    Directory of Open Access Journals (Sweden)

    Umesh C S Yadav

    Full Text Available BACKGROUND: The bronchial asthma, a clinical complication of persistent inflammation of the airway and subsequent airway hyper-responsiveness, is a leading cause of morbidity and mortality in critically ill patients. Several studies have shown that oxidative stress plays a key role in initiation as well as amplification of inflammation in airways. However, still there are no good anti-oxidant strategies available for therapeutic intervention in asthma pathogenesis. Most recent studies suggest that polyol pathway enzyme, aldose reductase (AR, contributes to the pathogenesis of oxidative stress-induced inflammation by affecting the NF-kappaB-dependent expression of cytokines and chemokines and therefore inhibitors of AR could be anti-inflammatory. Since inhibitors of AR have already gone through phase-III clinical studies for diabetic complications and found to be safe, our hypothesis is that AR inhibitors could be novel therapeutic drugs for the prevention and treatment of asthma. Hence, we investigated the efficacy of AR inhibition in the prevention of allergic responses to a common natural airborne allergen, ragweed pollen that leads to airway inflammation and hyper-responsiveness in a murine model of asthma. METHODS AND FINDINGS: Primary Human Small Airway Epithelial Cells (SAEC were used to investigate the in vitro effects of AR inhibition on ragweed pollen extract (RWE-induced cytotoxic and inflammatory signals. Our results indicate that inhibition of AR prevents RWE -induced apoptotic cell death as measured by annexin-v staining, increase in the activation of NF-kappaB and expression of inflammatory markers such as inducible nitric oxide synthase (iNOS, cycloxygenase (COX-2, Prostaglandin (PG E(2, IL-6 and IL-8. Further, BALB/c mice were sensitized with endotoxin-free RWE in the absence and presence of AR inhibitor and followed by evaluation of perivascular and peribronchial inflammation, mucin production, eosinophils infiltration and

  2. Aldose reductase deficiency in mice protects from ragweed pollen extract (RWE-induced allergic asthma

    Directory of Open Access Journals (Sweden)

    Yadav Umesh CS

    2011-11-01

    Full Text Available Abstract Background Childhood hospitalization related to asthma remains at historically high levels, and its incidence is on the rise world-wide. Previously, we have demonstrated that aldose reductase (AR, a regulatory enzyme of polyol pathway, is a major mediator of allergen-induced asthma pathogenesis in mouse models. Here, using AR null (AR-/- mice we have investigated the effect of AR deficiency on the pathogenesis of ragweed pollen extract (RWE-induced allergic asthma in mice and also examined the efficacy of enteral administration of highly specific AR inhibitor, fidarestat. Methods The wild type (WT and AR-/- mice were sensitized and challenged with RWE to induce allergic asthma. AR inhibitor, fidarestat was administered orally. Airway hyper-responsiveness was measured in unrestrained animals using whole body plethysmography. Mucin levels and Th2 cytokine in broncho-alveolar lavage (BAL were determined using mouse anti-Muc5A/C ELISA kit and multiplex cytokine array, respectively. Eosinophils infiltration and goblet cells were assessed by H&E and periodic acid Schiff (PAS-staining of formalin-fixed, paraffin-embedded lung sections. T regulatory cells were assessed in spleen derived CD4+CD25+ T cells population. Results Deficiency of AR in mice led to significantly decreased PENH, a marker of airway hyper-responsiveness, metaplasia of airway epithelial cells and mucus hyper-secretion following RWE-challenge. This was accompanied by a dramatic decrease in infiltration of eosinophils into sub-epithelium of lung as well as in BAL and release of Th2 cytokines in response to RWE-challenge of AR-/- mice. Further, enteral administration of fidarestat significantly prevented eosinophils infiltration, airway hyper-responsiveness and also markedly increased population of T regulatory (CD4+CD25+FoxP3+ cells as compared to RWE-sensitized and challenged mice not treated with fidarestat. Conclusion Our results using AR-/- mice strongly suggest the role

  3. Scopoletin Inhibits Rat Aldose Reductase Activity and Cataractogenesis in Galactose-Fed Rats

    Directory of Open Access Journals (Sweden)

    Junghyun Kim

    2013-01-01

    Full Text Available Cataracts are a major cause of human blindness. Aldose reductase (AR is an important rate-limiting enzyme that contributes to cataract induction in diabetic patients. Scopoletin is the main bioactive constituent of flower buds from Magnolia fargesii and is known to inhibit AR activity. To assess scopoletin’s ability to mitigate sugar cataract formation in vivo, we studied its effects in a rat model of dietary galactose-induced sugar cataracts. Galactose-fed rats were orally dosed with scopoletin (10 or 50 mg/kg body weight once a day for 2 weeks. Administering scopoletin delayed the progression of the cataracts that were induced by dietary galactose. Scopoletin also prevented galactose-induced changes in lens morphology, such as lens fiber swelling and membrane rupture. Scopoletin’s protective effect against sugar cataracts was mediated by inhibiting both AR activity and oxidative stress. These results suggest that scopoletin is a useful treatment for sugar cataracts.

  4. Triple aldose reductase/α-glucosidase/radical scavenging high-resolution profiling combined with high-performance liquid chromatography – high-resolution mass spectrometry – solid-phase extraction – nuclear magnetic resonance spectroscopy for identification of antidiabetic constituents in crude

    DEFF Research Database (Denmark)

    Tahtah, Yousof; Kongstad, Kenneth Thermann; Wubshet, Sileshi Gizachew;

    2015-01-01

    /α-glucosidase/radical scavenging high-resolution inhibition profile - allowing proof of concept with Radix Scutellariae crude extract as a polypharmacological herbal drug. The triple bioactivity high-resolution profiles were used to pinpoint bioactive compounds, and subsequent structure elucidation was performed with hyphenated...... high-performance liquid chromatography – high-resolution mass spectrometry – solid-phase extraction – nuclear magnetic resonance spectroscopy. The only α-glucosidase inhibitor was baicalein, whereas main aldose reductase inhibitors in the crude extract were baicalein and skullcapflavone II, and main......In this work, development of a new microplate-based high-resolution profiling assay using recombinant human aldose reductase is presented. Used together with high-resolution radical scavenging and high-resolution α-glucosidase assays, it provided the first report of a triple aldose reductase...

  5. Self-organizing maps and VolSurf approach to predict aldose reductase inhibition by flavonoid compounds

    Directory of Open Access Journals (Sweden)

    Luciana Scotti

    2011-02-01

    Full Text Available Aldose Reductase (AR is the polyol pathway key enzyme which converts glucose to sorbitol. High glucose availability in insulin resistant tissues in diabetes leads into an accumulation of sorbitol, which has been associated with typical chronic complications of this disease, such as neuropathy, nephropathy and retinopathy. In this study, 71 flavonoids AR inhibitors were subjected to two methods of SAR to verify crucial substituents. The first method used the PCA (Principal Component Analysis to elucidate physical and chemical characteristics in the molecules that would be essential for the activity, employing VolSurf descriptors. The rate obtained explained 53% of the system total variance and revealed that a hydrophobic-hydrophilic balance in the molecules is required, since very polar or nonpolar substituents decrease the activity. Artificial Neural Networks (ANNs was also employed to determine key substituents by evaluating substitution patterns, using NMR data. This study had a high success rate (85% accuracy in the training set and 88% accuracy in the test set and showed polihydroxilations are essential for high activity and methoxylations and glicosilations primarily at positions C7, C3' and C4' decrease the activity.

  6. Stress tolerance of transgenic barley accumulating the alfalfa aldose reductase in the cytoplasm and the chloroplast.

    Science.gov (United States)

    Nagy, Bettina; Majer, Petra; Mihály, Róbert; Pauk, János; Horváth, Gábor V

    2016-09-01

    Barley represents one of the major crops grown worldwide; its genetic transformation provides an important tool for the improvement of crop quality and tolerance to environmental stress factors. Biotic and abiotic stresses produce reactive oxygen species in the plant cells that can directly oxidize the cellular components including lipid membranes; resulting in lipid peroxidation and subsequently the accumulation of reactive carbonyl compounds. In order to protect barley plants from the effects of stress-produced reactive carbonyls, an Agrobacterium-mediated transformation was carried out using the Medicago sativa aldose reductase (MsALR) gene. In certain transgenic lines the produced MsALR enzyme was targeted to the chloroplasts to evaluate its protective effect in these organelles. The dual fluorescent protein-based method was used for the evaluation of tolerance of young seedlings to diverse stresses; our results demonstrated that this technique could be reliably applied for the detection of cellular stress in a variety of conditions. The chlorophyll and carotenoid content measurements also supported the results of the fluorescent protein-based method and the stress-protective effect of the MsALR enzyme. Targeting of MsALR into the chloroplast has also resulted in increased stress tolerance, similarly to the observed effect of the cytosolic MsALR accumulation. The results of the DsRed/GFP fluorescent protein-based method indicated that both the cytosol and chloroplast accumulation of MsALR can increase the abiotic stress tolerance of transgenic barley lines. PMID:27469099

  7. Diallyl sulfide protects against N-nitrosodiethylamine-induced liver tumorigenesis: Role of aldose reductase

    Institute of Scientific and Technical Information of China (English)

    Safinaz S Ibrahim; Noha N Nassar

    2008-01-01

    AIM: To evaluate the protective effect of diallyl sulfide (DAS) against N-nitrosodiethylamine (NDEA)-induced liver carcinogenesis. METHODS: Male Wistar rats received either NDEA or NDEA together with DAS as protection. Liver energy metabolism was assessed in terms of lactate, pyruvate, lactate/pyruvate, ATP levels, lactate dehydrogenase (LDH) and glucose-6-phosphate dehydrogenase (G6PD) activities. In addition, membrane disintegration of the liver cells was evaluated by measuring lipid-peroxidation products, measured as malondialdehyde (MDA); nitric oxide (NO) levels; glucose-6-phosphatase (G6Pase), catalase (CAT) and superoxide dismutase (SOD) activities. Uver DNA level, glutathione-S-transferase (GST) and cytochrome c oxidase activities were used as DNA fragmentation indices. Aldose reductase (AR) activity was measured as an index for cancer cells resistant to chemotherapy and histopathological examination was performed on liver sections from different groups. RESULTS: NDEA significantly disturbed liver functions and most of the aforementioned indices. Treatment with DAS significantly restored liver functions and hepatocellular integrity; improved parameters of energy metabolism and suppressed free-radical generation. CONCLUSION: We provide evidence that DAS exerts a protective role on liver functions and tissue integrity in face of enhanced tumorigenesis caused by NDEA, as well as improving cancer-cell sensitivity to chemotherapy. This is mediated through combating oxidative stress of free radicals, improving the energy metabolic state of the cell, and enhancing the activity of G6Pase, GST and AR enzymes.

  8. Chemical modification of human muscle aldose reductase by pyridoxal 5'-phosphate

    International Nuclear Information System (INIS)

    Aldose reductase (ALR2) is a monomeric oxidoreductase (Mr, 37,000). This enzyme catalyzes the reduction of a wide variety of aliphatic and aromatic aldehydes to their corresponding alcohols. The ability to reduce D-glucose and utilize NADH distinguishes ALR2 from aldehyde reductase (ALR1) which is exclusively NADPH-dependent. As part of a study to determine active site residues critical for binding and catalysis they have investigated the behavior of ALR2 with pyridoxal phosphate (PLP). In contrast to ALR1, which is inactivated by PLP, the reaction of ALR2 with PLP results in a 2-3 fold activation with the incorporation of 1 mol of PLP/mol enzyme. However, despite a 3-fold increase in k/sub cat/, there is also a 13-14 fold increase in the Km for both coenzyme and substrate and catalytic efficiency (k/sub cat//Km) is actually decreased. Reaction of ALR2 with 3[H] PLP followed by digestion with endoproteinase Lys-C enabled the separation and purification by HPLC of a peptide containing a single pyridoxyllysine residue. The sequence of this 32 residue peptide is highly homologous with a peptide similarly obtained from pig and human ALR1 and is identical with one from pig ALR2. In all four enzymes, pig ALR1, ALR2; human ALR1, ALR2, a tetrapeptide containing the pyridoxylated lysine (I-P-K-S) shows absolute identity. Thus, despite differences in substrate and coenzyme specificity, the active site in both ALR1 and ALR2 is relatively conserved

  9. Synthesis and docking analysis of new heterocyclic system of tetrazolo[5',1':2,3][1,3,4]thiadiazepino [7,6-b]quinolines as aldose reductase inhibitors

    Directory of Open Access Journals (Sweden)

    Mohammad Saadatmandzadeh

    2014-09-01

    Conclusion: All of the best models formed strong hydrogen bonds with Trp 111 and Tyr 209 via tetrazole moiety. It was found that pi-pi interaction between Tyr 209, Trp 20 and His 110 side chain and quinolin moiety was one of the common factors in enzyme-inhibitor junction. It was found that both hydrogen bonding and hydrophobic interactions are important in the structure and function of biological molecules, especially for inhibition in a complex.

  10. Litsea japonica Extract Inhibits Aldose Reductase Activity and Hyperglycemia-Induced Lenticular Sorbitol Accumulation in db/db Mice

    Directory of Open Access Journals (Sweden)

    Junghyun Kim

    2015-01-01

    Full Text Available Aldose reductase (AR is the first and rate-limiting enzyme of the polyol pathway. AR-dependent synthesis of excess polyols leads to lens opacification in diabetic cataract. The purpose of this study is to investigate the protective effect of Litsea japonica extract (LJE on diabetes-induced lens opacification and its protective mechanism in db/db mice. Seven-week-old male db/db mice were treated with LJE (100 and 250 mg/kg body weight once a day orally for 12 weeks. LJE dose dependently inhibited rat lens aldose reductase activity in vitro (IC50 = 13.53 ± 0.74 µg/mL. In db/db mice, lens was slightly opacified, and lens fiber cells were swollen and ruptured. In addition, lenticular sorbitol accumulation was increased in db/db mice. However, the administration of LJE inhibited these lenticular sorbitol accumulation and lens architectural changes in db/db mice. Our results suggest that LJE might be beneficial for the treatment of diabetes-induced lens opacification. The ability of LJE to suppress lenticular sorbitol accumulation may be mediated by the inhibition of AR activity.

  11. Quantum mechanical calculation of electric fields and vibrational Stark shifts at active site of human aldose reductase.

    Science.gov (United States)

    Wang, Xianwei; Zhang, John Z H; He, Xiao

    2015-11-14

    Recent advance in biophysics has made it possible to directly measure site-specific electric field at internal sites of proteins using molecular probes with C = O or C≡N groups in the context of vibrational Stark effect. These measurements directly probe changes of electric field at specific protein sites due to, e.g., mutation and are very useful in protein design. Computational simulation of the Stark effect based on force fields such as AMBER and OPLS, while providing good insight, shows large errors in comparison to experimental measurement due to inherent difficulties associated with point charge based representation of force fields. In this study, quantum mechanical calculation of protein's internal electrostatic properties and vibrational Stark shifts was carried out by using electrostatically embedded generalized molecular fractionation with conjugate caps method. Quantum calculated change of mutation-induced electric field and vibrational Stark shift is reported at the internal probing site of enzyme human aldose reductase. The quantum result is in much better agreement with experimental data than those predicted by force fields, underscoring the deficiency of traditional point charge models describing intra-protein electrostatic properties. PMID:26567650

  12. Preparative isolation of aldose reductase inhibitory compounds from Nardostachys chinensis by elution-extrusion counter-current chromatography.

    Science.gov (United States)

    Paek, Ji Hun; Lim, Soon Sung

    2014-10-01

    A method combining enzyme assay-guided high-performance liquid chromatography (HPLC) micro-fractionation and elution-extrusion counter-current chromatography (EECCC) was developed to screen and separate aldose reductase (AR) inhibitory activities from those of the ethyl acetate (EtOAc) fraction of Nardostachys chinensis. Under the target-guidance of HPLC micro-fractionation, two phenolic compounds, three caffeoylquinic acid derivatives and two sesquiterpene were isolated by high-speed countercurrent chromatography (HSCCC) using elution modes of extrusion-elution. A one-step HSCCC isolation method was developed, which included a solvent system of n-hexane-EtOAc-methanol-water at a ratio of 2:8:3:7 (v/v/v/v). The chemical structures of the isolated compounds were determined using (1)H- and (13)C-nuclear magnetic resonance spectrometry. The compounds inhibiting AR in the EtOAc fraction of 70 % ethanol extracts of N. chinensis were identified as chlorogenic acid (2) and 1,5-di-O-caffeoylquinic acid (6). Our results indicate that the combined method of HPLC micro-fractionation and EECCC is fast, efficient, and reproducible for systematically isolating AR inhibitory compounds from complex natural products. PMID:24424606

  13. Quantum mechanical calculation of electric fields and vibrational Stark shifts at active site of human aldose reductase

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xianwei [Center for Optics and Optoelectronics Research, College of Science, Zhejiang University of Technology, Hangzhou, Zhejiang 310023 (China); State Key Laboratory of Precision Spectroscopy, Institute of Theoretical and Computational Science, East China Normal University, Shanghai 200062 (China); Zhang, John Z. H.; He, Xiao, E-mail: xiaohe@phy.ecnu.edu.cn [State Key Laboratory of Precision Spectroscopy, Institute of Theoretical and Computational Science, East China Normal University, Shanghai 200062 (China); NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai 200062 (China)

    2015-11-14

    Recent advance in biophysics has made it possible to directly measure site-specific electric field at internal sites of proteins using molecular probes with C = O or C≡N groups in the context of vibrational Stark effect. These measurements directly probe changes of electric field at specific protein sites due to, e.g., mutation and are very useful in protein design. Computational simulation of the Stark effect based on force fields such as AMBER and OPLS, while providing good insight, shows large errors in comparison to experimental measurement due to inherent difficulties associated with point charge based representation of force fields. In this study, quantum mechanical calculation of protein’s internal electrostatic properties and vibrational Stark shifts was carried out by using electrostatically embedded generalized molecular fractionation with conjugate caps method. Quantum calculated change of mutation-induced electric field and vibrational Stark shift is reported at the internal probing site of enzyme human aldose reductase. The quantum result is in much better agreement with experimental data than those predicted by force fields, underscoring the deficiency of traditional point charge models describing intra-protein electrostatic properties.

  14. Quantum mechanical calculation of electric fields and vibrational Stark shifts at active site of human aldose reductase

    International Nuclear Information System (INIS)

    Recent advance in biophysics has made it possible to directly measure site-specific electric field at internal sites of proteins using molecular probes with C = O or C≡N groups in the context of vibrational Stark effect. These measurements directly probe changes of electric field at specific protein sites due to, e.g., mutation and are very useful in protein design. Computational simulation of the Stark effect based on force fields such as AMBER and OPLS, while providing good insight, shows large errors in comparison to experimental measurement due to inherent difficulties associated with point charge based representation of force fields. In this study, quantum mechanical calculation of protein’s internal electrostatic properties and vibrational Stark shifts was carried out by using electrostatically embedded generalized molecular fractionation with conjugate caps method. Quantum calculated change of mutation-induced electric field and vibrational Stark shift is reported at the internal probing site of enzyme human aldose reductase. The quantum result is in much better agreement with experimental data than those predicted by force fields, underscoring the deficiency of traditional point charge models describing intra-protein electrostatic properties

  15. Berberine ameliorates renal injury in streptozotocin-induced diabetic rats by suppression of both oxidative stress and aldose reductase

    Institute of Scientific and Technical Information of China (English)

    LIU Wei-hua; HUANG Wen-ge; CHEN Feng-ying; LIU Pei-qing; HEI Zi-qing; NIE Hong; TANG Fu-tian; HUANG He-qing; LI Xue-juan; DENG Yan-hui; CHEN Shao-rui; GUO Fen-fen

    2008-01-01

    Background Berberine is one of the main constituents of Coptidis rhizoma (CR) and Cortex phellodendri, In this study, we investigated the beneficial effects of berberine on renal function and its possible mechanisms in rats with diabetic nephropathy(DN). Methods Male Wistar rats were divided into three groups: normal, diabetic model, and berberine treatment groups. Rats in the diabetic model and berberine treatment groups were induced to diabetes by intraperitonal injection with streptozotocin(STZ). Glomerular area, glomerular volume, fasting blood glucose(FBG), blood urea nitrogen(BUN), serum creatinine (Cr)and urine protein for 24 hours(UP24h) were measured using commercially available kits. Meanwhile, the activity of superoxide dismutase (SOD), content of malondialdehyde (MDA) in serum, activity of aldose reductase (AR)and the expression of AR mRNA and protein in kidney were detected by different methods. Results The result showed that oral administration of berberine (200mg·kg-1·d-1) significantly ameliorated the ratio of kidney weight to body weight. Glomerular area, glomerular volume, FBG, BUN, Cr and UP24h were significantly decreased in the berberine treatment group compared with the diabetic model group(P<0.05). Berberine treatment significantly increased serum SOD activity and decreased the content of MDA compared with diabetic model group(P<0.05). AR activity as well as the expression of AR mRNA and protein in the kidney was markedly decreased in the berberine treatment group compared with diabetic model group (P<0.05). Conclusion These results suggested that berberine could ameliorate renal dysfunction in DN rats through controlling blood glucose, reduction of oxidative stress and inhibition of the activation of the polyol pathway.

  16. SIRT1 contributes to aldose reductase expression through modulating NFAT5 under osmotic stress: In vitro and in silico insights.

    Science.gov (United States)

    Timucin, Ahmet Can; Bodur, Cagri; Basaga, Huveyda

    2015-11-01

    So far, a myriad of molecules were characterized to modulate NFAT5 and its downstream targets. Among these NFAT5 modifiers, SIRT1 was proposed to have a promising role in NFAT5 dependent events, yet the exact underlying mechanism still remains obscure. Hence, the link between SIRT1 and NFAT5-aldose reductase (AR) axis under osmotic stress, was aimed to be delineated in this study. A unique osmotic stress model was generated and its mechanistic components were deciphered in U937 monocytes. In this model, AR expression and nuclear NFAT5 stabilization were revealed to be positively regulated by SIRT1 through utilization of pharmacological modulators. Overexpression and co-transfection studies of NFAT5 and SIRT1 further validated the contribution of SIRT1 to AR and NFAT5. The involvement of SIRT1 activity in these events was mediated via modification of DNA binding of NFAT5 to AR ORE region. Besides, NFAT5 and SIRT1 were also shown to co-immunoprecipitate under isosmotic conditions and this interaction was disrupted by osmotic stress. Further in silico experiments were conducted to investigate if SIRT1 directly targets NFAT5. In this regard, certain lysine residues of NFAT5, when kept deacetylated, were found to contribute to its DNA binding and SIRT1 was shown to directly bind K282 of NFAT5. Based on these in vitro and in silico findings, SIRT1 was identified, for the first time, as a novel positive regulator of NFAT5 dependent AR expression under osmotic stress in U937 monocytes. PMID:26297866

  17. Deficiency of aldose reductase attenuates inner retinal neuronal changes in a mouse model of retinopathy of prematurity.

    Science.gov (United States)

    Fu, Zhongjie; Nian, Shen; Li, Suk-Yee; Wong, David; Chung, Sookja K; Lo, Amy C Y

    2015-09-01

    Retinopathy of prematurity (ROP) is a leading cause of childhood blindness where vascular abnormality and retinal dysfunction are reported. We showed earlier that genetic deletion of aldose reductase (AR), the rate-limiting enzyme in the polyol pathway, reduced the neovascularization through attenuating oxidative stress induction in the mouse oxygen-induced retinopathy (OIR) modeling ROP. In this study, we further investigated the effects of AR deficiency on retinal neurons in the mouse OIR. Seven-day-old wild-type and AR-deficient mice were exposed to 75 % oxygen for 5 days and then returned to room air. Electroretinography was used to assess the neuronal function at postnatal day (P) 30. On P17 and P30, retinal cytoarchitecture was examined by morphometric analysis and immunohistochemistry for calbindin, protein kinase C alpha, calretinin, Tuj1, and glial fibrillary acidic protein. In OIR, attenuated amplitudes and delayed implicit time of a-wave, b-wave, and oscillatory potentials were observed in wild-type mice, but they were not significantly changed in AR-deficient mice. The morphological changes of horizontal, rod bipolar, and amacrine cells were shown in wild-type mice and these changes were partly preserved with AR deficiency. AR deficiency attenuated the Müller cell gliosis induced in OIR. Our observations demonstrated AR deficiency preserved retinal functions in OIR and AR deficiency could partly reduce the extent of retinal neuronal histopathology. These findings suggested a therapeutic potential of AR inhibition in ROP treatment with beneficial effects on the retinal neurons. PMID:25921391

  18. Identification and Quantification of Aldose Reductase Inhibitory Flavonoids in Herbal Formulation and Extract of Gymnema sylvestre Using HPLC-PDA and LC-MS/MS

    Directory of Open Access Journals (Sweden)

    Nanjappan Satheeshkumar

    2014-01-01

    Full Text Available Adulteration of herbal supplements is a major issue for many countries. A simple and reliable HPLC-PDA method was developed for quantification of aldose reductase inhibitory flavonoids rutin, quercetin, and kaempferol. The chromatographic separation was performed on a Fortis C18 column in gradient mode with detection at 267 nm. The presence of these markers was confirmed through the accurate m/z values and MS/MS data obtained using quadruple time of flight mass spectrometry (QTOF-MS. The proposed method was successfully applied to examine the amount of these active constituents in antiobese polyherbal formulation and plant extract of Gymnema sylvestre.

  19. SCREENING OF HMG CO A REDUCTASE INHIBITOR PRODUCING MARINE ACTINOMYCETES

    OpenAIRE

    SRINU, PHANI BHUSHAN,MOGES, SRILAKSHMI, SANKAR, PRABHAKAR,LAKSHMINARAYANA

    2013-01-01

    The objective of the present study was screening of 3-hydroxy-3- methyl glutaryl Co A (HMG CoA) reductase inhibitor producing marine actinomycetes. A total of 65 morphologically different actinomycetes were screened for HMG CoA reductase inhibitor production in a two stage submerged fermentation and evaluated for HMG CoA reductase inhibitor activity by agar diffusion and thin layer chromatography technique using lovostatin as a control. Among 65 marine Actinomycete strains, only one strain pr...

  20. An overview on 5alpha-reductase inhibitors.

    Science.gov (United States)

    Aggarwal, Saurabh; Thareja, Suresh; Verma, Abhilasha; Bhardwaj, Tilak Raj; Kumar, Manoj

    2010-02-01

    Benign prostatic hyperplasia (BPH) is the noncancerous proliferation of the prostate gland associated with benign prostatic obstruction and lower urinary tract symptoms (LUTS) such as frequency, hesitancy, urgency, etc. Its prevalence increases with age affecting around 70% by the age of 70 years. High activity of 5alpha-reductase enzyme in humans results in excessive dihydrotestosterone levels in peripheral tissues and hence suppression of androgen action by 5alpha-reductase inhibitors is a logical treatment for BPH as they inhibit the conversion of testosterone to dihydrotestosterone. Finasteride (13) was the first steroidal 5alpha-reductase inhibitor approved by U.S. Food and Drug Administration (USFDA). In human it decreases the prostatic DHT level by 70-90% and reduces the prostatic size. Dutasteride (27) another related analogue has been approved in 2002. Unlike Finasteride, Dutasteride is a competitive inhibitor of both 5alpha-reductase type I and type II isozymes, reduced DHT levels >90% following 1 year of oral administration. A number of classes of non-steroidal inhibitors of 5alpha-reductase have also been synthesized generally by removing one or more rings from the azasteroidal structure or by an early non-steroidal lead (ONO-3805) (261). In this review all categories of inhibitors of 5alpha-reductase have been covered. PMID:19879888

  1. Inhibition of Aldose Activity by Essential Phytochemicals of Cymbopogon citratus (DC.) Stapf

    OpenAIRE

    P .Vyshali; K.J.Thara Saraswati; Rajeshwari Sanakal; B.B.Kaliwal

    2011-01-01

    The ambiguity of whether aldose reductase, an enzyme of polyol pathway, is linked to diabetesand its complication has been receded based on the recent studies made on the inhibition of its(Aldose reductase) activity. In our current study, we have used an in silico approach (moleculardocking) to analyze the effect of essential phytochemicals obtained from Cymbopogon citratus onthe aldose reductase activity. C.citratus is grown extensively in tropical countries including Indiafor perfumery and ...

  2. 人醛糖还原酶基因在酿酒酵母中的诱导表达及活性分析%Induced expression and activity analysis of human aldose reductase gene in Saccharomyces cerevisiae

    Institute of Scientific and Technical Information of China (English)

    翟冰; 叶玲; 刘静; 刘建伟

    2011-01-01

    Objective To construct the Saccharvmyces cerevisiae cell strains expressing aldose reductase(AR) and AR-green fluorescent protein(AR-GFP) fusion protein, and to detect the target gene expression and the AR enzyme activity. Methods The yeast expression plasmids pYEX-BX inserted with AR and AR::GFP fusion gene were transformed into the yeast strain ENVScl, which were named as XAR and XAG strains respectively. The blank pYEX-BX strain was used as the normal control. The growth curves and the fluorescence were determined in all strains. Northern blot, Western blot and the fluorescent method were used to detect the AR mRNA transcription, AR protein expression, and the AR activity respectively. Results There was no significant difference in the growth rates among three strains. There was a linear relationship between relative fluorescence of the XAG and the growth time. The mRNA transcription and protein expression of AR and AR::GFP were sustainable and stable in XAR and XAG strains. The AR activities in the two strains were both proved by the fluorescent method. Conclusion The yeast expression strain of AR was constructed successfully, which lays basis for its application in the researches on pathogenic mechanism of AR and preliminary screening of new AR inhibitors.%目的 建立人醛糖还原酶(AR)及其与绿色荧光蛋白(GFP)融合表达的酿酒酵母细胞表达株,检测细胞中目的基因的表达及蛋白活性.方法 将含目的基因AR及融合基因AR::GFP的重组质粒pYEX-BX转化酵母细胞INVScl,得到宿主菌株XAR,XAG及对照菌株YEX.观察酵母细胞生长曲线及GFP荧光信号;Northern blot检测细胞中AR mRNA转录;Western blot检测AR蛋白表达;荧光法测定AR活性.结果 三菌株生长速率无明显差异;XAG菌株相对荧光强度与生长时间成线性关系;XAR,XAG菌株分别有持续、稳定的目的基因mRNA转录及目的蛋白表达,并具有AR活性.结论 成功构建了AR基因的酵母表达株,为

  3. The use of 5-alpha reductase inhibitors for the prevention of prostate cancer.

    Science.gov (United States)

    Yu, Eun-mi; El-Ayass, Walid; Aragon-Ching, Jeanny B

    2010-07-01

    The use of 5-alpha-reductase inhibitors has been studied not only in benign prostatic hyperplasia, but as a chemopreventive strategy in prostate cancer. Both finasteride and dutasteride, 5 alpha-reductase inhibitors (5ARI), have been shown to decrease the risk of prostate cancer. The results of the REDUCE trial using the dual alpha-reductase isoenzyme inhibitor dutasteride, has recently been published by Andriole et al. in the New England Journal of Medicine. Certain considerations regarding its use and applicability to men with high risk of developing prostate cancer are herein discussed. PMID:20574153

  4. 5α-reductase inhibitors, antiviral and anti-tumor activities of some steroidal cyanopyridinone derivatives.

    Science.gov (United States)

    Al-Mohizea, Abdullah M; Al-Omar, Mohamed A; Abdalla, Mohamed M; Amr, Abdel-Galil E

    2012-01-01

    We herein report the 5α-reductase inhibitors, antiviral and anti-tumor activities of some synthesized heterocyclic cyanopyridone and cyanothiopyridone derivatives fused with steroidal structure. Initially the acute toxicity of the compounds was assayed via the determination of their LD(50). All the compounds, except 3b, were interestingly less toxic than the reference drug (Prednisolone(®)). Seventeen heterocyclic derivatives containing a cyanopyridone or cyanothiopyridone rings fused to a steroidal moiety were synthesized and screened for their 5α-reductase inhibitors, antiviral and anti-tumor activities comparable to that of Anastrozole, Bicalutamide, Efavirenz, Capravirine, Ribavirin, Oseltamivir and Amantadine as the reference drugs. Some of the compounds exhibited better 5α-reductase inhibitors, antiviral and anti-tumor activities than the reference drugs. The detailed 5α-reductase inhibitors, antiviral and anti-tumor activities of the synthesized compounds were reported. PMID:22057085

  5. Design and synthesis of hepatoselective, pyrrole-based HMG-CoA reductase inhibitors.

    Science.gov (United States)

    Pfefferkorn, Jeffrey A; Song, Yuntao; Sun, Kuai-Lin; Miller, Steven R; Trivedi, Bharat K; Choi, Chulho; Sorenson, Roderick J; Bratton, Larry D; Unangst, Paul C; Larsen, Scott D; Poel, Toni-Jo; Cheng, Xue-Min; Lee, Chitase; Erasga, Noe; Auerbach, Bruce; Askew, Valerie; Dillon, Lisa; Hanselman, Jeffrey C; Lin, Zhiwu; Lu, Gina; Robertson, Andrew; Olsen, Karl; Mertz, Thomas; Sekerke, Catherine; Pavlovsky, Alexander; Harris, Melissa S; Bainbridge, Graeme; Caspers, Nicole; Chen, Huifen; Eberstadt, Matthias

    2007-08-15

    This manuscript describes the design and synthesis of a series of pyrrole-based inhibitors of HMG-CoA reductase for the treatment of hypercholesterolemia. Analogs were optimized using structure-based design and physical property considerations resulting in the identification of 44, a hepatoselective HMG-CoA reductase inhibitor with excellent acute and chronic efficacy in a pre-clinical animal models. PMID:17574412

  6. Inhibition of Aldose Activity by Essential Phytochemicals of Cymbopogon citratus (DC. Stapf

    Directory of Open Access Journals (Sweden)

    P .Vyshali

    2011-12-01

    Full Text Available The ambiguity of whether aldose reductase, an enzyme of polyol pathway, is linked to diabetesand its complication has been receded based on the recent studies made on the inhibition of its(Aldose reductase activity. In our current study, we have used an in silico approach (moleculardocking to analyze the effect of essential phytochemicals obtained from Cymbopogon citratus onthe aldose reductase activity. C.citratus is grown extensively in tropical countries including Indiafor perfumery and pharmaceuticals. The essential phytochemicals of C.citratus like Myrcene,Citral, and Geraniol have been used as ligand for the molecular docking analysis with Aldosereductase as receptor. The docking analysis showed Myrcene, with binding energy of -8.76Kcal/mol is best amongst Citral and Geraniol which are having binding energies of -7.24 Kcal/moland -7.93 Kcal/mol respectively for inhibiting the activity of Aldose reductase.

  7. Chelation: A Fundamental Mechanism of Action of AGE Inhibitors, AGE Breakers, and Other Inhibitors of Diabetes Complications

    OpenAIRE

    Nagai, Ryoji; Murray, David B.; Metz, Thomas O.; Baynes, John W.

    2012-01-01

    This article outlines evidence that advanced glycation end product (AGE) inhibitors and breakers act primarily as chelators, inhibiting metal-catalyzed oxidation reactions that catalyze AGE formation. We then present evidence that chelation is the most likely mechanism by which ACE inhibitors, angiotensin receptor blockers, and aldose reductase inhibitors inhibit AGE formation in diabetes. Finally, we note several recent studies demonstrating therapeutic benefits of chelators for diabetic car...

  8. Current status of 5α-reductase inhibitors in the treatment of benign hyperplasia of prostate

    Directory of Open Access Journals (Sweden)

    Kumar Vijay

    2008-04-01

    Full Text Available Benign prostatic hyperplasia (BPH is a common problem in aging men, which is associated with lower urinary tract symptoms. This condition is dependent on the presence of androgens for its progression, and medical therapy is the first-line treatment for BPH patients with moderate-to-severe symptoms and includes the use of either alpha 1-adrenergic blockers or 5α-reductase inhibitors. Adrenergic blocking drugs reduce the dynamic component while the 5α-reductase inhibitors reduce the static component of bladder outlet obstruction in BPH. By inhibiting the generation of active form of testosterone, viz., dihydrotestosterone, the 5α-reductase inhibitors not only reduce the symptoms of BPH but also decrease the need for surgery and further progression of BPH. Besides, prolonged use of combination of 5α-reductase inhibitors and alpha 1-adrenergic blockers has been found to be more beneficial than either of the two drugs given alone. This review gives a brief account of rationale and efficacy of treatment by 5α-reductase inhibitors in the management of BPH.

  9. Steroidal pyrazolines evaluated as aromatase and quinone reductase-2 inhibitors for chemoprevention of cancer.

    Science.gov (United States)

    Abdalla, Mohamed M; Al-Omar, Mohamed A; Bhat, Mashooq A; Amr, Abdel-Galil E; Al-Mohizea, Abdullah M

    2012-05-01

    The aromatase and quinone reductase-2 inhibition of synthesized heterocyclic pyrazole derivatives fused with steroidal structure for chemoprevention of cancer is reported herein. All compounds were interestingly less toxic than the reference drug (Cyproterone(®)). The aromatase inhibitory activities of these compounds were much more potent than the lead compound resveratrol, which has an IC(50) of 80 μM. In addition, all the compounds displayed potent quinone reductase-2 inhibition. Initially the acute toxicity of the compounds was assayed via the determination of their LD(50). The aromatase and quinone reductase-2 inhibitors resulting from this study have potential value in the treatment and prevention of cancer. PMID:22361454

  10. Alpha 1-blockers vs 5 alpha-reductase inhibitors in benign prostatic hyperplasia. A comparative review

    DEFF Research Database (Denmark)

    Andersen, J T

    1995-01-01

    During recent years, pharmacological treatment of symptomatic benign prostatic hyperplasia (BPH) has become the primary treatment choice for an increasing number of patients. The 2 principal drug classes employed are alpha 1-blockers and 5 alpha-reductase inhibitors. Current information from...... patients who will respond well to alpha 1-blockers have yet to be identified, and data concerning the long term effects of these drugs are not yet available. 5 alpha-Reductase inhibitors have a slow onset of effect, but treatment leads to improvement in symptoms, reduction of the size of the prostate gland...... and improvement in objective parameters for bladder outflow obstruction. Approximately 30 to 50% of patients will respond to treatment with 5 alpha-reductase inhibitors. The definitive role of pharmacological treatment in symptomatic BPH remains to be established, although it seems that patients unfit...

  11. Steroid 5 α-reductase inhibitors targeting BPH and prostate cancer.

    Science.gov (United States)

    Schmidt, Lucy J; Tindall, Donald J

    2011-05-01

    Steroid 5 alpha-reductase inhibitors (5ARIs) have been approved for use clinically in treatment of benign prostate hyperplasia (BPH) and accompanying lower urinary tract symptoms (LUTS) and have also been evaluated in clinical trials for prevention and treatment of prostate cancer. There are currently two steroidal inhibitors in use, finasteride and dutasteride, both with distinct pharmacokinetic properties. This review will examine the evidence presented by various studies supporting the use of these steroidal inhibitors in the prevention and treatment of prostate disease. Article from the Special issue on Targeted Inhibitors. PMID:20883781

  12. Design and synthesis of novel, conformationally restricted HMG-CoA reductase inhibitors.

    Science.gov (United States)

    Pfefferkorn, Jeffrey A; Choi, Chulho; Song, Yuntao; Trivedi, Bharat K; Larsen, Scott D; Askew, Valerie; Dillon, Lisa; Hanselman, Jeffrey C; Lin, Zhiwu; Lu, Gina; Robertson, Andrew; Sekerke, Catherine; Auerbach, Bruce; Pavlovsky, Alexander; Harris, Melissa S; Bainbridge, Graeme; Caspers, Nicole

    2007-08-15

    Using structure-based design, a novel series of conformationally restricted, pyrrole-based inhibitors of HMG-CoA reductase were discovered. Leading analogs demonstrated potent inhibition of cholesterol synthesis in both in vitro and in vivo models and may be useful for the treatment of hypercholesterolemia and related lipid disorders. PMID:17574411

  13. Dual-color immunofluorescent labeling with quantum dots of the diabetes-associated proteins aldose reductase and Toll-like receptor 4 in the kidneys of diabetic rats

    Directory of Open Access Journals (Sweden)

    Liu XM

    2015-05-01

    Full Text Available Xiaomin Liu,1,* Rui Hu,2,* Hongwei Lian,1,3 Yang Liu,4 Jing Liu,1 Jianwei Liu,1 Guimiao Lin,5 Liwei Liu,6 Xiaojian Duan,1 Ken-Tye Yong,2 Ling Ye1 1Institute of Gerontology and Geriatrics, Chinese PLA General Hospital, Beijing Key Lab of Aging and Geriatrics, Beijing, People’s Republic of China; 2School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, Singapore; 3Department of Emergency Medicine, Peking University Third Hospital, Beijing, 4Department of Geriatric Nephrology, Chinese PLA General Hospital, Beijing, 5Key Lab of Biomedical Engineering, School of Medical Sciences, Shenzhen University, Shenzhen, 6School of Science, Changchun University of Science and Technology, Changchun, People’s Republic of China *These authors contributed equally to this work Abstract: Diabetes is one of the major chronic diseases diagnosed worldwide with a common complication of diabetic nephropathy (DN. There are multiple possible mechanisms associated with DN. Aldose reductase (AR and Toll-like receptor 4 (TLR4 may be involved in the occurrence and development of DN. Here, we describe the distribution of AR and TLR4 in cells and renal tissues of diabetic rats through a quantum dot (QD-based immunofluorescence technique and conventional immunohistochemistry. As a new type of nanosized fluorophore, QDs have been recognized in imaging applications and have broad prospects in biomedical research. The results of the reported study demonstrate that both the AR and the TLR4 proteins were upregulated in the renal tissues of diabetic rats. Further, to explore the relationship between AR and TLR4 in the pathogenesis of DN, a dual-color immunofluorescent labeling technique based on QDs was applied, where the expressions of AR and TLR4 in the renal tissues of diabetic rats were simultaneously observed – for the first time, as far as we are aware. The optimized QD-based immunofluorescence technique has not only shown a satisfying

  14. Synthetic and Crystallographic Studies of a New Inhibitor Series Targeting Bacillus anthracis Dihydrofolate Reductase

    Energy Technology Data Exchange (ETDEWEB)

    Beierlein, J.; Frey, K; Bolstad, D; Pelphrey, P; Joska, T; Smith, A; Priestley, N; Wright, D; Anderson, A

    2008-01-01

    Bacillus anthracis, the causative agent of anthrax, poses a significant biodefense danger. Serious limitations in approved therapeutics and the generation of resistance have produced a compelling need for new therapeutic agents against this organism. Bacillus anthracis is known to be insensitive to the clinically used antifolate, trimethoprim, because of a lack of potency against the dihydrofolate reductase enzyme. Herein, we describe a novel lead series of B. anthracis dihydrofolate reductase inhibitors characterized by an extended trimethoprim-like scaffold. The best lead compound adds only 22 Da to the molecular weight and is 82-fold more potent than trimethoprim. An X-ray crystal structure of this lead compound bound to B. anthracis dihydrofolate reductase in the presence of NADPH was determined to 2.25 A resolution. The structure reveals several features that can be exploited for further development of this lead series.

  15. Multiple aldehyde reductases of human brain.

    Science.gov (United States)

    Hoffman, P L; Wermuth, B; von Wartburg, J P

    1980-01-01

    Human brain contains four forms of aldehyde reducing enzymes. One major activity, designated AR3, has properties indicating its identity with the NADPH-dependent aldehyde reductase, EC 1.1.1.2. The other major form of human brain enzyme, AR1, which is also NADPH-dependent, reduces both aldehyde and ketone-containing substrates, including vitamin K3 (menadione) and daunorubicin, a cancer chemotherapeutic agent. This enzyme is very sensitive to inhibition by the flavonoids quercitrin and quercetine, and may be analogous to a daunorubicin reductase previously described in liver of other species. One minor form of human brain aldehyde reductase, AR2, demonstrates substrate specificity and inhibitor sensitivity which suggest its similarity to aldose reductases found in lens and other tissues of many species. This enzyme, which can also use NADH as cofactor to some extent, is the most active in reducing the aldehyde derivatives of the biogenic amines. The fourth human brain enzyme ("SSA reductase") differs from the other forms in its ability to use NADH as well as or better than NADPH as cofactor, and in its molecular weight, which is nearly twice that of the other forms. It is quite specific for succinic semialdehyde (SSA) as substrate, and was found to be significantly inhibited only by quercetine and quercitrin. AR3 can also reduce SSA, and both enzymes may contribute to the production of gamma-hydroxybutyric acid in vivo. These results indicate that the human brain aldehyde reductases can play relatively specific physiologic roles. PMID:7424738

  16. Positive pleiotropic effects of HMG-CoA reductase inhibitor on vitiligo

    Directory of Open Access Journals (Sweden)

    Jobin Jean

    2004-05-01

    Full Text Available Abstract Background HMG-CoA reductase inhibitors (statins are commonly used in medicine to control blood lipid disorder. Large clinical trials have demonstrated that statins greatly reduces cardiovascular-related morbidity and mortality in patients with and without coronary artery disease. Also, the use of HMG-CoA reductase inhibitors has been reported to have immunosuppressive effects. Case presentation We describe an unusual case of regression of vitiligo in a patient treated with high dose simvastatin. The relation between simvastatin and regression of vitiligo in this case report may be related to the autoimmune pathophysiology of the disease. Conclusion This unexpected beneficial impact provides another scientific credence to the hypothesis that immune mechanisms play a role in the development of vitiligo and that the use of statins as immuno-modulator could be of use not only for treatment relative to organ transplant but in other pathologies such as vitiligo.

  17. Discovery of pyrrole-based hepatoselective ligands as potent inhibitors of HMG-CoA reductase.

    Science.gov (United States)

    Bratton, Larry D; Auerbach, Bruce; Choi, Chulho; Dillon, Lisa; Hanselman, Jeffrey C; Larsen, Scott D; Lu, Gina; Olsen, Karl; Pfefferkorn, Jeffrey A; Robertson, Andrew; Sekerke, Catherine; Trivedi, Bharat K; Unangst, Paul C

    2007-08-15

    In an effort to identify hepatoselective inhibitors of HMG-CoA reductase, two series of pyrroles were synthesized and evaluated. Efforts were made to modify (3R,5R)-7-[3-(4-fluorophenyl)-1-isopropyl-4-phenyl-5-phenylcarbamoyl-1H-pyrrol-2-yl]-3,5-dihydroxy-heptanoic acid sodium salt 30 in order to reduce its lipophilicity and therefore increase hepatoselectivity. Two strategies that were explored were replacement of the lipophilic 3-phenyl substituent with either a polar function (pyridyl series) or with lower alkyl substituents (lower alkyl series) and attachment of additional polar moieties at the 2-position of the pyrrole ring. One compound was identified to be both highly hepatoselective and active in vivo. We report the discovery, synthesis, and optimization of substituted pyrrole-based hepatoselective ligands as potent inhibitors of HMG-CoA reductase for reducing low density lipoprotein cholesterol (LDL-c) in the treatment of hypercholesterolemia. PMID:17560788

  18. 5alpha-Reductase inhibitor treatment of prostatic diseases: background and practical implications.

    Science.gov (United States)

    Dörsam, J; Altwein, J

    2009-01-01

    This literature review discusses the theoretical background of 5alpha-reductase inhibitor (5ARI) treatment and the resulting clinical implications. A Medline-based search for peer-reviewed articles addressing 5ARIs, benign prostatic hyperplasia and prostate cancer was performed. The 5ARIs Finasteride and Dutasteride, which specifically inhibit the production of dihydrotestosterone by acting as competitive inhibitors of 5alpha-reductase, are clinically well tolerated and represent an effective treatment option for benign prostatic obstruction. Finasteride is the first compound which has a proven efficacy in chemoprevention of prostate cancer. The aim of this review was to elucidate, if there are sufficient data available to point out clinically relevant differences between the drugs. Both compounds achieve a significant reduction of prostate volume, an improvement of symptoms and a lower risk of acute urinary retention. Whether the different pharmacokinetic and pharmacodynamic properties of Finasteride and Dutasteride are of clinical importance cannot be judged at this time. PMID:19030020

  19. Battling Prostate Cancer with 5-Alpha-Reductase Inhibitors: a Pyrrhic Victory?

    OpenAIRE

    Hoffman, Richard M.; Richard G. Roberts; Barry, Michael J.

    2011-01-01

    Given the relatively small impact of prostate cancer screening on cancer mortality, experts are now suggesting that chemoprevention with 5-alpha-reductase inhibitors (5-ARI) may be a more effective strategy for cancer control. Two large placebo-controlled randomized trials found that men receiving 5-ARI were about 25% less likely than controls to be detected with cancer. However, most cancers were detected on routine biopsies required by study protocols. The benefit from receiving 5-ARI was m...

  20. Clinical Effects of Discontinuing 5-Alpha Reductase Inhibitor in Patients With Benign Prostatic Hyperplasia

    OpenAIRE

    Kim, Won; Jung, Jae Hung; Kang, Tae Wook; Song, Jae Mann; Chung, Hyun Chul

    2014-01-01

    Purpose To assess changes in lower urinary tract symptoms (LUTS), prostate volume, and serum prostate-specific antigen (PSA) after discontinuation of 5-alpha reductase inhibitor (5ARI) combination therapy in patients with benign prostatic hyperplasia (BPH). Materials and Methods From December 2003 to December 2012, data were collected retrospectively from 81 men more than 40 years of age with moderate to severe BPH symptoms (International Prostate Symptom Score [IPSS]≥8). The men were classif...

  1. 5-α reductase inhibitors and prostate cancer prevention: where do we turn now?

    OpenAIRE

    Hamilton Robert J; Freedland Stephen J

    2011-01-01

    Abstract With the lifetime risk of being diagnosed with prostate cancer so great, an effective chemopreventive agent could have a profound impact on the lives of men. Despite decades of searching for such an agent, physicians still do not have an approved drug to offer their patients. In this article, we outline current strategies for preventing prostate cancer in general, with a focus on the 5-α-reductase inhibitors (5-ARIs) finasteride and dutasteride. We discuss the two landmark randomized...

  2. Identification and Characterization of Inhibitors of Bacterial Enoyl-Acyl Carrier Protein Reductase

    OpenAIRE

    Ling, Losee L.; Xian, Jun; Ali, Syed; Geng, Bolin; Fan, Jun; Mills, Debra M.; Arvanites, Anthony C.; Orgueira, Hernan; Ashwell, Mark A.; Carmel, Gilles; Xiang, Yibin; Moir, Donald T.

    2004-01-01

    Bacterial enoyl-acyl carrier protein reductase (ENR) catalyzes an essential step in fatty acid biosynthesis. ENR is an attractive target for narrow-spectrum antibacterial drug discovery because of its essential role in metabolism and its sequence conservation across many bacterial species. In addition, the bacterial ENR sequence and structural organization are distinctly different from those of mammalian fatty acid biosynthesis enzymes. High-throughput screening to identify inhibitors of Esch...

  3. Role of 5 alpha-reductase inhibitors in the management of prostate cancer

    OpenAIRE

    Hudak, Steven J.; Hernandez, Javier; Thompson, Ian M

    2006-01-01

    Prostate cancer is one of the most complex and enigmatic oncologic problems in medicine. It is highly prevalent, particularly in elderly males. Unfortunately, its generally protracted and variable clinical course and high association with treatment-related morbidity raise serious questions about the ideal treatment strategy for the individual patient. 5 alpha-reductase (5AR) inhibitors have a dramatic effect on benign prostatic disease with low toxicity. Thus, there is much interest in the po...

  4. Current Status of 5α-Reductase Inhibitors in Prostate Disease Management

    OpenAIRE

    Kang, Dong Il; Chung, Jae Il

    2013-01-01

    The key enzyme in the androgen synthesis and androgen receptor pathways is 5α-reductase (5-AR), which occurs as three isoenzymes. Types I and II 5-ARs the most important clinically, and two different 5-AR inhibitors (5-ARIs), finasteride and dutasteride, have been developed. Several urology associations have recommended and upgraded the use of 5-ARIs for an enlarged prostate with lower urinary tract symptoms. In the Prostate Cancer Prevention Trial and the Reduction by Dutasteride of Prostate...

  5. Biochemical and antitumor activity of trimidox, a new inhibitor of ribonucleotide reductase.

    Science.gov (United States)

    Szekeres, T; Gharehbaghi, K; Fritzer, M; Woody, M; Srivastava, A; van't Riet, B; Jayaram, H N; Elford, H L

    1994-01-01

    Trimidox (3,4,5-trihydroxybenzamidoxime), a newly synthesized analog of didox (N,3,4-trihydroxybenzamide) reduced the activity of ribonucleotide reductase (EC 1.17.4.1) in extracts of L1210 cells by 50% (50% growth-inhibitory concentration, IC50) at 5 microM, whereas hydroxyurea, the only ribonucleotide reductase inhibitor in clinical use, exhibited an IC50 of 500 microM. Ribonucleotide reductase activity was also measured in situ by incubating L1210 cells for 24 h with trimidox at 7.5 microM, a concentration that inhibits cell proliferation by 50% (IC50) or at 100 microM for 2 h; these concentrations resulted in a decrease in enzyme activity to 22% and 50% of the control value, respectively. Trimidox and hydroxyurea were cytotoxic to L1210 cells with IC50 values of 7.5 and 50 microM, respectively. Versus ribonucleotide reductase, trimidox and hydroxyurea yielded IC50 values of 12 and 87 microM, respectively. A dose-dependent increase in life span was observed in mice bearing intraperitoneally transplanted L1210 tumors. Trimidox treatment (200 mg/kg; q1dx9) significantly increased the life span of mice bearing L1210 leukemia (by 82% in male mice and 112% in female mice). The anti-tumor activity appeared more pronounced in female mice than in male mice. Viewed in concert, these findings suggest that trimidox is a new and potent inhibitor of ribonucleotide reductase and that it is a promising candidate for the chemotherapy of cancer in humans. PMID:8174204

  6. Synthesis and characterization of potent inhibitors of Trypanosoma cruzi dihydrofolate reductase

    Energy Technology Data Exchange (ETDEWEB)

    Schormann, Norbert; Velu, Sadanandan E.; Murugesan, Srinivasan; Senkovich, Olga; Walker, Kiera; Chenna, Bala C.; Shinkre, Bidhan; Desai, Amar; Chattopadhyay, Debasish (UAB)

    2010-09-17

    Dihydrofolate reductase (DHFR) of the parasite Trypanosoma cruzi (T. cruzi) is a potential target for developing drugs to treat Chagas disease. We have undertaken a detailed structure-activity study of this enzyme. We report here synthesis and characterization of six potent inhibitors of the parasitic enzyme. Inhibitory activity of each compound was determined against T. cruzi and human DHFR. One of these compounds, ethyl 4-(5-[(2,4-diamino-6-quinazolinyl)methyl]amino-2-methoxyphenoxy)butanoate (6b) was co-crystallized with the bifunctional dihydrofolate reductase-thymidylate synthase enzyme of T. cruzi and the crystal structure of the ternary enzyme:cofactor:inhibitor complex was determined. Molecular docking was used to analyze the potential interactions of all inhibitors with T. cruzi DHFR and human DHFR. Inhibitory activities of these compounds are discussed in the light of enzyme-ligand interactions. Binding affinities of each inhibitor for the respective enzymes were calculated based on the experimental or docked binding mode. An estimated 60-70% of the total binding energy is contributed by the 2,4-diaminoquinazoline scaffold.

  7. Role of 5α-reductase inhibitors in androgen-stimulated skin disorders.

    Science.gov (United States)

    Azzouni, Faris; Zeitouni, Nathalie; Mohler, James

    2013-02-01

    5α-reductase (5α-R) isozymes are ubiquitously expressed in human tissues. This enzyme family is composed of 3 members that perform several important biologic functions. 5α-R isozymes play an important role in benign prostate hyperplasia, prostate cancer, and androgen-stimulated skin disorders, which include androgenic alopecia, acne, and hirsutism. Discovery of 5α-R type 2 deficiency in 1974 sparked interest in development of pharmaceutical agents to inhibit 5α-R isozymes, and 2 such inhibitors are currently available for clinical use: finasteride and dutasteride. 5α-R inhibitors are US Food and Drug Administration (FDA)-approved for the treatment of benign prostate hyperplasia. Only finasteride is FDA-approved for treatment of male androgenic alopecia. This article reviews the pathophysiology of androgen-stimulated skin disorders and the key clinical trials using 5α-R inhibitors in the treatment of androgen-stimulated skin disorders. PMID:23377402

  8. The HMG-CoA reductase inhibitor fluvastatin inhibits insect juvenile hormone biosynthesis.

    Science.gov (United States)

    Debernard, S; Rossignol, F; Couillaud, F

    1994-07-01

    Fluvastatin (Sandoz Compound XU 62-320), a synthetic HMG-CoA reductase inhibitor, was assayed in vitro and in vivo for its ability to suppress juvenile hormone (JH) biosynthesis by corpora allata of Locusta migratoria migratorioides. Fluvastatin inhibited JH biosynthesis by corpora allata in vitro. Exogenous mevalonic acid lactone restored JH biosynthesis in corpora allata inhibited by fluvastatin. Fluvastatin injected into locusts in vivo inhibited JH biosynthesis, but maximal inhibition lasted for only 6 hr. There were no discernible effects on either JH-regulated metamorphosis or oocyte maturation. Lengthening of the fourth larval stadium was observed and increased doses (single or repeated injections) were fatal. PMID:7926659

  9. 5-α reductase inhibitors, benign prostatic hyperplasia, and risk of male breast cancer

    OpenAIRE

    Robinson, David; Garmo, Hans; Holmberg, Lars; Stattin, Pär

    2015-01-01

    Purpose 5-α reductase inhibitors (5-ARI) have been suggested to increase the risk of male breast cancer. The aim of this study was to study the risk of breast cancer in men on 5-ARI, in men with benign prostatic hyperplasia (BPH) not on 5-ARI, and in men without BPH. Methods We performed a population-based cohort study in Sweden with data from The Prescribed Drug Register, The Patient Register, and The Cancer Register. Men on 5-ARI, men on α-blockers, or men who had undergone a transurethral ...

  10. 5-alpha reductase inhibitors, benign prostatic hyperplasia, and risk of male breast cancer

    OpenAIRE

    Robinson, David; Garmo, Hans; Holmberg, Lars; Stattin, Pär

    2015-01-01

    5-alpha reductase inhibitors (5-ARI) have been suggested to increase the risk of male breast cancer. The aim of this study was to study the risk of breast cancer in men on 5-ARI, in men with benign prostatic hyperplasia (BPH) not on 5-ARI, and in men without BPH. We performed a population-based cohort study in Sweden with data from The Prescribed Drug Register, The Patient Register, and The Cancer Register. Men on 5-ARI, men on alpha-blockers, or men who had undergone a transurethral resectio...

  11. Effect of 5-alpha Reductase Inhibitor on Storage Symptoms in Patients with Benign Prostatic Hyperplasia

    OpenAIRE

    Cho, Kang Jun; Kang, Se Hee; Kim, Hyo Sin; Koh, Jun Sung; Kim, Joon Chul

    2011-01-01

    Purpose Many patients with benign prostatic hyperplasia (BPH) have storage symptoms. The aim of this study was to evaluate the effects of treatment with a 5-alpha reductase inhibitor (5ARI) on storage symptoms in patients with BPH. Methods This study was conducted in 738 patients with lower urinary tract symptoms secondary to BPH. Patients with a prostate volume of higher than 30 mL on the transrectal ultrasound were classified into two groups: group A, in which an alpha blocker was solely ad...

  12. A structural account of substrate and inhibitor specificity differences between two Naphthol reductases

    Energy Technology Data Exchange (ETDEWEB)

    Liao, D.-I.; Thompson, J.E.; Fahnestock, S.; Valent, B.; Jordan, D.B. (DuPont)

    2010-03-08

    Two short chain dehydrogenase/reductases mediate naphthol reduction reactions in fungal melanin biosynthesis. An X-ray structure of 1,3,6,8-tetrahydroxynaphthalene reductase (4HNR) complexed with NADPH and pyroquilon was determined for examining substrate and inhibitor specificities that differ from those of 1,3,8-trihydroxynaphthalene reductase (3HNR). The 1.5 {angstrom} resolution structure allows for comparisons with the 1.7 {angstrom} resolution structure of 3HNR complexed with the same ligands. The sequences of the two proteins are 46% identical, and they have the same fold. The 30-fold lower affinity of the 4HNR-NADPH complex for pyroquilon (a commercial fungicide that targets 3HNR) in comparison to that of the 3HNR-NADPH complex can be explained by unfavorable interactions between the anionic carboxyl group of the C-terminal Ile282 of 4HNR and CH and CH{sub 2} groups of the inhibitor that are countered by favorable inhibitor interactions with 3HNR. 1,3,8-Trihydroxynaphthalene (3HN) and 1,3,6,8-tetrahydroxynaphthalene (4HN) were modeled onto the cyclic structure of pyroquilon in the 4HNR-NADPH-pyroquilon complex to examine the 300-fold preference of the enzyme for 4HN over 3HN. The models suggest that the C-terminal carboxyl group of Ile282 has a favorable hydrogen bonding interaction with the C6 hydroxyl group of 4HN and an unfavorable interaction with the C6 CH group of 3HN. Models of 3HN and 4HN in the 3HNR active site suggest a favorable interaction of the sulfur atom of the C-terminal Met283 with the C6 CH group of 3HN and an unfavorable one with the C6 hydroxyl group of 4HN, accounting for the 4-fold difference in substrate specificities. Thus, the C-terminal residues of the two naphthol reductase are determinants of inhibitor and substrate specificities.

  13. 5alpha-reductase inhibitors in benign prostatic hyperplasia and prostate cancer risk reduction.

    Science.gov (United States)

    Rittmaster, Roger S

    2008-04-01

    Androgens play an essential role in prostatic development and function, but are also involved in prostate disease pathogenesis. The primary prostatic androgen, dihydrotestosterone (DHT), is synthesized from testosterone by 5alpha-reductase types 1 and 2. Inhibition of the 5alpha-reductase isoenzymes therefore has potential therapeutic benefit in prostate disease. The two currently approved 5alpha-reductase inhibitors (5ARIs), finasteride and dutasteride, have demonstrated long-term efficacy and safety in the treatment of benign prostatic hyperplasia. Finasteride, a type-2 5ARI, has also been studied for its ability to reduce the incidence of biopsy-detectable prostate cancer in the Prostate Cancer Prevention Trial. Treatment with dutasteride, a dual 5ARI, has been shown to result in a greater degree and consistency of DHT suppression compared with finasteride. Two large-scale studies of dutasteride are currently investigating the role of near-maximal DHT suppression in the settings of prostate cancer risk reduction and expectant management of localized prostate cancer. PMID:18471794

  14. Identification of thioredoxin glutathione reductase inhibitors that kill cestode and trematode parasites.

    Directory of Open Access Journals (Sweden)

    Fabiana Ross

    Full Text Available Parasitic flatworms are responsible for serious infectious diseases that affect humans as well as livestock animals in vast regions of the world. Yet, the drug armamentarium available for treatment of these infections is limited: praziquantel is the single drug currently available for 200 million people infected with Schistosoma spp. and there is justified concern about emergence of drug resistance. Thioredoxin glutathione reductase (TGR is an essential core enzyme for redox homeostasis in flatworm parasites. In this work, we searched for flatworm TGR inhibitors testing compounds belonging to various families known to inhibit thioredoxin reductase or TGR and also additional electrophilic compounds. Several furoxans and one thiadiazole potently inhibited TGRs from both classes of parasitic flatworms: cestoda (tapeworms and trematoda (flukes, while several benzofuroxans and a quinoxaline moderately inhibited TGRs. Remarkably, five active compounds from diverse families possessed a phenylsulfonyl group, strongly suggesting that this moiety is a new pharmacophore. The most active inhibitors were further characterized and displayed slow and nearly irreversible binding to TGR. These compounds efficiently killed Echinococcus granulosus larval worms and Fasciola hepatica newly excysted juveniles in vitro at a 20 µM concentration. Our results support the concept that the redox metabolism of flatworm parasites is precarious and particularly susceptible to destabilization, show that furoxans can be used to target both flukes and tapeworms, and identified phenylsulfonyl as a new drug-hit moiety for both classes of flatworm parasites.

  15. Synergistic reduction of HIV-1 infectivity by 5-azacytidine and inhibitors of ribonucleotide reductase.

    Science.gov (United States)

    Rawson, Jonathan M O; Roth, Megan E; Xie, Jiashu; Daly, Michele B; Clouser, Christine L; Landman, Sean R; Reilly, Cavan S; Bonnac, Laurent; Kim, Baek; Patterson, Steven E; Mansky, Louis M

    2016-06-01

    Although many compounds have been approved for the treatment of human immunodeficiency type-1 (HIV-1) infection, additional anti-HIV-1 drugs (particularly those belonging to new drug classes) are still needed due to issues such as long-term drug-associated toxicities, transmission of drug-resistant variants, and development of multi-class resistance. Lethal mutagenesis represents an antiviral strategy that has not yet been clinically translated for HIV-1 and is based on the use of small molecules to induce excessive levels of deleterious mutations within the viral genome. Here, we show that 5-azacytidine (5-aza-C), a ribonucleoside analog that induces the lethal mutagenesis of HIV-1, and multiple inhibitors of the enzyme ribonucleotide reductase (RNR) interact in a synergistic fashion to more effectively reduce the infectivity of HIV-1. In these drug combinations, RNR inhibitors failed to significantly inhibit the conversion of 5-aza-C to 5-aza-2'-deoxycytidine, suggesting that 5-aza-C acts primarily as a deoxyribonucleoside even in the presence of RNR inhibitors. The mechanism of antiviral synergy was further investigated for the combination of 5-aza-C and one specific RNR inhibitor, resveratrol, as this combination improved the selectivity index of 5-aza-C to the greatest extent. Antiviral synergy was found to be primarily due to the reduced accumulation of reverse transcription products rather than the enhancement of viral mutagenesis. To our knowledge, these observations represent the first demonstration of antiretroviral synergy between a ribonucleoside analog and RNR inhibitors, and encourage the development of additional ribonucleoside analogs and RNR inhibitors with improved antiretroviral activity. PMID:27117260

  16. The REDUCE trial: chemoprevention in prostate cancer using a dual 5alpha-reductase inhibitor, dutasteride.

    Science.gov (United States)

    Musquera, Mireia; Fleshner, Neil E; Finelli, Antonio; Zlotta, Alexandre R

    2008-07-01

    Dutasteride, a dual 5alpha-reductase inhibitor, is used in the treatment of benign prostatic hyperplasia (BPH). It reduces serum prostate-specific antigen levels by approximately 50% at 6 months and total prostate volume by 25% after 2 years. Randomized placebo-controlled trials in BPH patients have shown the efficacy of dutasteride in symptomatic relief, improvements in quality of life and peak urinary flow rate. Side effects occurring with dutasteride are decreased libido, erectile dysfunction, ejaculation disorders and gynecomastia. Preliminary data from placebo-controlled BPH trials have shown a decrease in the detection of prostate cancer in patients treated with dutasteride, although these studies were not designed to look at this issue. Dutasteride differs from finasteride in that it inhibits both isoenzymes of 5alpha-reductase, type I and type II. The landmark Prostate Cancer Prevention Trial at the end of the 7-year study demonstrated a 24.8% reduction in the incidence of prostate cancer in the finasteride group compared with placebo. However, a 25.5% increase in the prevalence of high-grade Gleason tumors has been observed, the clinical significance of which has been debated. Preliminary data suggest a decrease in prostate cancer incidence in dutasteride-treated patients and demonstrate type I alphareductase enzyme expression in prostate cancer. As a result, dutasteride is being investigated for prostate cancer prevention in the ongoing Reduction by Dutasteride of Prostate Cancer Events (REDUCE) trial, which is discussed here. PMID:18588452

  17. Long-term Use of 5α-Reductase Inhibitors and the Risk of Male Breast Cancer.

    NARCIS (Netherlands)

    Duijnhoven, R.G.; Straus, S.M.J.M.; Souverein, P.C.; de Boer, A.; Bosch, J.L.H.R.; Hoes, A.W.; De Bruin, M.L.; Sub Pharmacoepidemiology; Dep Farmaceutische wetenschappen; Sub Pharmacotherapy, Theoretical

    2014-01-01

    Background The 5α-reductase inhibitors (5-ARI) finasteride and dutasteride are indicated for the treatment of lower urinary tract symptoms caused by benign prostatic hyperplasia. Case reports have suggested that 5-ARIs increase the risk for male breast cancer, with no conclusive evidence. The object

  18. Long-term use of 5α-reductase inhibitors and the risk of male breast cancer

    DEFF Research Database (Denmark)

    Duijnhoven, Ruben G; Straus, Sabine M J M; Souverein, Patrick C;

    2014-01-01

    BACKGROUND: The 5α-reductase inhibitors (5-ARI) finasteride and dutasteride are indicated for the treatment of lower urinary tract symptoms caused by benign prostatic hyperplasia. Case reports have suggested that 5-ARIs increase the risk for male breast cancer, with no conclusive evidence...

  19. New small-molecule inhibitors of dihydrofolate reductase inhibit Streptococcus mutans.

    Science.gov (United States)

    Zhang, Qiong; Nguyen, Thao; McMichael, Megan; Velu, Sadanandan E; Zou, Jing; Zhou, Xuedong; Wu, Hui

    2015-08-01

    Streptococcus mutans is a major aetiological agent of dental caries. Formation of biofilms is a key virulence factor of S. mutans. Drugs that inhibit S. mutans biofilms may have therapeutic potential. Dihydrofolate reductase (DHFR) plays a critical role in regulating the metabolism of folate. DHFR inhibitors are thus potent drugs and have been explored as anticancer and antimicrobial agents. In this study, a library of analogues based on a DHFR inhibitor, trimetrexate (TMQ), an FDA-approved drug, was screened and three new analogues that selectively inhibited S. mutans were identified. The most potent inhibitor had a 50% inhibitory concentration (IC50) of 454.0±10.2nM for the biofilm and 8.7±1.9nM for DHFR of S. mutans. In contrast, the IC50 of this compound for human DHFR was ca. 1000nM, a >100-fold decrease in its potency, demonstrating the high selectivity of the analogue. An analogue that exhibited the least potency for the S. mutans biofilm also had the lowest activity towards inhibiting S. mutans DHFR, further indicating that inhibition of biofilms is related to reduced DHFR activity. These data, along with docking of the most potent analogue to the modelled DHFR structure, suggested that the TMQ analogues indeed selectively inhibited S. mutans through targeting DHFR. These potent and selective small molecules are thus promising lead compounds to develop new effective therapeutics to prevent and treat dental caries. PMID:26022931

  20. Activity landscape analysis of novel 5[Formula: see text]-reductase inhibitors.

    Science.gov (United States)

    Naveja, J Jesús; Cortés-Benítez, Francisco; Bratoeff, Eugene; Medina-Franco, José L

    2016-08-01

    Inhibitors of the enzyme 5[Formula: see text]-reductase (5aR) are promising therapeutic agents for the treatment of benign prostatic hyperplasia (BPH) and prostate cancer. The lack of structural data of the enzyme 5aR prompts the application of ligand-based approaches to systematically explore the activity landscape of 5aR inhibitors. As part of an effort to develop inhibitors of this enzyme for the treatment of BPH, herein we discuss a chemoinformatic-based analysis of the activity landscape of a novel set of 53 novel pregnane and androstene compounds. It was found that, in general, for each pair of compounds in the set, as the structure similarity of the compounds increases the corresponding potency difference decreases. These results are in agreement with an overall smooth activity landscape. However, two potent activity cliff generators were identified pointing to specific small structural changes that have a large impact on the inhibition of 5aR. PMID:26829939

  1. Evaluation of Enoyl-Acyl Carrier Protein Reductase Inhibitors as Pseudomonas aeruginosa Quorum-Quenching Reagents

    Directory of Open Access Journals (Sweden)

    Søren Molin

    2010-02-01

    Full Text Available Pseudomonas aeruginosa is an opportunistic pathogen which is responsible for a wide range of infections. Production of virulence factors and biofilm formation by P. aeruginosa are partly regulated by cell-to-cell communication quorum-sensing systems. Identification of quorum-quenching reagents which block the quorum-sensing process can facilitate development of novel treatment strategies for P. aeruginosa infections. We have used molecular dynamics simulation and experimental studies to elucidate the efficiencies of two potential quorum-quenching reagents, triclosan and green tea epigallocatechin gallate (EGCG, which both function as inhibitors of the enoyl-acyl carrier protein (ACP reductase (ENR from the bacterial type II fatty acid synthesis pathway. Our studies suggest that EGCG has a higher binding affinity towards ENR of P. aeruginosa and is an efficient quorum-quenching reagent. EGCG treatment was further shown to be able to attenuate the production of virulence factors and biofilm formation of P. aeruginosa.

  2. Selenium-containing thioredoxin reductase inhibitor ethaselen sensitizes non-small cell lung cancer to radiotherapy.

    Science.gov (United States)

    Wang, Lei; Fu, Jia-Ning; Wang, Jing-Yu; Jin, Cun-Jing; Ren, Xiao-Yuan; Tan, Qiang; Li, Jing; Yin, Han-Wei; Xiong, Kun; Wang, Tian-Yu; Liu, Xin-Min; Zeng, Hui-Hui

    2011-09-01

    It has been proposed that thioredoxin reductase (TR) is a mediator that allows non-small cell lung cancer (NSCLC) to develop resistance to irradiation; however, little is known regarding the detailed mechanisms of action. Thus, ethaselen {1, 2-[bis (1,2-benzisoselenazolone-3 (2H)-ketone)] ethane, BBSKE}, a novel organoselenium TR inhibitor, is currently being investigated in a phase I clinical trial in China. However, its radiosensitizing effect remains unexplored. In this study, we found that the activity of TR increased dramatically in both A549 and H1299 cells after radiation, and moreover, could be inhibited by pretreatment with BBSKE (5 μmol/l). As a TR inhibitor, BBSKE enhanced the efficacy of radiation therapy both in vivo and in vitro without observable toxicity. BBSKE was found to suppress irradiation-induced NF-κB activation dramatically when using A549 cells stably transfected with NF-κB luciferase reporter. These results show the critical role of TR in the radioresistance of NSCLC and suggest that BBSKE is a potentially promising agent for the treatment of patients with NSCLC clinically. PMID:21562407

  3. Effects of aldose reductase inhibitor and vitamin B{sub 12} on myocardial uptake of I-123-MIBG in patients with non-insulin-dependent diabetes mellitus

    Energy Technology Data Exchange (ETDEWEB)

    Utsunomiya, Keita; Narabayashi, Isamu [Osaka Medical Coll., Takatsuki (Japan); Tamura, Koji; Nakaya, Yuko; Saika, Yoshinori; Kariyone, Shigeo; Ohnishi, Akira

    1998-04-01

    Based on the report that metaiodobenzylguanidine (MIBG) uptake into myocardial sympathetic nerve is useful for evaluation of diabetic heart sympathetic nerve dysfunction, authors examined the effects of epalrestat and vitamin B{sub 12} on the uptake. Subjects giving informed consent were 32 NIDDM patients without hypertensive or ischemic heart diseases on examination by {sup 201}Tl scintigraphy and others. At 10 min and 4 hr after intravenous injection of 111 MBq of {sup 123}I-MIBG, myocardial scintigraphy was performed to obtain the planar images with Siemens ZLC-370 gamma camera, whose data were processed by Shimadzu Scintipack 700 and evaluated by HM=early mean counts in heart (H)/early mean counts in mediastinum (M) and by %WR= (H-M)-(delayed H-delayed M) /(H-M). Epalrestat (150 mg/day) and vitamin B{sub 12} (1.5 mg/day) was given to each 16 patients for 3-5 months and {sup 123}I-MIBG scintigraphy was again carried out to calculate HM and %WR. As results, HM and %WR were not significantly changed by treatment with epalrestat but were improved with vitamin B{sub 12} significantly. (K.H.)

  4. LC-MS-MS Characterization of Forced Degradation Products of Fidarestat, a Novel Aldose Reductase Inhibitor: Development and Validation of a Stability-Indicating RP-HPLC Method.

    Science.gov (United States)

    Talluri, M V N Kumar; Khatoon, Lubna; Kalariya, Pradipbhai D; Chavan, Balasaheb B; Ragampeta, Srinivas

    2015-10-01

    An accurate, precise, robust and selective stability-indicating liquid chromatographic (LC) method has been developed for the monitoring of fidarestat in the presence of its forced degradants. The drug was subjected to hydrolysis (acid, alkali and neutral degradation), oxidation, photolysis and thermal stress conditions. The drug degraded significantly under hydrolytic (basic, acidic and neutral) and oxidative stress conditions, whereas it was found to be stable in photolytic and thermal conditions. The chromatographic separation was achieved on a Grace C18, (250 mm × 4.6 mm × 5 μm) column using gradient mobile phase system consisting of 10 mM of ammonium acetate buffer at pH 4 and acetonitrile at a flow rate of 1 mL/min with UV detection at 283 nm. The developed method was extended to liquid chromatography quadrupole time-of-flight tandem mass spectrometry (LC-QTOF-MS-MS) for characterization of all the degradation products. A total of five new degradation products were identified and characterized by LC-QTOF-MS-MS. The developed LC method was validated as per ICH guideline Q2 (R1). The proposed method was found to be successively applied for the quality control of fidarestat in bulk drug analysis. PMID:26014964

  5. Aldo-keto reductase 1B10 and its role in proliferation capacity of drug-resistant cancers

    Directory of Open Access Journals (Sweden)

    Toshiyuki eMatsunaga

    2012-01-01

    Full Text Available The human aldo-keto reductase AKR1B10, originally identified as an aldose reductase-like protein and human small intestine aldose reductase, is a cytosolic NADPH-dependent reductase that metabolizes a variety of endogenous compounds, such as aromatic and aliphatic aldehydes and dicarbonyl compounds, and some drug ketones. The enzyme is highly expressed in solid tumors of several tissues including lung and liver, and as such has received considerable interest as a relevant biomarker for the development of those tumors. In addition, AKR1B10 has been recently reported to be significantly up-regulated in some cancer cell lines (medulloblastoma D341 and colon cancer HT29 acquiring resistance towards chemotherapeutic agents (cyclophosphamide and mitomycin c, suggesting the validity of the enzyme as a chemoresistance marker. Although the detailed information on the AKR1B10-mediated mechanisms leading to the drug resistance process is not well understood so far, the enzyme has been proposed to be involved in functional regulations of cell proliferation and metabolism of drugs and endogenous lipids during the development of chemoresistance. This article reviews the current literature focusing mainly on expression profile and roles of AKR1B10 in the drug resistance of cancer cells. Recent developments of AKR1B10 inhibitors and their usefulness in restoring sensitivity to anticancer drugs are also reviewed.

  6. Side Effects Related to 5 α-Reductase Inhibitor Treatment of Hair Loss in Women: A Review.

    Science.gov (United States)

    Seale, Lauren R; Eglini, Ariana N; McMichael, Amy J

    2016-04-01

    5 α-reductase inhibitors such as finasteride and dutasteride have been studied for the treatment of hair loss in men, with finasteride being the only Food and Drug Administration-approved treatment. Increasingly, in recent years, off-label use of these drugs has been employed in the treatment of female pattern hair loss (FPHL) and frontal fibrosing alopecia (FFA) in women. Side effects with 5 α-reductase inhibitors can include changes in sexual function, and recent publications have characterized an increasing prevalence of these in men. A review of 20 peer-reviewed articles found that very few side effects, or adverse events, related to sexual function have been reported in studies in which dutasteride or finasteride has been used to treat hair loss in women. Future publications should investigate not only the efficacy of these drugs in treating FPHL and FFA, but the side effect profile in patients as well. PMID:27050696

  7. Cost Effectiveness of 5-Alpha Reductase Inhibitors for the Prevention of Prostate Cancer in Multiple Patient Populations

    OpenAIRE

    Stephanie R. Earnshaw; McDade, Cheryl L; Libby K. Black; Christopher F. Bell; Kattan, Michael W.

    2010-01-01

    Background: Although 5-alpha reductase inhibitors (5ARIs) have demonstrated that they reduce the risk of prostate cancer (PCa), they have not demonstrated cost effectiveness in the patient populations in which they have been examined. Objective: A decision-analytic model was created to explore economic benefits from a third-party payer perspective of the use of 5ARIs in preventing PCa in men with different risk factors for developing the disease. Methods: A Markov model was developed to simul...

  8. Growth of LAPC4 prostate cancer xenograft tumor is insensitive to 5α-reductase inhibitor dutasteride

    OpenAIRE

    Garcia, Raquel Ramos; Masoodi, Khalid Z.; Pascal, Laura E.; Nelson, Joel B.; Wang, Zhou

    2014-01-01

    Intermittent androgen deprivation therapy (IADT) allows prostate cancer patients a break from the side-effects of continuous androgen deprivation therapy (ADT). Although clinical studies suggest that IADT can significantly improve patient quality of life over ADT, it has not been demonstrated to improve patient survival. Recently, increased survival has been demonstrated when 5α-reductase inhibitors have been used during the off-cycle of IADT in animal xenograft tumor models LNCaP and LuCaP35...

  9. Five-alpha Reductase Inhibitor Influences Expression of Androgen Receptor and HOXB13 in Human Hyperplastic Prostate Tissue

    OpenAIRE

    Chaeyong Jung; Youngwoong Park; Young-Rang Kim; Soo Bang Ryu; Taek Won Kang

    2013-01-01

    Objectives Five-alpha reductase inhibitors (5ARIs) are known as chemopreventive agents in prostate cancer with a risk of high-grade disease. This study evaluated the effects of 5ARI on androgen receptor (AR) and proteins involved in prostate cell growth such as HOXB13 expression in human prostate tissue and LNCaP prostate cancer cells. Materials and Methods We retrospectively selected 21 patients who underwent TURP between March 2007 and February 2010 for previously confirmed BPH by prostate...

  10. Risk of Fractures and Falls during and after 5-α Reductase Inhibitor Use: A Nationwide Cohort Study

    OpenAIRE

    Robinson, David; Garmo, Hans; Stattin, Pär; Michaëlsson, Karl

    2015-01-01

    BACKGROUND: Lower urinary tract symptoms are common among older men and 5-α reductase inhibitors (5-ARI) are a group of drugs recommended in treating these symptoms. The effect on prostate volume is mediated by a reduction in dihydrotestosterone; however, this reduction is counterbalanced by a 25% rise in serum testosterone levels. Therefore, 5-ARI use might have systemic effects and differentially affect bone mineral density, muscular mass and strength, as well as falls, all of which are maj...

  11. Discrimination of Potent Inhibitors of Toxoplasma gondii Enoyl-Acyl Carrier Protein Reductase by Thermal Shift Assay

    OpenAIRE

    Afanador, Gustavo A.; Muench, Stephen P.; McPhillie, Martin; Fomovska, Alina; Schön, Arne; Zhou, Ying; Cheng, Gang; Stec, Jozef; Freundlich, Joel S.; Shieh, Hong-Ming; Anderson, John W.; Jacobus, David P.; Fidock, David A.; Kozikowski, Alan P.; Fishwick, Colin W.

    2013-01-01

    Many microbial pathogens rely on a type II fatty acid synthesis (FASII) pathway which is distinct from the type I pathway found in humans. Enoyl-Acyl Carrier Protein Reductase (ENR) is an essential FASII pathway enzyme and the target of a number of antimicrobial drug discovery efforts. The biocide triclosan is established as a potent inhibitor of ENR and has been the starting point for medicinal chemistry studies. We evaluated a series of triclosan analogs for their ability to inhibit the gro...

  12. Benefit–risk assessment of HMG-CoA reductase inhibitors (statins): a discrete choice experiment

    Science.gov (United States)

    Sornlertlumvanich, Korn; Ngorsuraches, Surachat

    2016-01-01

    Objectives To conduct the benefit–risk assessment of 3-hydroxy-3-methyl-glutaryl (HMG) coenzyme A reductase inhibitors (statins) using a discrete choice experiment, based on 3 major stakeholders’ perspectives including patients, experts and policymakers in Thailand. Design A discrete choice experiment questionnaire survey in three stakeholders’ perspectives. Setting Public hospitals in Thailand. Participants A total of 353 policymakers, experts and patients. Outcomes Stakeholders’ preferences for assessment criteria (stroke reduction, myocardial infarction reduction, myalgia and hepatotoxicity). Statins’ ranking and maximum acceptable risk in all perspectives were also calculated. Results For any perspective, the most and least important criteria were the risk of hepatotoxicity and the benefit of myocardial infarction reduction, respectively. Patients and experts agreed on the order of importance for myalgia and stroke reduction, but policymakers had different order of importance in these criteria. Overall, results showed that the highest and lowest chances of being chosen were atorvastatin and rosuvastatin, respectively. Only patients’ ranking order was different from others. Maximum acceptable risk of hepatotoxicity was lower than that of myalgia, reflecting the greater concern of all perspectives to statin consequence on liver. Conclusions The results of benefit–risk assessment from every perspective were somewhat consistent. This study demonstrated the feasibility of applying a discrete choice experiment in the benefit–risk assessment of drugs and encouraged the engagement of multiple stakeholders in the decision-making process. PMID:26916689

  13. 5-α reductase inhibitors and prostate cancer prevention: where do we turn now?

    Directory of Open Access Journals (Sweden)

    Hamilton Robert J

    2011-09-01

    Full Text Available Abstract With the lifetime risk of being diagnosed with prostate cancer so great, an effective chemopreventive agent could have a profound impact on the lives of men. Despite decades of searching for such an agent, physicians still do not have an approved drug to offer their patients. In this article, we outline current strategies for preventing prostate cancer in general, with a focus on the 5-α-reductase inhibitors (5-ARIs finasteride and dutasteride. We discuss the two landmark randomized, controlled trials of finasteride and dutasteride, highlighting the controversies stemming from the results, and address the issue of 5-ARI use, including reasons why providers may be hesitant to use these agents for chemoprevention. We further discuss the recent US Food and Drug Administration ruling against the proposed new indication for dutasteride and the change to the labeling of finasteride, both of which were intended to permit physicians to use the drugs for chemoprevention. Finally, we discuss future directions for 5-ARI research.

  14. Current status of 5α-reductase inhibitors in prostate disease management.

    Science.gov (United States)

    Kang, Dong Il; Chung, Jae Il

    2013-04-01

    The key enzyme in the androgen synthesis and androgen receptor pathways is 5α-reductase (5-AR), which occurs as three isoenzymes. Types I and II 5-ARs the most important clinically, and two different 5-AR inhibitors (5-ARIs), finasteride and dutasteride, have been developed. Several urology associations have recommended and upgraded the use of 5-ARIs for an enlarged prostate with lower urinary tract symptoms. In the Prostate Cancer Prevention Trial and the Reduction by Dutasteride of Prostate Cancer Events Trial, 5-ARIs reduced the incidence of low-grade prostate cancer. However, despite the documented reductions in the overall incidence of prostate cancer, 5-ARIs are at the center of a dispute. The American Society of Clinical Oncology (ASCO) and the American Urology Association (AUA) presented clinical guidelines for the use of 5-ARIs for chemoprevention of prostate cancer in 2008. However, ASCO/AUA has eliminated these from the main "Clinical Guidelines" in 2012, because the U.S. Food and Drug Administration denied a supplemental New Drug Application for the use of dutasteride for prostate cancer chemoprevention. The 5-ARIs can also be used to manage hemospermia and prostatic hematuria, and to prevent intraoperative bleeding, although there is insufficient evidence for a standard strategy. This review summarizes the current use of 5-ARIs for prostate disease, including benign prostate hyperplasia, prostate cancer, prostate-related bleeding, and hemospermia. PMID:23614056

  15. 5-α reductase inhibitors and prostate cancer prevention: where do we turn now?

    Science.gov (United States)

    Hamilton, Robert J; Freedland, Stephen J

    2011-01-01

    With the lifetime risk of being diagnosed with prostate cancer so great, an effective chemopreventive agent could have a profound impact on the lives of men. Despite decades of searching for such an agent, physicians still do not have an approved drug to offer their patients. In this article, we outline current strategies for preventing prostate cancer in general, with a focus on the 5-α-reductase inhibitors (5-ARIs) finasteride and dutasteride. We discuss the two landmark randomized, controlled trials of finasteride and dutasteride, highlighting the controversies stemming from the results, and address the issue of 5-ARI use, including reasons why providers may be hesitant to use these agents for chemoprevention. We further discuss the recent US Food and Drug Administration ruling against the proposed new indication for dutasteride and the change to the labeling of finasteride, both of which were intended to permit physicians to use the drugs for chemoprevention. Finally, we discuss future directions for 5-ARI research. PMID:21920036

  16. Effects of HMG-CoA Reductase Inhibitors (Statins On Bone Mineral Density and Metabolism

    Directory of Open Access Journals (Sweden)

    Nehir Samancı

    2004-06-01

    Full Text Available Hydroxy methylglutaryl coenzyme A reductase inhibitors (statins have been shown to have effects on bone metabolism in laboratory studies. While early clinic studies have showed lower risk for osteoporotic fractures among statin users than nonusers, subsequent studies have found mixed results. The purpose of this study was to investigate the effects of statins on bone mineral density (BMD and bone metabolism. Thirty-five consecutive postmenopausal hypercholesterolemic women who were treated for at least last 6 months with statins were included in the study. Seventy-five normocholesterolemic age-matched postmenopausal women were in the control group. Subjects with a history of any diseases and used drugs that may affect calcium or bone metabolism were excluded from the study. Age, associated illness, years since menopause, and body mass index (BMI were obtained from all the patients including the control group. Besides, serum calcium, phosphate, alkaline phosphates, parathyroid hormone, 25 hydroxy D3, osteocalcin, and urinary calcium excretion were measured. BMD was measured by using dual-energy x-ray absorptiometry (DEXA at femoral neck and 3rd lomber spine. Mean duration of statin use was 28.17±21.17 months. BMI was found to be statistically higher in statin users than nonusers (27.47±3.67kg/m2 and 25.46±3.91 kg/m2, respectively. The markers of bone metabolism used in the study were found to be similar between the groups. BMD was not different in statin users and nonusers at femoral neck and lomber spine. As conclusion, statin use did not affect BMD and bone metabolism in this study. In our opinion large randomised, controlled, prospective clinical trials are needed to accurately determine the role of statins in the treatment of osteoporosis.

  17. 5-Alpha reductase inhibitor use and prostate cancer survival in the Finnish Prostate Cancer Screening Trial.

    Science.gov (United States)

    Murtola, Teemu J; Karppa, Elina K; Taari, Kimmo; Talala, Kirsi; Tammela, Teuvo Lj; Auvinen, Anssi

    2016-06-15

    Randomized clinical trials have shown that use of 5α-reductase inhibitors (5-ARIs) lowers overall prostate cancer (PCa) risk compared to placebo, while the proportion of Gleason 8-10 tumors is elevated. It is unknown whether this affects PCa-specific survival. We studied disease-specific survival by 5-ARI usage in a cohort of 6,537 prostate cancer cases diagnosed in the Finnish Prostate Cancer Screening Trial and linked to the national prescription database for information on medication use. Cox proportional hazards regression was used to estimate hazard ratios and 95% confidence intervals for prostate cancer-specific deaths. For comparison, survival among alpha-blocker users was also evaluated. During the median follow-up of 7.5 years after diagnosis a total of 2,478 men died; 617 due to prostate cancer and 1,861 due to other causes. The risk of prostate cancer death did not differ between 5-ARI users and nonusers (multivariable adjusted HR 0.94, 95% CI 0.72-1.24 and HR 0.98, 95% CI 0.69-1.41 for usage before and after the diagnosis, respectively). Alpha-blocker usage both before and after diagnosis was associated with increased risk of prostate cancer death (HR 1.29, 95% CI 1.08-1.54 and HR 1.56, 95% CI 1.30-1.86, respectively). The risk increase vanished in long-term alpha-blocker usage. Use of 5-ARIs does not appear to affect prostate cancer mortality when used in management of benign prostatic hyperplasia. Increased risk associated with alpha-blocker usage should prompt further exploration on the prognostic role of lower urinary tract symptoms. PMID:26804670

  18. Molecular pharmacology and antitumor activity of palmarumycin based inhibitors of thioredoxin reductase.

    OpenAIRE

    Powis, Garth; Wipf, Peter; Lynch, Stephen M.; Birmingham, Anne; Kirkpatrick, D. Lynn

    2006-01-01

    The cytosolic thioredoxin (Trx) redox system comprising Trx-1 and the NADPH dependent thioredoxin reductase -1 reductase (TrxR-1) is an important regulator of cell growth and survival. Trx-1 is overexpressed in many human tumors where it is associated with increased cell proliferation, decreased apoptosis and decreased patient survival. We hypothesized that TrxR-1 provides a target to inhibit the activity of overexpressed Trx-1 for the development of novel anticancer agents. We found that the...

  19. Probing the Active Site of Candida Glabrata Dihydrofolate Reductase with High Resolution Crystal Structures and the Synthesis of New Inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, J.; Bolstad, D; Smith, A; Priestley, N; Wright, D; Anderson, A

    2009-01-01

    Candida glabrata, a fungal strain resistant to many commonly administered antifungal agents, has become an emerging threat to human health. In previous work, we validated that the essential enzyme, dihydrofolate reductase, is a drug target in C. glabrata. Using a crystal structure of dihydrofolate reductase from C. glabrata bound to an initial lead compound, we designed a class of biphenyl antifolates that potently and selectively inhibit both the enzyme and the growth of the fungal culture. In this work, we explore the structure-activity relationships of this class of antifolates with four new high resolution crystal structures of enzyme:inhibitor complexes and the synthesis of four new inhibitors. The designed inhibitors are intended to probe key hydrophobic pockets visible in the crystal structure. The crystal structures and an evaluation of the new compounds reveal that methyl groups at the meta and para positions of the distal phenyl ring achieve the greatest number of interactions with the pathogenic enzyme and the greatest degree of selectivity over the human enzyme. Additionally, antifungal activity can be tuned with substitution patterns at the propargyl and para-phenyl positions.

  20. Hepatoselectivity of statins: design and synthesis of 4-sulfamoyl pyrroles as HMG-CoA reductase inhibitors.

    Science.gov (United States)

    Park, William K C; Kennedy, Robert M; Larsen, Scott D; Miller, Steve; Roth, Bruce D; Song, Yuntao; Steinbaugh, Bruce A; Sun, Kevin; Tait, Bradley D; Kowala, Mark C; Trivedi, Bharat K; Auerbach, Bruce; Askew, Valerie; Dillon, Lisa; Hanselman, Jeffrey C; Lin, Zhiwu; Lu, Gina H; Robertson, Andrew; Sekerke, Catherine

    2008-02-01

    4-Sulfamoyl pyrroles were designed as novel hepatoselective HMG-CoA reductase inhibitors (statins) to reduce myalgia, a statin-induced adverse effect. The compounds were prepared via a [3+2] cycloaddition of a Münchnone with a sulfonamide-substituted alkyne. We identified compounds with greater selectivity for hepatocytes compared to L6-myocytes than rosuvastatin and atorvastatin. There was an inverse correlation of myocyte potencies and ClogP values. A number of analogs were effective at reducing cholesterol in acute and chronic in vivo models but they lacked sufficient chronic in vivo activity to warrant further development. PMID:18155906

  1. Thioredoxin reductase inhibitor auranofin prevents membrane transport of diphtheria toxin into the cytosol and protects human cells from intoxication.

    Science.gov (United States)

    Schnell, Leonie; Dmochewitz-Kück, Lydia; Feigl, Peter; Montecucco, Cesare; Barth, Holger

    2016-06-15

    During cellular uptake, diphtheria toxin delivers its catalytic domain DTA from acidified endosomes into the cytosol, which requires reduction of the disulfide linking DTA to the transport domain. In vitro, thioredoxin reduces this disulfide and thioredoxin reductase (TrxR) is part of a cytosolic complex facilitating DTA-translocation. We found that the TrxR-specific inhibitor auranofin prevented DTA delivery into the cytosol and intoxication of HeLa cells with diphtheria toxin, offering perspectives for novel pharmacological strategies against diphtheria. PMID:25911959

  2. Thermodynamic and Structure Guided Design of Statin Based Inhibitors of 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase

    Energy Technology Data Exchange (ETDEWEB)

    Sarver, Ronald W.; Bills, Elizabeth; Bolton, Gary; Bratton, Larry D.; Caspers, Nicole L.; Dunbar, James B.; Harris, Melissa S.; Hutchings, Richard H.; Kennedy, Robert M.; Larsen, Scott D.; Pavlovsky, Alexander; Pfefferkorn, Jeffrey A.; Bainbridge, Graeme (Pfizer)

    2008-10-02

    Clinical studies have demonstrated that statins, 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) inhibitors, are effective at lowering mortality levels associated with cardiovascular disease; however, 2--7% of patients may experience statin-induced myalgia that limits compliance with a treatment regimen. High resolution crystal structures, thermodynamic binding parameters, and biochemical data were used to design statin inhibitors with improved HMGR affinity and therapeutic index relative to statin-induced myalgia. These studies facilitated the identification of imidazole 1 as a potent (IC{sub 50} = 7.9 nM) inhibitor with excellent hepatoselectivity (>1000-fold) and good in vivo efficacy. The binding of 1 to HMGR was found to be enthalpically driven with a {Delta}H of -17.7 kcal/M. Additionally, a second novel series of bicyclic pyrrole-based inhibitors was identified that induced order in a protein flap of HMGR. Similar ordering was detected in a substrate complex, but has not been reported in previous statin inhibitor complexes with HMGR.

  3. Aldo keto reductases 1B in endocrinology and metabolism

    Directory of Open Access Journals (Sweden)

    AntoineMartinez

    2012-08-01

    Full Text Available The aldose reductase (human AKR1B1/mouse Akr1b3 has been the focus of many research because of its role in diabetic complications. The starting point of these alterations is the massive entry of glucose in polyol pathway where it is converted into sorbitol by this enzyme. However, the issue of aldose reductase function in non-diabetic condition remains unresolved. Aldose reductase-like enzymes (AKR1B10, Akr1b7 and Akr1b8 are highly related isoforms often co-expressed with bona fide aldose reductase, making functional analysis of one or the other isoform a challenging task. AKR1B/Akr1b members share at least 65% protein identity and the general ability to reduce many redundant substrates such as aldehydes provided from lipid peroxidation, steroids and their by-products and xenobiotics in vitro. Based on these properties, AKR1B/Akr1b are generally considered as detoxifying enzymes. Considering that divergences should be more informative than similarities to help understanding their physiological functions, we chose to review specific hallmarks of each human/mouse isoforms by focusing on tissue distribution and specific mechanisms of gene regulation. Indeed, although the aldose reductase shows ubiquitous expression, aldose reductase-like proteins exhibit tissue-specific patterns of expression. We focused on 3 organs where certain isoforms are enriched, the adrenal gland, enterohepatic and adipose tissues and tried to connect recent enzymatic and regulation data with endocrine and metabolic functions of these organs. We presented recent mouse models showing unsuspected physiological functions in the regulation of glucido-lipidic metabolism and adipose tissue homeostasis. Beyond the widely accepted idea that AKR1B/Akr1b are detoxification enzymes, these recent reports provide growing evidences that they are able to modify or generate signal molecules. This conceptually shifts this class of enzymes from unenviable status of scavenger to upper class of

  4. Exploration of natural product ingredients as inhibitors of human HMG-CoA reductase through structure-based virtual screening

    Directory of Open Access Journals (Sweden)

    Lin SH

    2015-06-01

    Full Text Available Shih-Hung Lin,1 Kao-Jean Huang,1,2 Ching-Feng Weng,1 David Shiuan1 1Department of Life Science and Institute of Biotechnology, National Dong Hwa University, Hualien, Taiwan, Republic of China; 2Development Center of Biotechnology, Taipei, Taiwan, Republic of China Abstract: Cholesterol plays an important role in living cells. However, a very high level of cholesterol may lead to atherosclerosis. HMG-CoA (3-hydroxy-3-methylglutaryl coenzyme A reductase is the key enzyme in the cholesterol biosynthesis pathway, and the statin-like drugs are inhibitors of human HMG-CoA reductase (hHMGR. The present study aimed to virtually screen for potential hHMGR inhibitors from natural product to discover hypolipidemic drug candidates with fewer side effects and lesser toxicities. We used the 3D structure 1HWK from the PDB (Protein Data Bank database of hHMGR as the target to screen for the strongly bound compounds from the traditional Chinese medicine database. Many interesting molecules including polyphenolic compounds, polisubstituted heterocyclics, and linear lipophilic alcohols were identified and their ADMET (absorption, disrtibution, metabolism, excretion, toxicity properties were predicted. Finally, four compounds were obtained for the in vitro validation experiments. The results indicated that curcumin and salvianolic acid C can effectively inhibit hHMGR, with IC50 (half maximal inhibitory concentration values of 4.3 µM and 8 µM, respectively. The present study also demonstrated the feasibility of discovering new drug candidates through structure-based virtual screening. Keywords: HMG-CoA reductase, virtual screening, curcumin, salvianolic acid C

  5. A Rational Approach to Identify Inhibitors of Mycobacterium tuberculosis Enoyl Acyl Carrier Protein Reductase

    Czech Academy of Sciences Publication Activity Database

    Chhabria, M. T.; Parmar, K. B.; Brahmkshatriya, Pathik

    2013-01-01

    Roč. 19, č. 21 (2013), s. 3878-3883. ISSN 1381-6128 Institutional support: RVO:61388963 Keywords : mycobacterium tuberculosis * enoyl acyl carrier protein reductase * pharmacophore modeling * molecular docking * binding interactions Subject RIV: FR - Pharmacology ; Medidal Chemistry Impact factor: 3.288, year: 2013

  6. Design, synthesis, and biological evaluation of resveratrol analogues as aromatase and quinone reductase 2 inhibitors for chemoprevention of cancer

    International Nuclear Information System (INIS)

    A series of new resveratrol analogues were designed and synthesized and their inhibitory activities against aromatase were evaluated. The crystal structure of human aromatase (PDB 3eqm) was used to rationalize the mechanism of action of the aromatase inhibitor 32 (IC50 0.59 μM) through docking, molecular mechanics energy minimization, and computer graphics molecular modeling, and the information was utilized to design several very potent inhibitors, including compounds 82 (IC50 70 nM) and 84 (IC50 36 nM). The aromatase inhibitory activities of these compounds are much more potent than that for the lead compound resveratrol, which has an IC50 of 80 μM. In addition to aromatase inhibitory activity, compounds 32 and 44 also displayed potent QR2 inhibitory activity (IC50 1.7 μM and 0.27 μM, respectively) and the high-resolution X-ray structures of QR2 in complex with these two compounds provide insight into their mechanism of QR2 inhibition. The aromatase and quinone reductase inhibitors resulting from these studies have potential value in the treatment and prevention of cancer.

  7. Pyrithione-based ruthenium complexes as inhibitors of aldo-keto reductase 1C enzymes and anticancer agents.

    Science.gov (United States)

    Kljun, Jakob; Anko, Maja; Traven, Katja; Sinreih, Maša; Pavlič, Renata; Peršič, Špela; Ude, Žiga; Codina, Elisa Esteve; Stojan, Jure; Lanišnik Rižner, Tea; Turel, Iztok

    2016-08-01

    Four ruthenium complexes of clinically used zinc ionophore pyrithione and its oxygen analog 2-hydroxypyridine N-oxide were prepared and evaluated as inhibitors of enzymes of the aldo-keto reductase subfamily 1C (AKR1C). A kinetic study assisted with docking simulations showed a mixed type of inhibition consisting of a fast reversible and a slow irreversible step in the case of both organometallic compounds 1A and 1B. Both compounds also showed a remarkable selectivity towards AKR1C1 and AKR1C3 which are targets for breast cancer drug design. The organoruthenium complex of ligand pyrithione as well as pyrithione itself also displayed toxicity on the hormone-dependent MCF-7 breast cancer cell line with EC50 values in the low micromolar range. PMID:27357845

  8. Adverse reactions of HMG—CoA reductase inhibitors as a consequence of drug—drug interaction

    Institute of Scientific and Technical Information of China (English)

    IkedaT

    2002-01-01

    Use of HMG-CoA reductase inhibitors in treating hypercholesterolemia is a well-established therapy.Presently,atorvastatin,fluvastatin,lovastatin,simvastatin and pravastatin are used clinically.Cerivastatin was pulled from the market in 2001 due to its higher risk of inducing rhabdomyolysis than all other drugs.Hepatotoxicity and rhabdomyolysis are the known adverse reactions by these drugs.However,the hepatotoxicity has been regarded to be mild,and is now referred to as transaminitis.Rhadomyolysis occurs in rare instances but is sometimes life threatening as a result of renal failure caused by myoglobinemia.The mechanism leading to rhabdomyolysis is unknown but in many of the reported cases,increased plasma concentratinos of thes drugs have been observed,most likely as a consequence of drug interaction.Inhibition of CYP 3A4 and UGT is believed to be the reason for this interaction.

  9. GRE2 from Scheffersomyces stipitis as an aldehyde reductase contributes tolerance to aldehyde inhibitors derived from lignocellulosic biomass.

    Science.gov (United States)

    Wang, Xu; Ma, Menggen; Liu, Z Lewis; Xiang, Quanju; Li, Xi; Liu, Na; Zhang, Xiaoping

    2016-08-01

    Scheffersomyces (Pichia) stipitis is one of the most promising yeasts for industrial bioethanol production from lignocellulosic biomass. S. stipitis is able to in situ detoxify aldehyde inhibitors (such as furfural and 5-hydroxymethylfurfural (HMF)) to less toxic corresponding alcohols. However, the reduction enzymes involved in this reaction remain largely unknown. In this study, we reported that an uncharacterized open reading frame PICST_72153 (putative GRE2) from S. stipitis was highly induced in response to furfural and HMF stresses. Overexpression of this gene in Saccharomyces cerevisiae improved yeast tolerance to furfural and HMF. GRE2 was identified as an aldehyde reductase which can reduce furfural to FM with either NADH or NADPH as the co-factor and reduce HMF to FDM with NADPH as the co-factor. This enzyme can also reduce multiple aldehydes to their corresponding alcohols. Amino acid sequence analysis indicated that it is a member of the subclass "intermediate" of the short-chain dehydrogenase/reductase (SDR) superfamily. Although GRE2 from S. stipitis is similar to GRE2 from S. cerevisiae in a three-dimensional structure, some differences were predicted. GRE2 from S. stipitis forms loops at D133-E137 and T143-N145 locations with two α-helices at E154-K157 and E252-A254 locations, different GRE2 from S. cerevisiae with an α-helix at D133-E137 and a β-sheet at T143-N145 locations, and two loops at E154-K157 and E252-A254 locations. This research provided guidelines for the study of other SDR enzymes from S. stipitis and other yeasts on tolerant mechanisms to aldehyde inhibitors derived from lignocellulosic biomass. PMID:27003269

  10. X-ray structural studies of quinone reductase 2 nanomolar range inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Pegan, Scott D.; Sturdy, Megan; Ferry, Gilles; Delagrange, Philippe; Boutin, Jean A.; Mesecar, Andrew D. (IdRS); (Purdue); (Colorado); (UIC)

    2011-09-06

    Quinone reductase 2 (QR2) is one of two members comprising the mammalian quinone reductase family of enzymes responsible for performing FAD mediated reductions of quinone substrates. In contrast to quinone reductase 1 (QR1) which uses NAD(P)H as its co-substrate, QR2 utilizes a rare group of hydride donors, N-methyl or N-ribosyl nicotinamide. Several studies have linked QR2 to the generation of quinone free radicals, several neuronal degenerative diseases, and cancer. QR2 has been also identified as the third melatonin receptor (MT3) through in cellulo and in vitro inhibition of QR2 by traditional MT3 ligands, and through recent X-ray structures of human QR2 (hQR2) in complex with melatonin and 2-iodomelatonin. Several MT3 specific ligands have been developed that exhibit both potent in cellulo inhibition of hQR2 nanomolar, affinity for MT3. The potency of these ligands suggest their use as molecular probes for hQR2. However, no definitive correlation between traditionally obtained MT3 ligand affinity and hQR2 inhibition exists limiting our understanding of how these ligands are accommodated in the hQR2 active site. To obtain a clearer relationship between the structures of developed MT3 ligands and their inhibitory properties, in cellulo and in vitro IC{sub 50} values were determined for a representative set of MT3 ligands (MCA-NAT, 2-I-MCANAT, prazosin, S26695, S32797, and S29434). Furthermore, X-ray structures for each of these ligands in complex with hQR2 were determined allowing for a structural evaluation of the binding modes of these ligands in relation to the potency of MT3 ligands.

  11. Caracemide, a site-specific irreversible inhibitor of protein R1 of Escherichia coli ribonucleotide reductase

    DEFF Research Database (Denmark)

    Larsen, I. K.; Cornett, Claus; Karlsson, M.; Sahlin, M.; Sjoberg, B. M.

    1992-01-01

    The anticancer drug caracemide, N-acetyl-N,O-di(methylcarbamoyl)hydroxylamine, and one of its degradation products, N-acetyl-O-methylcarbamoyl-hydroxylamine, were found to inhibit the enzyme ribonucleotide reductase of Escherichia coli by specific interaction with its larger component protein R1...... caracemide inactivation. These results indicate that caracemide inactivates R1 by covalent modification at the substrate-binding site. By analogy with the known interaction between caracemide and acetylcholinesterase or choline acetyltransferase, we propose that the modification of R1 occurs at an activated...... cysteine or serine residue in the active site of the enzyme....

  12. Repositioning of a cyclin-dependent kinase inhibitor GW8510 as a ribonucleotide reductase M2 inhibitor to treat human colorectal cancer.

    Science.gov (United States)

    Hsieh, Y-Y; Chou, C-J; Lo, H-L; Yang, P-M

    2016-01-01

    Colorectal cancer (CRC) is the second leading cause of cancer-related death in males and females in the world. It is of immediate importance to develop novel therapeutics. Human ribonucleotide reductase (RRM1/RRM2) has an essential role in converting ribonucleoside diphosphate to 2'-deoxyribonucleoside diphosphate to maintain the homeostasis of nucleotide pools. RRM2 is a prognostic biomarker and predicts poor survival of CRC. In addition, increased RRM2 activity is associated with malignant transformation and tumor cell growth. Bioinformatics analyses show that RRM2 was overexpressed in CRC and might be an attractive target for treating CRC. Therefore, we attempted to search novel RRM2 inhibitors by using a gene expression signature-based approach, connectivity MAP (CMAP). The result predicted GW8510, a cyclin-dependent kinase inhibitor, as a potential RRM2 inhibitor. Western blot analysis indicated that GW8510 inhibited RRM2 expression through promoting its proteasomal degradation. In addition, GW8510 induced autophagic cell death. In addition, the sensitivities of CRC cells to GW8510 were associated with the levels of RRM2 and endogenous autophagic flux. Taken together, our study indicates that GW8510 could be a potential anti-CRC agent through targeting RRM2. PMID:27551518

  13. Modulation of Aldose Reductase Inhibition by Halogen Bond Tuning

    Czech Academy of Sciences Publication Activity Database

    Fanfrlík, Jindřich; Kolář, Michal; Kamlar, M.; Hurný, D.; Ruiz, F. X.; Cousido-Siah, A.; Mitschler, A.; Řezáč, Jan; Munusamy, E.; Lepšík, Martin; Matějíček, P.; Veselý, J.; Podjarny, A.; Hobza, Pavel

    2013-01-01

    Roč. 8, č. 11 (2013), s. 2484-2492. ISSN 1554-8929 R&D Projects: GA ČR GBP208/12/G016 Grant ostatní: Operational Program Research and Development for Innovations(XE) CZ 1.05/2.1.00/03/0058 Institutional support: RVO:61388963 Keywords : force-field * drug design * noncovalent complexes Subject RIV: CE - Biochemistry Impact factor: 5.356, year: 2013

  14. Intracellular signal transduction of PBAN action in lepidopteran insects: inhibition of sex pheromone production by compactin, an HMG CoA reductase inhibitor.

    Science.gov (United States)

    Ozawa, R; Matsumoto, S; Kim, G H; Uchiumi, K; Kurihara, M; Shono, T; Mitsui, T

    1995-06-27

    Pheromone biosynthesis activating neuropeptide (PBAN) regulates sex pheromone production in the pheromone glands of many species of female moths. In order to probe the biochemical steps as well as underlying mechanisms regulated by PBAN, we have tested the effect of chemicals on sex pheromone production by using an in vitro assay. Among the chemicals we tested here, compactin, a specific 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitor, clearly inhibited the pheromone biosynthesis in the silkworm, Bombyx mori, and the common cutworm, Spodoptera litura. Since the activation of HMG CoA reductase occurs by dephosphorylation mediated by a specific phosphatase and the biochemical step regulated by PBAN in bombykol biosynthesis is similar to the one catalyzed by HMG-CoA reductase in cholesterol biosynthesis, the present results support the idea that phosphoprotein phosphatase has a significant role to regulate bombykol production in the intracellular transduction of PBAN action in B. mori. PMID:7480881

  15. Simultaneous pharmacokinetic and pharmacodynamic analysis of 5α-reductase inhibitors and androgens by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Upreti, Rita; Naredo, Gregorio; Faqehi, Abdullah M M; Hughes, Katherine A; Stewart, Laurence H; Walker, Brian R; Homer, Natalie Z M; Andrew, Ruth

    2015-01-01

    Benign prostatic hyperplasia and prostate cancer can be treated with the 5α-reductase inhibitors, finasteride and dutasteride, when pharmacodynamic biomarkers are useful in assessing response. A novel method was developed to measure the substrates and products of 5α-reductases (testosterone, 5α-dihydrotestosterone (DHT), androstenedione) and finasteride and dutasteride simultaneously by liquid chromatography tandem mass spectrometry, using an ABSciex QTRAP(®) 5500, with a Waters Acquity™ UPLC. Analytes were extracted from serum (500 µL) via solid-phase extraction (Oasis(®) HLB), with (13)C3-labelled androgens and d9-finasteride included as internal standards. Analytes were separated on a Kinetex C18 column (150 × 3 mm, 2.6 µm), using a gradient run of 19 min. Temporal resolution of analytes from naturally occurring isomers and mass +2 isotopomers was ensured. Protonated molecular ions were detected in atmospheric pressure chemical ionisation mode and source conditions optimised for DHT, the least abundant analyte. Multiple reaction monitoring was performed as follows: testosterone (m/z 289 → 97), DHT (m/z 291 → 255), androstenedione (m/z 287 → 97), dutasteride (m/z 529 → 461), finasteride (m/z 373 → 317). Validation parameters (intra- and inter-assay precision and accuracy, linearity, limits of quantitation) were within acceptable ranges and biological extracts were stable for 28 days. Finally the method was employed in men treated with finasteride or dutasteride; levels of DHT were lowered by both drugs and furthermore the substrate concentrations increased. PMID:25281165

  16. The dark side of 5α-reductase inhibitors' therapy: sexual dysfunction, high Gleason grade prostate cancer and depression.

    Science.gov (United States)

    Traish, Abdulmaged M; Mulgaonkar, Ashwini; Giordano, Nicholas

    2014-06-01

    With aging, abnormal benign growth of the prostate results in benign prostate hyperplasia (BPH) with concomitant lower urinary tract symptoms (LUTS). Because the prostate is an androgen target tissue, and transforms testosterone into 5α-dihydrotestosterone (5α-DHT), a potent androgen, via 5α-reductase (5α-R) activity, inhibiting this key metabolic reaction was identified as a target for drug development to treat symptoms of BPH. Two drugs, namely finasteride and dutasteride were developed as specific 5α-reductase inhibitors (5α-RIs) and were approved by the U.S. Food and Drug Administration for the treatment of BPH symptoms. These agents have proven useful in the reducing urinary retention and minimizing surgical intervention in patients with BPH symptoms and considerable literature exists describing the benefits of these agents. In this review we highlight the adverse side effects of 5α-RIs on sexual function, high grade prostate cancer incidence, central nervous system function and on depression. 5α-Rs isoforms (types 1-3) are widely distributed in many tissues including the central nervous system and inhibition of these enzymes results in blockade of synthesis of several key hormones and neuro-active steroids leading to a host of adverse effects, including loss of or reduced libido, erectile dysfunction, orgasmic dysfunction, increased high Gleason grade prostate cancer, observed heart failure and cardiovascular events in clinical trials, and depression. Considerable evidence exists from preclinical and clinical studies, which point to significant and serious adverse effects of 5α-RIs, finasteride and dutasteride, on sexual health, vascular health, psychological health and the overall quality of life. Physicians need to be aware of such potential adverse effects and communicate such information to their patients prior to commencing 5α-RIs therapy. PMID:24955220

  17. Rhodium-Catalyzed Decarbonylation of Aldoses

    DEFF Research Database (Denmark)

    Monrad, Rune; Madsen, Robert

    2007-01-01

    A catalytic procedure is described for decarbonylation of unprotected aldoses to afford alditols with one less carbon atom. The reaction is performed with the rhodium complex Rh(dppp)2Cl in a refluxing diglyme - DMA solution. A slightly improved catalyst turnover is observed when a catalytic amount...

  18. Adverse effects of 5α-reductase inhibitors: What do we know, don't know, and need to know?

    Science.gov (United States)

    Traish, Abdulmaged M; Melcangi, Roberto Cosimo; Bortolato, Marco; Garcia-Segura, Luis M; Zitzmann, Michael

    2015-09-01

    Steroids are important physiological orchestrators of endocrine as well as peripheral and central nervous system functions. One of the key processes for regulation of these molecules lies in their enzymatic processing by a family of 5α-reductase (5α-Rs) isozymes. By catalyzing a key rate-limiting step in steroidogenesis, this family of enzymes exerts a crucial role not only in the physiological control but also in pathological events. Indeed, both 5α-R inhibition and supplementation of 5α-reduced metabolites are currently used or have been proposed as therapeutic strategies for a wide array of pathological conditions. In particular, the potent 5α-R inhibitors finasteride and dutasteride are used in the treatments of benign prostatic hyperplasia (BPH), as well as in male pattern hair loss (MPHL) known as androgenetic alopecia (AGA). Recent preclinical and clinical findings indicate that 5α-R inhibitors evoke not only beneficial, but also adverse effects. Future studies should investigate the biochemical and physiological mechanisms that underlie the persistence of the adverse sexual side effects to determine why a subset of patients is afflicted with such persistence or irreversible adverse effects. Also a better focus of clinical research is urgently needed to better define those subjects who are likely to be adversely affected by such agents. Furthermore, research on the non-sexual adverse effects such as diabetes, psychosis, depression, and cognitive function are needed to better understand the broad spectrum of the effects these drugs may elicit during their use in treatment of AGA or BPH. In this review, we will summarize the state of art on this topic, overview the key unresolved questions that have emerged on the pharmacological targeting of these enzymes and their products, and highlight the need for further studies to ascertain the severity and duration of the adverse effects of 5α-R inhibitors, as well as their biological underpinnings. PMID

  19. 5-alpha reductase inhibitors and prostate cancer prevention%5α还原酶抑制剂与前列腺癌预防

    Institute of Scientific and Technical Information of China (English)

    万奔

    2012-01-01

    5-alpha reductase inhibitors decrease the level of dihydrotestosterone (DHT) by inhibiting 5-alpha reductase. Trials on 5-alpha reductase inhibitors in prostate cancer prevention showed that they could significantly decrease the incidence of prostate cancer, but meanwhile increase high-grade cases as well. Recent studies demonstrated that 5-alpha reductase inhibitors could reduce not only the prostate volume but also the volume of Gleason grade 3 prostate cancer, which made easier the detection of higher-grade prostate cancer in the second biopsy. 5-alpha reductase inhibitors could also increase the sensitivity of prostate biopsy in detecting prostate cancer, particularly that of a higher grade. The evidence we have obtained leads to the conclusion that 5-alpha reductase inhibitors do not increase the incidence of high-grade prostate cancer, but on the contrary help its earlier detection.%5α还原酶抑制剂通过抑制5α还原酶降低双氢睾酮水平.应用5α还原酶抑制剂进行的前列腺癌预防研究显示,5α还原酶抑制剂可以降低前列腺癌发病率,但同时也出现高级别前列腺癌病例增加的现象,引起广泛关注.有研究和分析显示,5α还原酶抑制剂使前列腺体积缩小,同时也缩小Gleason评分为3分患者的前列腺癌体积,使得再次穿刺更容易发现Gleason评分为4分以上的前列腺癌.另外5α还原酶抑制剂显著提高前列腺穿刺诊断前列腺癌和高级别前列腺癌敏感度.笔者认为5α还原酶抑制剂不但不增加高级别前列腺癌的发生率,反而会帮助我们更早发现高级别前列腺癌.

  20. Discovery of novel hepatoselective HMG-CoA reductase inhibitors for treating hypercholesterolemia: a bench-to-bedside case study on tissue selective drug distribution.

    Science.gov (United States)

    Pfefferkorn, Jeffrey A; Litchfield, John; Hutchings, Richard; Cheng, Xue-Min; Larsen, Scott D; Auerbach, Bruce; Bush, Mark R; Lee, Chitase; Erasga, Noe; Bowles, Daniel M; Boyles, David C; Lu, Gina; Sekerke, Catherine; Askew, Valerie; Hanselman, Jeffrey C; Dillon, Lisa; Lin, Zhiwu; Robertson, Andrew; Olsen, Karl; Boustany, Carine; Atkinson, Karen; Goosen, Theunis C; Sahasrabudhe, Vaishali; Chupka, Jonathan; Duignan, David B; Feng, Bo; Scialis, Renato; Kimoto, Emi; Bi, Yi-An; Lai, Yurong; El-Kattan, Ayman; Bakker-Arkema, Rebecca; Barclay, Paul; Kindt, Erick; Le, Vu; Mandema, Jaap W; Milad, Mark; Tait, Bradley D; Kennedy, Robert; Trivedi, Bharat K; Kowala, Mark

    2011-05-01

    The design of drugs with selective tissue distribution can be an effective strategy for enhancing efficacy and safety, but understanding the translation of preclinical tissue distribution data to the clinic remains an important challenge. As part of a discovery program to identify next generation liver selective HMG-CoA reductase inhibitors we report the identification of (3R,5R)-7-(4-((3-fluorobenzyl)carbamoyl)-5-cyclopropyl-2-(4-fluorophenyl)-1H-imidazol-1-yl)-3,5-dihydroxyheptanoic acid (26) as a candidate for treating hypercholesterlemia. Clinical evaluation of 26 (PF-03491165), as well as the previously reported 2 (PF-03052334), provided an opportunity for a case study comparison of the preclinical and clinical pharmacokinetics as well as pharmacodynamics of tissue targeted HMG-CoA reductase inhibitors. PMID:21183342

  1. Use of 5 alpha-reductase inhibitors for lower urinary tract symptoms and risk of prostate cancer in Swedish men : nationwide, population based case-control study

    OpenAIRE

    Robinson, David; Garmo, Hans; Bill-Axelson, Anna; Mucci, Lorelei; Holmberg, Lars; Stattin, Pär

    2013-01-01

    Objective To assess the association between 5 alpha-reductase inhibitor (5-ARI) use in men with lower urinary tract symptoms and prostate cancer risk. Design Nationwide, population based case-control study for men diagnosed with prostate cancer in 2007-09 within the Prostate Cancer data Base Sweden 2.0. Setting The National Prostate Cancer Register, National Patient Register, census, and Prescribed Drug Register in Sweden, from which we obtained data on 5-ARI use before date of prostate cance...

  2. Impact of preoperative 5α-reductase inhibitors on perioperative blood loss in patients with benign prostatic hyperplasia: a meta-analysis of randomized controlled trials

    OpenAIRE

    Zhu, Yi-Ping; Dai, Bo; Zhang, Hai-Liang; Shi, Guo-Hai; Ye, Ding-wei

    2015-01-01

    Background The ability of 5α-reductase inhibitors (5ARIs) to decrease blood loss during transurethral resection of the prostate (TURP) for benign prostatic hyperplasia (BPH) remains controversial. We aimed to conduct a meta-analysis of all randomized controlled trials (RCTs) to establish the role of 5ARI use prior to TURP. Methods We searched studies from the electronic databases PubMed, Embase, Scopus, and Cochrane Library from inception to March 25, 2014. Meta-analysis was performed using t...

  3. Peripheral zone prostate-specific antigen density: an effective parameter for prostate cancer prediction in men receiving 5α-reductase inhibitors

    OpenAIRE

    Koo, Kyo Chul; Lee, Dong Hoon; Lee, Seung Hwan; Chung, Byung Ha

    2013-01-01

    Purpose: To evaluate the predictive performance of various parameters derived from volume-adjusted prostate-specific antigen (PSA) values in detecting prostate cancer (PCa) and high-grade (Gleason score≥7) PCa according to treatment with a 5α-reductase inhibitor (5ARI). Methods: The results of 3,520 prostate biopsies performed between May 2006 and January 2013 were retrospectively assessed. With adjustment for age, 291 patients who had received 5ARI treatment for more than 6 months were ident...

  4. Combination of 5α-reductase inhibitor with combined androgen blockade (CAB) as a novel cytoreductive regimen before prostate brachytherapy: Ultra-CAB

    OpenAIRE

    Muro, Yusuke; Kosaka, Takeo; Mizuno, Ryuichi; Ohashi, Toshio; Shigematsu, Naoyuki; Oya, Mototsugu

    2015-01-01

    We report a first case of using a 5α-reductase inhibitor (5ARI) and combined androgen blockade (CAB) as a cytoreductive regimen before prostate brachytherapy. Prostate volume reduction with CAB is limited to approximately 40% in most cases, making it difficult to meet anatomical constraints to perform these procedures in cases with large prostate volume. With the added administration of 5ARI, further volume reduction can be expected. Here, we describe this cytoreductive regimen used in a 63 y...

  5. Use of 5α-reductase inhibitors for lower urinary tract symptoms and risk of prostate cancer in Swedish men: nationwide, population based case-control study

    OpenAIRE

    Robinson, David; Garmo, Hans; Bill-Axelson, Anna; Mucci, Lorelei; Holmberg, Lars; Stattin, Pär

    2013-01-01

    Objective: To assess the association between 5α-reductase inhibitor (5-ARI) use in men with lower urinary tract symptoms and prostate cancer risk. Design: Nationwide, population based case-control study for men diagnosed with prostate cancer in 2007-09 within the Prostate Cancer data Base Sweden 2.0. Setting: The National Prostate Cancer Register, National Patient Register, census, and Prescribed Drug Register in Sweden, from which we obtained data on 5-ARI use before date of prostate cancer ...

  6. Potent increased risk of the initiation of DNA replication in human prostate cancer with the use of 5α-reductase inhibitors

    OpenAIRE

    Kosaka, Takeo; Yasumizu, Yota; Miyazaki, Yasumasa; Miyajima, Akira; Kikuchi, Eiji; Oya, Mototsugu

    2014-01-01

    Recent clinical studies have raised the clinically important question of the relationship between dihydrotestosterone (DHT) and prostate cancer (PCa) progression. The significance of DHT or 5α-reductase inhibitors (5ARI) in PCa development and progression has not yet been fully characterized. The aim of this study was to determine whether the initiation of DNA replication was influenced by DHT in PCa. Three cell lines were used. LNCaP: a human PCa cell line that exhibits androgen-dependent pr...

  7. [REVIEW OF CLINICAL STUDIES ON COMBINATION THERAPY OF 5α-REDUCTASE INHIBITORS AND α1-BLOCKERS IN PATIENTS WITH BENIGN PROSTATIC HYPERPLASIA].

    Science.gov (United States)

    Spivak, L G; Lokshin, K L; Vinarov, A Z

    2015-01-01

    The review presents the results of studies on combination therapy of 5α-reductase inhibitors and α-blockers in patients with benign prostatic hyperplasia (BPH). These data demonstrate a significant advantage of the combination therapy versus monotherapy in terms of quality of life and subjective symptoms as well as the safety, better results in the prevention of BPH progression and acute urinary retention, and reduced need for surgery. PMID:26665780

  8. A systematic review of the effects and mechanisms of preoperative 5α-reductase inhibitors on intraoperative haemorrhage during surgery for benign prostatic hyperplasia

    OpenAIRE

    Zong, Huan-Tao; Peng, Xiao-Xia; Yang, Chen-Chen; Yong ZHANG

    2011-01-01

    5α-reductase inhibitors (5α-RIs), including finasteride and dutasteride, are commonly used medical therapies for benign prostatic hyperplasia (BPH). Many studies reported that preoperative 5α-RI had impact on intraoperative haemorrhage during surgery for BPH, but it was still in controversial. So, we conducted a systematic review of the effects and mechanisms of 5α-RIs on intraoperative bleeding for BPH. MEDLINE, EMBASE, the Cochrane Controlled Trail Register of Controlled Trials and the refe...

  9. Use of 5-alpha-reductase inhibitors did not increase the risk of cardiovascular diseases in patients with benign prostate hyperplasia: a five-year follow-up study.

    Directory of Open Access Journals (Sweden)

    Teng-Fu Hsieh

    Full Text Available This nationwide population-based study investigated the risk of cardiovascular diseases after 5-alpha-reductase inhibitor therapy for benign prostate hyperplasia (BPH using the National Health Insurance Research Database (NHIRD in Taiwan.In total, 1,486 adult patients newly diagnosed with BPH and who used 5-alpha-reductase inhibitors were recruited as the study cohort, along with 9,995 subjects who did not use 5-alpha-reductase inhibitors as a comparison cohort from 2003 to 2008. Each patient was monitored for 5 years, and those who subsequently had cardiovascular diseases were identified. A Cox proportional hazards model was used to compare the risk of cardiovascular diseases between the study and comparison cohorts after adjusting for possible confounding risk factors.The patients who received 5-alpha-reductase inhibitor therapy had a lower cumulative rate of cardiovascular diseases than those who did not receive 5-alpha-reductase inhibitor therapy during the 5-year follow-up period (8.4% vs. 11.2%, P=0.003. In subgroup analysis, the 5-year cardiovascular event hazard ratio (HR was lower among the patients older than 65 years with 91 to 365 cumulative defined daily dose (cDDD 5-alpha-reductase inhibitor use (HR=0.63, 95% confidence interval (CI 0.42 to 0.92; P=0.018, however there was no difference among the patients with 28 to 90 and more than 365 cDDD 5-alpha-reductase inhibitor use (HR=1.14, 95% CI 0.77 to 1.68; P=0.518 and HR=0.83, 95% CI 0.57 to 1.20; P=0.310, respectively.5-alpha-reductase inhibitor therapy did not increase the risk of cardiovascular events in the BPH patients in 5 years of follow-up. Further mechanistic research is needed.

  10. Growth of LAPC4 prostate cancer xenograft tumor is insensitive to 5α-reductase inhibitor dutasteride.

    Science.gov (United States)

    Garcia, Raquel Ramos; Masoodi, Khalid Z; Pascal, Laura E; Nelson, Joel B; Wang, Zhou

    2014-01-01

    Intermittent androgen deprivation therapy (IADT) allows prostate cancer patients a break from the side-effects of continuous androgen deprivation therapy (ADT). Although clinical studies suggest that IADT can significantly improve patient quality of life over ADT, it has not been demonstrated to improve patient survival. Recently, increased survival has been demonstrated when 5α-reductase inhibitors have been used during the off-cycle of IADT in animal xenograft tumor models LNCaP and LuCaP35. In the current study, the sensitivity of LAPC4 xenograft tumor regrowth to the 5ARI dutasteride was determined. Tumor regrowth and gene expression changes in LAPC4 tumors were compared to the previously determined response of LNCaP and LuCaP35 xenograft tumors to 5ARI treatment during the off-cycle of IADT, LAPC4, LNCaP and LuCaP35 tumors were sensitive to androgen manipulation. However, in contrast to LNCaP and LuCaP35, dutasteride treatment during testosterone-stimulated prostate regrowth did not affect tumor regrowth or the expression of androgen responsive genes. Tumor response to dutasteride during the off-cycle of IADT is variable in xenograft prostate tumor models. Future studies will be required to elucidate the mechanisms contributing to the dutasteride resistance observed in the LAPC4 model during the off-cycle. PMID:25374909

  11. 5-Alpha reductase inhibitors in men with an enlarged prostate: an evaluation of outcomes and therapeutic alternatives.

    Science.gov (United States)

    Naslund, Michael; Regan, Timothy S; Ong, Christine; Hogue, Susan L

    2008-05-01

    This article presents background information and highlights key findings from a managed care perspective related to enlarged prostate (EP) in Medicare-eligible patients. This article does not provide a comprehensive review of EP but instead attempts to increase the current understanding of EP through discussion of its prevalence in men aged > or =65 years, its associated economic burden, and some available treatment options. This supplement includes 3 additional articles, all of which present data from a naturalistic, managed care setting. The article by Fenter et al assesses differences in outcomes between elderly EP patients treated with finasteride and those treated with dutasteride in relation to the risks of acute urinary retention and prostate-related surgery. Issa et al conduct a comparative analysis of the combined use of alpha-blockers and 5-alpha reductase inhibitors to treat EP. The final article compares medical costs incurred within the first year of initiating treatment for EP patients receiving finasteride versus dutasteride. This supplement is intended to assist managed care formulary decision makers in evaluating key clinical and economic data that differentiate dutasteride and finasteride within the Medicare-aged population. Although the information presented is not designed to illustrate the superiority of one product over the other, it answers important questions in relation to treating EP in elderly men and raises substantial issues beyond medication costs. PMID:18611088

  12. Enzyme-linked immunosorbent assays for doping control of 5alpha-reductase inhibitors finasteride and dutasteride.

    Science.gov (United States)

    Brun, Eva M; Torres, Ana; Ventura, Rosa; Puchades, Rosa; Maquieira, Angel

    2010-06-25

    Finasteride and dutasteride are 5alpha-reductase inhibitors included in the World Anti-Doping Agency's list of banned substances. Two highly sensitive and selective ELISA assays were developed for these compounds. Polyclonal rabbit antibodies were raised using synthesized haptens and other commercial products. The best immunoassay obtained, based on an antibody-coated format, showed a limit of detection of 0.01 microg L(-1) and an IC(50) of 0.75 microg L(-1) for finasteride (cross-reactivity with dutasteridefinasteride and dutasteride determination, with limits of detection of 0.013 and 0.021 microg L(-1), and IC(50) values 0.18 and 1.18 microg L(-1), respectively. Both assays were highly selective to a set of anabolic steroids, but they showed 37% and 30% cross-reactivity with the major urinary metabolite of finasteride, allowing its determination. The developed ELISA had better sensitivity than HPLC/MS/MS method and was applied as a screening technique to quantify dutasteride, finasteride, and its main metabolite in human urine without sample pre-treatment. Moreover, the analysis of dutasteride's excretion urines by ELISA was used to obtain its human excretion rate, essential to improve the analytical strategies about this type of drugs (permitted as medicines and prohibited in sport) and to establish an effective anti-doping policy. PMID:20541645

  13. Five-alpha Reductase Inhibitor Influences Expression of Androgen Receptor and HOXB13 in Human Hyperplastic Prostate Tissue

    Directory of Open Access Journals (Sweden)

    Chaeyong Jung

    2013-12-01

    Full Text Available Objectives Five-alpha reductase inhibitors (5ARIs are known as chemopreventive agents in prostate cancer with a risk of high-grade disease. This study evaluated the effects of 5ARI on androgen receptor (AR and proteins involved in prostate cell growth such as HOXB13 expression in human prostate tissue and LNCaP prostate cancer cells. Materials and Methods We retrospectively selected 21 patients who underwent TURP between March 2007 and February 2010 for previously confirmed BPH by prostate biopsy. They were grouped into control (group 1, n = 9 and 5ARI treatment (group 2, n = 12 before TURP. AR and HOXB13 expression in prostate tissue was evaluated by immunohistochemical staining. We tested the effect of 5ARI on the expression of AR, prostate specific antigen (PSA and HOXB13 in LNCaP cells. Cells were assessed by Western blot analysis, MTT in vitro proliferation assay, and ELISA. Results: Group 2 showed stronger reactivity for AR and HOXB13 than those of the group 1. MTT assay showed death of LNCaP cells at 25uM of 5ARI. At the same time, ELISA assay for PSA showed that 5ARI inhibited secretion of PSA in LNCaP cells. Western blot analysis showed that 5ARI did not greatly alter AR expression but it stimulated the expression of HOXB13. Conclusions These results demonstrated that 5ARI influences AR and HOXB13 expression in both LNCaP cells and human prostate tissue. In order to use 5ARI in chemoprevention of prostate cancer, we still need to clarify the influence of 5ARI in ARs and oncogenic proteins and its regulation pathway.

  14. Structural comparison of chromosomal and exogenous dihydrofolate reductase from Staphylococcus aureus in complex with the potent inhibitor trimethoprim

    Energy Technology Data Exchange (ETDEWEB)

    Heaslet, Holly; Harris, Melissa; Fahnoe, Kelly; Sarver, Ronald; Putz, Henry; Chang, Jeanne; Subramanyam, Chakrapani; Barreiro, Gabriela; Miller, J. Richard; Pfizer

    2010-09-02

    Dihydrofolate reductase (DHFR) is the enzyme responsible for the NADPH-dependent reduction of 5,6-dihydrofolate to 5,6,7,8-tetrahydrofolate, an essential cofactor in the synthesis of purines, thymidylate, methionine, and other key metabolites. Because of its importance in multiple cellular functions, DHFR has been the subject of much research targeting the enzyme with anticancer, antibacterial, and antimicrobial agents. Clinically used compounds targeting DHFR include methotrexate for the treatment of cancer and diaminopyrimidines (DAPs) such as trimethoprim (TMP) for the treatment of bacterial infections. DAP inhibitors of DHFR have been used clinically for >30 years and resistance to these agents has become widespread. Methicillin-resistant Staphylococcus aureus (MRSA), the causative agent of many serious nosocomial and community acquired infections, and other gram-positive organisms can show resistance to DAPs through mutation of the chromosomal gene or acquisition of an alternative DHFR termed 'S1 DHFR.' To develop new therapies for health threats such as MRSA, it is important to understand the molecular basis of DAP resistance. Here, we report the crystal structure of the wild-type chromosomal DHFR from S. aureus in complex with NADPH and TMP. We have also solved the structure of the exogenous, TMP resistant S1 DHFR, apo and in complex with TMP. The structural and thermodynamic data point to important molecular differences between the two enzymes that lead to dramatically reduced affinity of DAPs to S1 DHFR. These differences in enzyme binding affinity translate into reduced antibacterial activity against strains of S. aureus that express S1 DHFR.

  15. Crystal structure of enoyl-acyl carrier protein reductase (FabK) from Streptococcus pneumoniae reveals the binding mode of an inhibitor.

    Science.gov (United States)

    Saito, Jun; Yamada, Mototsugu; Watanabe, Takashi; Iida, Maiko; Kitagawa, Hideo; Takahata, Sho; Ozawa, Tomohiro; Takeuchi, Yasuo; Ohsawa, Fukuichi

    2008-04-01

    Enoyl-acyl carrier protein (ACP) reductases are critical for bacterial type II fatty acid biosynthesis and thus are attractive targets for developing novel antibiotics. We determined the crystal structure of enoyl-ACP reductase (FabK) from Streptococcus pneumoniae at 1.7 A resolution. There was one dimer per asymmetric unit. Each subunit formed a triose phosphate isomerase (TIM) barrel structure, and flavin mononucleotide (FMN) was bound as a cofactor in the active site. The overall structure was similar to the enoyl-ACP reductase (ER) of fungal fatty acid synthase and to 2-nitropropane dioxygenase (2-ND) from Pseudomonas aeruginosa, although there were some differences among these structures. We determined the crystal structure of FabK in complex with a phenylimidazole derivative inhibitor to envision the binding site interactions. The crystal structure reveals that the inhibitor binds to a hydrophobic pocket in the active site of FabK, and this is accompanied by induced-fit movements of two loop regions. The thiazole ring and part of the ureido moiety of the inhibitor are involved in a face-to-face pi-pi stacking interaction with the isoalloxazine ring of FMN. The side-chain conformation of the proposed catalytic residue, His144, changes upon complex formation. Lineweaver-Burk plots indicate that the inhibitor binds competitively with respect to NADH, and uncompetitively with respect to crotonoyl coenzyme A. We propose that the primary basis of the inhibitory activity is competition with NADH for binding to FabK, which is the first step of the two-step ping-pong catalytic mechanism. PMID:18305197

  16. Medicinal flowers. XXXX . Structures of dihydroisocoumarin glycosides and inhibitory effects on aldose reducatase from the flowers of Hydrangea macrophylla var.thunbergii.

    Science.gov (United States)

    Liu, Jiang; Nakamura, Seikou; Zhuang, Yan; Yoshikawa, Masayuki; Hussein, Ghazi Mohamed Eisa; Matsuo, Kyohei; Matsuda, Hisashi

    2013-01-01

    Six dihydroisocoumarin glycosides, florahydrosides I and II, thunberginol G 8-O-β-d-glucopyranoside, thunberginol C 8-O-β-d-glucopyranoside, 4-hydroxythunberginol G 3'-O-β-d-glucopyranoside, and thunberginol D 3'-O-β-d-glucopyranoside, have been isolated from the flowers of Hydrangea macrophylla Seringe var. thunbergii Makino (Saxifragaceae) together with 20 known compounds. The chemical structures of the new compounds were elucidated on the basis of chemical and physicochemical evidence. Among the constituents, acylated quinic acid analog, neochlorogenic acid, was shown to substantially inhibit aldose reductase [IC50=5.6 µm]. In addition, the inhibitory effects on aldose reductase of several caffeoylquinic acid analogs were examined for structure-activity relationship study. As the results, 4,5-O-trans-p-dicaffeoyl-d-quinic acid was found to exhibit a potent inhibitory effect [IC50=0.29 µm]. PMID:23727779

  17. α-Blocker Monotherapy and α-Blocker Plus 5-Alpha-Reductase Inhibitor Combination Treatment in Benign Prostatic Hyperplasia; 10 Years' Long-Term Results

    OpenAIRE

    Shin, Teak Jun; Kim, Chun Il; Park, Choal Hee; Kim, Byung Hoon; Kwon, Young Kee

    2012-01-01

    Purpose We compared the effects of alpha-adrenergic receptor blocker (α-blocker) monotherapy with those of combination therapy with α-blocker and 5-alpha-reductase inhibitor (5-ARI) on benign prostatic hyperplasia (BPH) progression for over 10 years. Materials and Methods A total of 620 patients with BPH who received α-blocker monotherapy (α-blocker group, n=368) or combination therapy (combination group, n=252) as their initial treatment were enrolled from January 1989 to June 2000. The inci...

  18. Combination of 5α-reductase inhibitor with combined androgen blockade (CAB) as a novel cytoreductive regimen before prostate brachytherapy: Ultra-CAB.

    Science.gov (United States)

    Muro, Yusuke; Kosaka, Takeo; Mizuno, Ryuichi; Ohashi, Toshio; Shigematsu, Naoyuki; Oya, Mototsugu

    2015-01-01

    We report a first case of using a 5α-reductase inhibitor (5ARI) and combined androgen blockade (CAB) as a cytoreductive regimen before prostate brachytherapy. Prostate volume reduction with CAB is limited to approximately 40% in most cases, making it difficult to meet anatomical constraints to perform these procedures in cases with large prostate volume. With the added administration of 5ARI, further volume reduction can be expected. Here, we describe this cytoreductive regimen used in a 63 year-old prostate cancer patient who became eligible to receive brachytherapy after dutasteride (0.5 mg daily) was added to CAB and prostate volume reduction of 57% was achieved. PMID:26069888

  19. Design and Synthesis of Chalcone Derivatives as Inhibitors of the Ferredoxin — Ferredoxin-NADP+ Reductase Interaction of Plasmodium falciparum: Pursuing New Antimalarial Agents

    OpenAIRE

    Hery Suwito; Jumina; Mustofa; Pratiwi Pudjiastuti; Much Zaenal Fanani; Yoko Kimata-Ariga; Ritsuko Katahira; Toru Kawakami; Toshimichi Fujiwara; Toshiharu Hase; Hasnah Mohd Sirat; Ni Nyoman Tri Puspaningsih

    2014-01-01

    Some chalcones have been designed and synthesized using Claisen-Schmidt reactions as inhibitors of the ferredoxin and ferredoxin-NADP+ reductase interaction to pursue a new selective antimalaria agent. The synthesized compounds exhibited inhibition interactions between PfFd-PfFNR in the range of 10.94%–50%. The three strongest inhibition activities were shown by (E)-1-(4-aminophenyl)-3-(4-methoxyphenyl)prop-2-en-1-one (50%), (E)-1-(4-aminophenyl)-3-(2,4-dimethoxyphenyl)prop-2-en-1-one (38.16%...

  20. The ribonucleoside diphosphate reductase inhibitor (E)-2'-Deoxy-(fluoromethylene) cytidine, acts as a cytotoxic radiosensitizer on human cancer cell lines in vitro.

    OpenAIRE

    Coucke, Philippe; Decosterd, L-A; Li, Y-X; Cottin, E.; Chen, X; Sun, L-Q; Stern, S.; Paschoud, N; Denekamp, J.

    1999-01-01

    ABSTRACT (E)-2*-Deoxy-(fluoromethylene)cytidine (FMdC) is known as an inhibitor of ribonucleoside diphosphate reductase, a key enzyme in the de novo pathway of DNA synthesis. FMdC was tested as a modifier of radiation response in vitro on a human colon carcinoma cell line (WiDr), and the observed radiosensitization was confirmed on two human cervix cancer cell lines (C33-A and SiHa). Using the clonogenic assay, the effect ratio (ER) at a clinically relevant dose level of ...

  1. In Silico Screening, Synthesis and In Vitro Evaluation of Some Quinazolinone and Pyridine Derivatives as Dihydrofolate Reductase Inhibitors for Anticancer Activity

    OpenAIRE

    Nerkar, A. G.; Saxena, A. K.; S. A. Ghone; A. K. Thaker

    2009-01-01

    Dihydrofolate reductase (DHFR) is the important target for anticancer drugs belonging to the class of antimetabolites as the enzyme plays important role in the de novo purine synthesis. We here report the in silico screening to obtain best fit molecules as DHFR inhibitors, synthesis of some ʻbest fitʼ quinazolinone from 2-phenyl-3-(substituted-benzilidine-amino) quinazolinones (Quinazolinone Shiff's bases) QSB1-5 and pyridine-4-carbohydrazide Shiff's bases (ISB1-5) derivatives and their in vi...

  2. 1H and 13C NMR Chemical Shift Assignments and Conformational Analysis for the Two Diastereomers of the Vitamin K Epoxide Reductase Inhibitor Brodifacoum

    International Nuclear Information System (INIS)

    Proton and 13C NMR chemical shift assignments and 1H-1H scalar couplings for the two diastereomers of the vitamin K epoxide reductase (VKOR) inhibitor brodifacoum have been determined from acetone solutions containing both diastereomers. Data were obtained from homo- and heteronuclear correlation spectra acquired at 1H frequencies of 750 and 900 MHz over a 268-303 K temperature range. Conformations inferred from scalar coupling and 1-D NOE measurements exhibit large differences between the diastereomers. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

  3. The role of 5-alpha reductase inhibitors in prostate pathophysiology: Is there an additional advantage to inhibition of type 1 isoenzyme?

    Science.gov (United States)

    Goldenberg, Larry; So, Alan; Fleshner, Neil; Rendon, Ricardo; Drachenberg, Darrel; Elhilali, Mostafa

    2009-06-01

    Normal growth and function of the prostate are contingent on the reduction of testosterone to dihydrotestosterone (DHT) by 5-alpha reductase (5-AR) enzymes types 1 and 2. It has been theorized that an overabundance of DHT may be implicated in the pathogenesis of both benign prostatic hyperplasia (BPH) and prostate cancer. Inhibitors of 5-AR such as dutasteride and finasteride may therefore have an important role in the prevention and treatment of BPH and prostate cancer. Dutasteride provides greater suppression of DHT than finasteride, thereby underlying the hypothesis that inhibition of both type 1 and type 2 would provide correspondingly greater protection than inhibition of type 2 alone. We review the potential significance of the 5-AR inhibitors in reducing the risk of prostate cancer according to the basic biology of prostate disease. PMID:19543428

  4. Selective induction of apoptosis in the hamster flank sebaceous gland organ by a topical liposome 5-alpha-reductase inhibitor: a treatment strategy for acne.

    Science.gov (United States)

    Li, Lingna; Tang, Li; Baranov, Eugene; Yang, Meng; Amoh, Yasuyuki; Katsuoka, Kensei; Hoffman, Robert M

    2010-02-01

    Acne is a very widespread cosmesis problem. Isotretinoin, a synthetic oral retinoid is used to treat acne, which is androgen dependent. Numerous side-effects occur from this treatment. 5-alpha-Reductase plays a critical role in normal and pathological androgen-dependent processes. We have taken the approach to develop a selective, effective, topically-applied 5-alpha-reductase inhibitor to modify unwanted or pathological processes in the pilosebaceous unit such as acne. Toward this goal, we have previously developed a selective liposome hair follicle targeting system. We demonstrate in this report that the 5-alpha-reductase inhibitor N,N-diethyl-4-methyl-3-oxo-4-aza-5alpha-androstane-17beta-carboxamide (4-MA) incorporated into liposomes induces apoptosis and inhibits growth of the dihydrotestosterone (DHT)-dependent hamster flank organ sebaceous gland. We have compared topical application of liposome 4-MA and solvent-formulated 4-MA and observed selective efficacy of topical application of liposome 4-MA by the reduction of size and induction of apoptosis only in the treated hamster flank organ. Apoptosis induced by liposome 4-MA in the treated flank organ sebaceous gland cells was observed both by assays for DNA fragments (transferase deoxytidyl uridine end labeling) and by observation of condensed and fragmented nuclei. When 4-MA was topically applied formulated in ethanol and glycerol without liposomes, the selective efficacy was lost. Liposome 4-MA did not significantly affect prostate weight, testosterone/DHT ratios or bodyweight gain compared to controls indicating safety as well as efficacy of topical application of liposome 4-MA for pathological processes such as acne. PMID:20175850

  5. Carotid intimal-media thickness as a surrogate for cardiovascular disease events in trials of HMG-CoA reductase inhibitors

    Directory of Open Access Journals (Sweden)

    Morgan Timothy

    2005-03-01

    Full Text Available Abstract Background Surrogate measures for cardiovascular disease events have the potential to increase greatly the efficiency of clinical trials. A leading candidate for such a surrogate is the progression of intima-media thickness (IMT of the carotid artery; much experience has been gained with this endpoint in trials of HMG-CoA reductase inhibitors (statins. Methods and Results We examine two separate systems of criteria that have been proposed to define surrogate endpoints, based on clinical and statistical arguments. We use published results and a formal meta-analysis to evaluate whether progression of carotid IMT meets these criteria for HMG-CoA reductase inhibitors (statins. IMT meets clinical-based criteria to serve as a surrogate endpoint for cardiovascular events in statin trials, based on relative efficiency, linkage to endpoints, and congruency of effects. Results from a meta-analysis and post-trial follow-up from a single published study suggest that IMT meets established statistical criteria by accounting for intervention effects in regression models. Conclusion Carotid IMT progression meets accepted definitions of a surrogate for cardiovascular disease endpoints in statin trials. This does not, however, establish that it may serve universally as a surrogate marker in trials of other agents.

  6. Symptomatic benign prostatic hyperplasia: the role of 5-alpha-reductase inhibitors in the prevention of acute urinary retention and surgical therapy

    Directory of Open Access Journals (Sweden)

    Norma Marigliano

    2012-01-01

    Full Text Available Benign prostatic hyperplasia (BPH is a disease that affects over 50% of males aged 50 years or older. In men aged >80 years, the incidence is 90%. BPH occurs in 9-25% of males aged 40 to 79 years. Fifty percent of patients with BPH are symptomatic. The symptoms include reduced urinary flow, nocturia, defective bladder emptying, urinary hesitancy, and dysuria. Disease progression can be associated with acute urinary retention (AUR. Prostatic obstruction includes mechanical and dynamic components, the latter mediated by alpha-muscarinic receptors. Treatment with alpha-1-blockers (alfuzosin, doxazosin, tamsulosin, and terazosin leads to rapid amelioration of symptoms and urinary flow, usually within one or two weeks. The 5-alpha reductase inhibitors (5-ARIs are “disease-modifying drugs.” They control the growth of the prostate by blocking the conversion of testosterone into dihydrotestosterone (DHT. Finasteride is a 5–ARI that is selective for type 2 receptors. Dutasteride is a powerful inhibitor of both 5- alpha reductase isoforms (type 1 and 2 and produces more complete suppression of DHT synthesis than finasteride. Dutasteride also has a much longer half-life than finasteride (five weeks versus five to six hours. The authors review the results of clinical trials involving finasteride and dutasteride, with and without alpha-1-blockers, highlighting the important role of dutasteride in improving acute urinary retention and eliminating the need for surgical therapy.

  7. Pitavastatin – a new inhibitor of the HMG-CoA reductase: peculiarities of clinical pharmacology and perspectives of its usage in treatment of cardiovascular diseases

    Directory of Open Access Journals (Sweden)

    Dzyak G.V.

    2013-12-01

    Full Text Available Cardiovascular mortality makes up 66.3 % of the total mortality in Ukraine. Myocardial infarction, stroke, atherosclerosis of peripheral arteries are the diseases caused by atherosclerosis and are prevalent in the mortality structure. One of the most effective means of successful prevention of cardiovascular disease are drugs that reduce the content of atherogenic lipids in the blood. Statins are the first line drugs for the treatment of patients with dyslipidemia and atherosclerosis in accordance with national and international guidelines. The article presents the features of the pharmacokinetics and pharmacodynamics, results of clinical trials and data on the efficacy and safety of a new inhibitor of the HMG-CoA reductase – pitavastatin (Livazo © (Recordati, Italy. Data from several multicenter randomized studies indicate that pitavastatin significantly reduces the level of cholesterol low-density lipoproteins and triglycerides, significantly increases the level of cholesterol high-density lipoproteins after 12 weeks of observation, and contributes to a significant regression of atherosclerotic plaques. It was shown that pitavastatin has a high level of safety and is well tolerated regardless of patients' age and racial origin. Pitavastatin is a new effective inhibitor of HMG -CoA reductase, which has been successfully used in many countries for the dyslipidemia treatment in patients with cardiovascular disease, diabetes, kidney diseases and other comorbid conditions.

  8. Crystallization of mitochondrial rhodoquinol-fumarate reductase from the parasitic nematode Ascaris suum with the specific inhibitor flutolanil

    International Nuclear Information System (INIS)

    Rhodoquinol-fumarate reductase is a key enzyme in the anaerobic respiratory chain of adult A. suum mitochondria. Its crystallization in the presence of a mixture of octaethyleneglycol monododecyl ether and n-dodecyl-β-d-maltopyranoside in a form suitable for X-ray structure analysis is reported. In adult Ascaris suum (roundworm) mitochondrial membrane-bound complex II acts as a rhodoquinol-fumarate reductase, which is the reverse reaction to that of mammalian complex II (succinate-ubiquinone reductase). The adult A. suum rhodoquinol-fumarate reductase was crystallized in the presence of octaethyleneglycol monododecyl ether and n-dodecyl-β-d-maltopyranoside in a 3:2 weight ratio. The crystals belonged to the orthorhombic space group P212121, with unit-cell parameters a = 123.75, b = 129.08, c = 221.12 Å, and diffracted to 2.8 Å resolution using synchrotron radiation. The presence of two molecules in the asymmetric unit (120 kDa × 2) gives a crystal volume per protein mass (VM) of 3.6 Å3 Da−1

  9. Structure-based approach to pharmacophore identification, in silico screening, and three-dimensional quantitative structure-activity relationship studies for inhibitors of Trypanosoma cruzi dihydrofolate reductase function

    Energy Technology Data Exchange (ETDEWEB)

    Schormann, N.; Senkovich, O.; Walker, K.; Wright, D.L.; Anderson, A.C.; Rosowsky, A.; Ananthan, S.; Shinkre, B.; Velu, S.; Chattopadhyay, D. (UAB); (Connecticut); (Southern Research); (DFCI)

    2009-07-10

    We have employed a structure-based three-dimensional quantitative structure-activity relationship (3D-QSAR) approach to predict the biochemical activity for inhibitors of T. cruzi dihydrofolate reductase-thymidylate synthase (DHFR-TS). Crystal structures of complexes of the enzyme with eight different inhibitors of the DHFR activity together with the structure in the substrate-free state (DHFR domain) were used to validate and refine docking poses of ligands that constitute likely active conformations. Structural information from these complexes formed the basis for the structure-based alignment used as input for the QSAR study. Contrary to indirect ligand-based approaches the strategy described here employs a direct receptor-based approach. The goal is to generate a library of selective lead inhibitors for further development as antiparasitic agents. 3D-QSAR models were obtained for T. cruzi DHFR-TS (30 inhibitors in learning set) and human DHFR (36 inhibitors in learning set) that show a very good agreement between experimental and predicted enzyme inhibition data. For crossvalidation of the QSAR model(s), we have used the 10% leave-one-out method. The derived 3D-QSAR models were tested against a few selected compounds (a small test set of six inhibitors for each enzyme) with known activity, which were not part of the learning set, and the quality of prediction of the initial 3D-QSAR models demonstrated that such studies are feasible. Further refinement of the models through integration of additional activity data and optimization of reliable docking poses is expected to lead to an improved predictive ability.

  10. Characterization of a Novel Dithiocarbamate Glutathione Reductase Inhibitor and Its Use as a Tool to Modulate Intracellular Glutathione*

    OpenAIRE

    Seefeldt, Teresa; Zhao, Yong; Chen, Wei; Raza, Ashraf S.; Carlson, Laura; Herman, Jocqueline; Stoebner, Adam; Hanson, Sarah; Foll, Ryan; Guan, Xiangming

    2009-01-01

    Thiol redox state (TRS) is an important parameter to reflect intracellular oxidative stress and is associated with various normal and abnormal biochemical processes. Agents that can be used to increase intracellular TRS will be valuable tools in TRS-related research. Glutathione reductase (GR) is a critical enzyme in the homeostasis of TRS. The enzyme catalyzes the reduction of GSSG to GSH to maintain a high GSH:GSSG ratio. Inhibition of the enzyme can be used to incre...

  11. DNA cleavage, antimicrobial studies and a DFT-based QSAR study of new antimony(III) complexes as glutathione reductase inhibitor.

    Science.gov (United States)

    Tunç, Turgay; Koç, Yasemin; Açık, Leyla; Karacan, Mehmet Sayım; Karacan, Nurcan

    2015-02-01

    New antimony(III) complexes, [Sb(2-aminopyridine)2Cl3] (1a), [Sb(2-aminopyridine)2Br3] (1b), [Sb(5-methyl-2-aminopyridine)2Cl3] (2a), [Sb(5-methyl-2-aminopyridine)2Br3] (2b), [Sb(2-aminopyrimidine)2Cl3] (3a), [Sb(2-aminopyrimidine)2Br3] (3b), [Sb(4,6-dimethoxy-2-aminopyrimidine)2Cl3] (4a), [Sb(4,6-dimethoxy-2-aminopyrimidine)2Br3] (4b), [Sb(2-amino-1,3,5-triazine)2Cl3] (5a), [Sb(2-amino-1,3,5-triazine)2Br3] (5b), [Sb(2-guanidinobenzimidazole) Cl3] (6a), [Sb(2-guanidinobenzimidazole)Br3] (6b) [Sb(2- benzyl-2-thiopseudeourea)2Cl3] (7a) and [Sb(2- benzyl-2-thiopseudeourea)2Br3] (7b) were synthesized. Their structures were characterized by elemental analysis, molecular conductivity, FT-IR, (1)H NMR, LC-MS techniques. Glutathione reductase inhibitor activity, antimicrobial activity and DNA cleavage studies of the complexes were determined. The geometrical structures of the complexes were optimized by DFT/B3LYP method with LANL2DZ as basis set. Calculation results indicated that the equilibrium geometries of all complexes have square pyramidal shape. About 350 molecular descriptors (constitutional, topological, geometrical, electrostatic and quantum chemical parameters) of the complexes were calculated by DFT/B3LYP/LANL2DZ method with CODESSA software. Calculated molecular parameters were correlated to glutathione reductase inhibitory activity values (pIC50) of all complexes by Best Multi-Linear Regression (BMLR) method. Obtained two-parameter QSAR equation shows that increase in "maximum partial charge for a H atom" and decrease in HOMO-LUMO gap would be favorable for the glutathione reductase inhibitory activity. PMID:25459701

  12. In vivo examination of hydroxyurea and the novel ribonucleotide reductase inhibitors trimidox and didox in combination with the reverse transcriptase inhibitor abacavir: suppression of retrovirus-induced immunodeficiency disease.

    Science.gov (United States)

    Sumpter, L Ryan; Inayat, Mohammed S; Yost, Erin E; Duvall, William; Hagan, Espen; Mayhew, Christopher N; Elford, Howard L; Gallicchio, Vincent S

    2004-06-01

    Inhibition of ribonucleotide reductase (RR) has gained attention as a potential strategy for HIV-1 therapy through the success of hydroxyurea (HU) to potentiate the activity of the nucleoside reverse transcriptase inhibitor (NRTI) didanosine (ddI) in clinical trials. However, the use of HU has been limited by its development of hematopoietic toxicity. In this study, the novel RR inhibitors didox (DX; 3,4-dihydroxybenzohydroxamic acid), and trimidox (TX; 3,4,5-trihydroxybenzamidoxime) were evaluated along with HU for anti-retroviral efficacy in LPBM5-induced retro-viral disease (MAIDS) both as monotherapeutic regimens and in combination with the guanine containing NRTI abacavir (ABC). Anti-retroviral drug efficacy was determined by measuring inhibition of splenomegaly, hypergammaglobulinemia, and splenic levels of proviral DNA. In this study, all RRIs tested showed the ability to improve the efficacy of ABC in the MAIDS model by reducing splenomegaly, hypergammaglobulinemia, and splenic proviral DNA levels. PMID:15130534

  13. Steroidal 5α-reductase and 17α-hydroxylase/17,20-lyase (CYP17) inhibitors useful in the treatment of prostatic diseases.

    Science.gov (United States)

    Salvador, Jorge A R; Pinto, Rui M A; Silvestre, Samuel M

    2013-09-01

    The role of steroidal inhibitors of androgen biosynthesis as potential weapons in the treatment of prostatic diseases, such as benign prostatic hyperplasia and prostatic cancer will be reviewed. Two enzymes have been targeted in the development of inhibitors that potentially could be useful in the management of such conditions. 5α-Reductase is primarily of interest in benign prostatic disease, though some role in the chemoprevention of prostatic carcinoma have been considered, whereas the 17α-hydroxylase/17,20-lyase (CYP17) enzyme is of interest in the treatment of malignant disease. An overview of the main achievements obtained during the past years will be presented, however special focus will be made on steroidal molecules that reached clinical trials or have been commercially launched. Relevant examples of such drugs are finasteride, dutasteride, abiraterone acetate and galeterone (TOK-001, formerly known as VN/124-1). This article is part of a Special Issue entitled "Synthesis and biological testing of steroid derivatives as inhibitors". PMID:23688836

  14. Pyrazole inhibitors of HMG-CoA reductase: an attempt to dramatically reduce synthetic complexity through minimal analog re-design.

    Science.gov (United States)

    Larsen, Scott D; Poel, Toni-Jo; Filipski, Kevin J; Kohrt, Jeffrey T; Pfefferkorn, Jeffrey A; Sorenson, Roderick J; Tait, Bradley D; Askew, Valerie; Dillon, Lisa; Hanselman, Jeffrey C; Lu, Gina H; Robertson, Andrew; Sekerke, Catherine; Kowala, Mark C; Auerbach, Bruce J

    2007-10-15

    An extraordinarily potent and hepatoselective class of HMG-CoA reductase inhibitors containing a pyrazole core was recently reported; however, its development was hampered by a long and difficult synthetic route. We attempted to circumvent this obstacle by preparing closely related analogs wherein the key dihydroxyheptanoic acid sidechain was tethered to the pyrazole core via an oxygen linker ('oxypyrazoles'). This minor change reduced the total number of synthetic steps from 14 to 7. Although the resulting analogs maintained much of the in vitro and cell activity of the pyrazoles, inferior in vivo activity precluded further development. Caco-2 cell permeability data suggest that enhanced cellular efflux of the oxypyrazoles relative to the pyrazoles may be responsible for the poor in vivo activity. PMID:17764936

  15. The 5α-reductase inhibitor Dutasteride but not Finasteride protects dopamine neurons in the MPTP mouse model of Parkinson's disease.

    Science.gov (United States)

    Litim, Nadhir; Bourque, Mélanie; Al Sweidi, Sara; Morissette, Marc; Di Paolo, Thérèse

    2015-10-01

    Finasteride and Dutasteride are 5α-reductase inhibitors used in the clinic to treat endocrine conditions and were recently found to modulate brain dopamine (DA) neurotransmission and motor behavior. We investigated if Finasteride and Dutasteride have a neuroprotective effect in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) male mice as a model of Parkinson's disease (PD). Experimental groups included saline treated controls and mice treated with saline, Finasteride (5 and 12.5 mg/kg) or Dutasteride (5 and 12.5 mg/kg) for 5 days before and 5 days after MPTP administration (4 MPTP injections, 6.5 mg/kg on day 5 inducing a moderate DA depletion) and then they were euthanized. MPTP administration decreased striatal DA contents measured by HPLC while serotonin contents remained unchanged. MPTP mice treated with Dutasteride 5 and 12.5 mg/kg had higher striatal DA and metabolites (DOPAC and HVA) contents with a decrease of metabolites/DA ratios compared to saline-treated MPTP mice. Finasteride had no protective effect on striatal DA contents. Tyrosine hydroxylase (TH) mRNA levels measured by in situ hybridization in the substantia nigra pars compacta were unchanged. Dutasteride at 12.5 mg/kg reduced the effect of MPTP on specific binding to striatal DA transporter (DAT) and vesicular monoamine transporter 2 (VMAT2) measured by autoradiography. MPTP reduced compared to controls plasma testosterone (T) and dihydrotestosterone (DHT) concentrations measured by liquid chromatography-tandem mass spectrometry; Dutasteride and Finasteride increased plasma T levels while DHT levels remained low. In summary, our results showed that a 5α-reductase inhibitor, Dutasteride has neuroprotective activity preventing in male mice the MPTP-induced loss of several dopaminergic markers. PMID:26006269

  16. Synthesis and biological evaluation of 3-tetrazolo steroidal analogs: Novel class of 5α-reductase inhibitors.

    Science.gov (United States)

    Aggarwal, Saurabh; Mahapatra, Manoj Kumar; Kumar, Rajnish; Bhardwaj, Tilak R; Hartmann, Rolf W; Haupenthal, Jörg; Kumar, Manoj

    2016-02-15

    In the present study, a series of steroidal tetrazole derivatives of androstane and pregnane have been prepared in which the tetrazole moiety was appended at C-3 and 17a-aza locations. 3-Tetrazolo-3,5-androstadien-17-one (6), 3-tetrazolo-19-nor-3,5-androstadien-17-one (10), 3-tetrazolo-3,5-pregnadien-20-one (14), 17a-substituted 3-tetrazolo-17a-aza-D-homo-3,5-androstadien-17-one (26-31) and 3-(2-acetyltetrazolo)-17a-aza-d-homo-3,5-androstadien-17-one (32) were synthesized from dehydroepiandrosterone acetate (1) through multiple synthetic steps. Some of the synthesized compounds were evaluated for their in vitro 5α-reductase (5AR) inhibitory activity by measuring the conversion of [(3)H] androstenedione in human embryonic kidney (HEK) cells. In vivo 5α-reductase inhibitory activity also showed a significant reduction (p <0.05) in rat prostate weight. The most potent compound 14 showed 5AR-2 inhibition with IC50 being 15.6nM as compared to clinically used drug finasteride (40nM). There was also a significant inhibition of 5AR-1 with IC50 547nM compared to finasteride (453nM). PMID:26780831

  17. Aqueous Molecular Dynamics Simulations of the M. tuberculosis Enoyl-ACP Reductase-NADH System and Its Complex with a Substrate Mimic or Diphenyl Ethers Inhibitors

    Directory of Open Access Journals (Sweden)

    Camilo Henrique da Silva Lima

    2015-10-01

    Full Text Available Molecular dynamics (MD simulations of 12 aqueous systems of the NADH-dependent enoyl-ACP reductase from Mycobacterium tuberculosis (InhA were carried out for up to 20–40 ns using the GROMACS 4.5 package. Simulations of the holoenzyme, holoenzyme-substrate, and 10 holoenzyme-inhibitor complexes were conducted in order to gain more insight about the secondary structure motifs of the InhA substrate-binding pocket. We monitored the lifetime of the main intermolecular interactions: hydrogen bonds and hydrophobic contacts. Our MD simulations demonstrate the importance of evaluating the conformational changes that occur close to the active site of the enzyme-cofactor complex before and after binding of the ligand and the influence of the water molecules. Moreover, the protein-inhibitor total steric (ELJ and electrostatic (EC interaction energies, related to Gly96 and Tyr158, are able to explain 80% of the biological response variance according to the best linear equation, pKi = 7.772 − 0.1885 × Gly96 + 0.0517 × Tyr158 (R2 = 0.80; n = 10, where interactions with Gly96, mainly electrostatic, increase the biological response, while those with Tyr158 decrease. These results will help to understand the structure-activity relationships and to design new and more potent anti-TB drugs.

  18. Aqueous Molecular Dynamics Simulations of the M. tuberculosis Enoyl-ACP Reductase-NADH System and Its Complex with a Substrate Mimic or Diphenyl Ethers Inhibitors

    Science.gov (United States)

    da Silva Lima, Camilo Henrique; de Alencastro, Ricardo Bicca; Kaiser, Carlos Roland; de Souza, Marcus Vinícius Nora; Rodrigues, Carlos Rangel; Albuquerque, Magaly Girão

    2015-01-01

    Molecular dynamics (MD) simulations of 12 aqueous systems of the NADH-dependent enoyl-ACP reductase from Mycobacterium tuberculosis (InhA) were carried out for up to 20–40 ns using the GROMACS 4.5 package. Simulations of the holoenzyme, holoenzyme-substrate, and 10 holoenzyme-inhibitor complexes were conducted in order to gain more insight about the secondary structure motifs of the InhA substrate-binding pocket. We monitored the lifetime of the main intermolecular interactions: hydrogen bonds and hydrophobic contacts. Our MD simulations demonstrate the importance of evaluating the conformational changes that occur close to the active site of the enzyme-cofactor complex before and after binding of the ligand and the influence of the water molecules. Moreover, the protein-inhibitor total steric (ELJ) and electrostatic (EC) interaction energies, related to Gly96 and Tyr158, are able to explain 80% of the biological response variance according to the best linear equation, pKi = 7.772 − 0.1885 × Gly96 + 0.0517 × Tyr158 (R2 = 0.80; n = 10), where interactions with Gly96, mainly electrostatic, increase the biological response, while those with Tyr158 decrease. These results will help to understand the structure-activity relationships and to design new and more potent anti-TB drugs. PMID:26457706

  19. Effect of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibition on serum matrix metalloproteinase-13 and tissue inhibitor matrix metalloproteinase-1 levels as a sign of plaque stabilization.

    Science.gov (United States)

    Cevik, Cihan; Otahbachi, Mohammad; Nugent, Kenneth; Warangkana, Chokesuwattanaskul; Meyerrose, Gary

    2008-12-01

    Atherosclerotic plaques are composed of a lipid rich core, which is covered by a collagen rich fibrous cap. Rupture of the atherosclerotic plaque with superimposed thrombosis is the main cause of acute coronary syndromes, including acute myocardial infarction and unstable angina. The stability of the plaque depends on its collagen content; degradation of the collagen leads to a vulnerable plaque that is prone to rupture. Recent studies have demonstrated a critical role for matrix metalloproteinases (MMPs) in the degradation of the collagen content and the reduction of mechanical stability of the atherosclerotic plaques. Increased expression of various MMPs has been shown in the tissue sections of atherosclerotic plaques. The increased expression of MMPs in the atheroma also leads to increased MMP levels in the circulation. The cholesterol lowering drugs - 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) - decrease the tissue expression of various MMPs in atheromatous plaques by attenuating the inflammatory process that promotes MMP expression during the course of atherosclerosis. However, the effect of statin treatment on the serum levels of MMP-13, which has a critical role in the initiation of collagen degradation, is unknown. On the basis of these previous studies, we discuss the need for studies on the effect of statin treatment on the serum levels of MMP-13 and tissue inhibitor of matrix metalloproteinase (TIMP-1) levels in hypercholesterolemic patients. PMID:19001938

  20. Inhibition of geranylgeranylation mediates the effects of 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase inhibitors on microglia.

    Science.gov (United States)

    Bi, Xiaoning; Baudry, Michel; Liu, Jihua; Yao, Yueqin; Fu, Lawrence; Brucher, Fernando; Lynch, Gary

    2004-11-12

    Inflammatory responses involving microglia, the resident macrophages of the brain, are thought to contribute importantly to the progression of Alzheimer's disease (AD) and possibly other neurodegenerative disorders. The present study tested whether the mevalonate-isoprenoid biosynthesis pathway, which affects inflammation in many types of tissues, tonically regulates microglial activation. This question takes on added significance given the potential use of statins, drugs that block the rate-limiting step (3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase)) in mevalonate and cholesterol synthesis, in AD treatment. Both mevastatin and simvastatin caused a concentration- and time-dependent activation of microglia in cultured rat hippocampal slices. This response consisted of a transformation of the cells from a typical resting configuration to an amoeboid, macrophage-like morphology, increased expression of a macrophage antigen, and up-regulation of the cytokine tumor necrosis factor-alpha. Evidence for proliferation was also obtained. Statin-induced microglial changes were blocked by mevalonate but not by cholesterol, indicating that they were probably due to suppression of isoprenoid synthesis. In accord with this, the statin effects were absent in slices co-incubated with geranylgeranyl pyrophosphate, a mevalonate product that provides for the prenylation of Rho GTPases. Finally, PD98089, a compound that blocks activation of extracellularly regulated kinases1/2, suppressed statin-induced up-regulation of tumor necrosis factor-alpha but had little effect on microglial transformation. These results suggest that 1) the mevalonate-isoprenoid pathway is involved in regulating microglial morphology and in controlling expression of certain cytokines and 2) statins have the potential for enhancing a component of AD with uncertain relationships to other features of the disease. PMID:15364922

  1. Isomerisation of c4-c6 aldoses with zeolites

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to isomerization of C4-C6 aldoses to their corresponding C4-C6 ketoses. In particular, the invention concerns isomerization of C4-C6 aldoses over solid zeolite catalysts free of any metals other than aluminum, in the presence of suitable solvent(s) at suitable elevat...... the catalyst. The ketoses obtained are used as sweeteners in the food and/or brewery industry, or treated to obtain downstream platform chemicals such as lactic acid, HMF, levulinic acid, furfural, MMHB, and the like....

  2. Synthesis and biological evaluation of novel inhibitors against 1,3,8-trihydroxynaphthalene reductase from Magnaporthe grisea.

    Science.gov (United States)

    Chen, Haifeng; Han, Xinya; Qin, Nian; Wei, Lin; Yang, Yue; Rao, Li; Chi, Bo; Feng, Lingling; Ren, Yanliang; Wan, Jian

    2016-03-15

    1,3,8-Trihydroxynaphthalene reductase (3HNR) is an essential enzymes that is involved in fungal melanin biosynthesis. Based on the structural informations of active site of 3HNR, a series of β-nitrostyrene compounds were rationally designed and synthesized. The enzymatic activities of these compounds showed that most of them exhibited high inhibitory activities (<5.0 μM) against 3HNR; compound 3-2 exhibit the highest inhibitory activity (IC50=0.29 μM). In particular, some of these compounds had moderate fungicidal activity against Magnaporthe grisea. Compound 3-4 showed high in vivo activities against M. grisea (EC50=9.5 ppm). Furthermore, compound 3-2 was selected as a representative molecule, and the probable binding mode of this compound and the surrounding residues in the active site of 3HNR was elucidated by using molecular dock. The positive results suggest that β-nitrostyrene derivatives are most likely to be promising leads toward the discovery of novel agent of rice blast. PMID:26860927

  3. Is Transforming Growth Factor-β Signaling Activated in Human Hypertrophied Prostate Treated by 5-Alpha Reductase Inhibitor?

    OpenAIRE

    Jong Kwan Park; Do Sung Kim; Chen Zhao; Bo Ram Choi; Han Jung Chae; Hye Kyung Kim

    2013-01-01

    Background and Aim. It is well known that androgen deprivation relates to penile fibrosis, so we hypothesize that long-term treatment with 5-alphareductase inhibitors (5ARIs) may increase the risk of fibrosis of prostate. Patients and Methods. Thirty-two BPH patients who underwent transurethral resection of the prostate were enrolled. The patients were divided into two groups: group one, 16 patients underwent TURP who had been treated with tamsulosin for 2 years; group two, 16 patients underw...

  4. Theoretische und experimentelle Untersuchungen zur Inhibition des Enzyms Aldose Reduktase

    OpenAIRE

    Krämer, Oliver

    2004-01-01

    Thema der vorliegenden Arbeit war die Untersuchung der Inhibition des Enzyms Aldose Reduktase. Eine Besonderheit dieses Enzyms liegt in der ausgeprägten Anpassungsfähigkeit der Bindetasche bei der Ligandenbindung. Das Ausmaß dieser Rezeptorflexibilität wurde durch den ausführlichen Vergleich bekannter Kristallstrukturen und mit Hilfe von molekulardynamischen Simulationen untersucht. Beim Vergleich der bekannten Kristallstrukturen ...

  5. Dehydration of Different Ketoses and Aldoses to 5-Hydroxymethylfurfural

    NARCIS (Netherlands)

    van Putten, Robert-Jan; Soetedjo, Jenny N. M.; Pidko, Evgeny A.; van der Waal, Jan C.; Hensen, Emiel J. M.; de Jong, Ed; Heeres, Hero J.

    2013-01-01

    5-Hydroxymethylfurfural (HMF) is considered an important building block for future bio-based chemicals. Here, we present an experimental study using different ketoses (fructose, sorbose, tagatose) and aldoses (glucose, mannose, galactose) under aqueous acidic conditions (65gL(-1) substrate, 100-160

  6. Computer-Aided Design of Orally Bioavailable Pyrrolidine Carboxamide Inhibitors of Enoyl-Acyl Carrier Protein Reductase of Mycobacterium tuberculosis with Favorable Pharmacokinetic Profiles

    Directory of Open Access Journals (Sweden)

    Affiba Florance Kouassi

    2015-12-01

    Full Text Available We have carried out a computational structure-based design of new potent pyrrolidine carboxamide (PCAMs inhibitors of enoyl-acyl carrier protein reductase (InhA of Mycobacterium tuberculosis (MTb. Three-dimensional (3D models of InhA-PCAMx complexes were prepared by in situ modification of the crystal structure of InhA-PCAM1 (Protein Data Bank (PDB entry code: 4U0J, the reference compound of a training set of 20 PCAMs with known experimental inhibitory potencies (IC50exp. First, we built a gas phase quantitative structure-activity relationships (QSAR model, linearly correlating the computed enthalpy of the InhA-PCAM complex formation and the IC50exp. Further, taking into account the solvent effect and loss of inhibitor entropy upon enzyme binding led to a QSAR model with a superior linear correlation between computed Gibbs free energies (ΔΔGcom of InhA-PCAM complex formation and IC50exp (pIC50exp = −0.1552·ΔΔGcom + 5.0448, R2 = 0.94, which was further validated with a 3D-QSAR pharmacophore model generation (PH4. Structural information from the models guided us in designing of a virtual combinatorial library (VL of more than 17 million PCAMs. The VL was adsorption, distribution, metabolism and excretion (ADME focused and reduced down to 1.6 million drug like orally bioavailable analogues and PH4 in silico screened to identify new potent PCAMs with predicted IC50pre reaching up to 5 nM. Combining molecular modeling and PH4 in silico screening of the VL resulted in the proposed novel potent antituberculotic agent candidates with favorable pharmacokinetic profiles.

  7. Evaluating thermodynamic integration performance of the new amber molecular dynamics package and assess potential halogen bonds of enoyl-ACP reductase (FabI) benzimidazole inhibitors.

    Science.gov (United States)

    Su, Pin-Chih; Johnson, Michael E

    2016-04-01

    Thermodynamic integration (TI) can provide accurate binding free energy insights in a lead optimization program, but its high computational expense has limited its usage. In the effort of developing an efficient and accurate TI protocol for FabI inhibitors lead optimization program, we carefully compared TI with different Amber molecular dynamics (MD) engines (sander and pmemd), MD simulation lengths, the number of intermediate states and transformation steps, and the Lennard-Jones and Coulomb Softcore potentials parameters in the one-step TI, using eleven benzimidazole inhibitors in complex with Francisella tularensis enoyl acyl reductase (FtFabI). To our knowledge, this is the first study to extensively test the new AMBER MD engine, pmemd, on TI and compare the parameters of the Softcore potentials in the one-step TI in a protein-ligand binding system. The best performing model, the one-step pmemd TI, using 6 intermediate states and 1 ns MD simulations, provides better agreement with experimental results (RMSD = 0.52 kcal/mol) than the best performing implicit solvent method, QM/MM-GBSA from our previous study (RMSD = 3.00 kcal/mol), while maintaining similar efficiency. Briefly, we show the optimized TI protocol to be highly accurate and affordable for the FtFabI system. This approach can be implemented in a larger scale benzimidazole scaffold lead optimization against FtFabI. Lastly, the TI results here also provide structure-activity relationship insights, and suggest the parahalogen in benzimidazole compounds might form a weak halogen bond with FabI, which is a well-known halogen bond favoring enzyme. © 2015 Wiley Periodicals, Inc. PMID:26666582

  8. Tissue-selective acute effects of inhibitors of 3-hydroxy-3-methyl glutaryl coenzyme A reductase on cholesterol biosynthesis in lens

    International Nuclear Information System (INIS)

    To evaluate the effects of lovastatin, simvastatin and pravastatin on cholesterol synthesis in the lens, we developed a facile, reproducible ex-vivo assay using lenses from wean ling rats explanted to tissue culture medium. [14 C] acetate incorporation into cholesterol was proportional to time and to the number of lenses in the incubation and was completely eliminated by high concentrations of inhibitors of HMG-CoA reductase. At the same time, incorporation into free fatty acids was not inhibited, In market contrast to the liver, the dose-response curve for pravastatin in lens was shifted two orders of magnitude to the right of the curves for lovastatin acid and simvastatin acid. The calculated I C50 values were 4.5 ± 0.7 nM, 5.2 ± 1.5 nM, and 469 ± 42 nM for lovastatin acid, simvastatin acid, and pravastatin, respectively. Thus, while equally active in the liver, pravastatin was 100-fold less inhibitory in the lens compared to lovastatin and simvastatin. Similar selectivity was observed with rabbit lens. Following oral dosing, ex vivo inhibition of [14 C] acetate incorporation into cholesterol in rat liver was similar for lovastatin and pravastatin, but cholesterol synthesis is in lens was inhibited by lovastatin by as much as 70%. This inhibition was dose-dependent and no inhibition in lens was observed with pravastatin even at very high doses. (author)

  9. A systematic review of the effects and mechanisms of preoperative 5α-reductase inhibitors on intraoperative haemorrhage during surgery for benign prostatic hyperplasia

    Institute of Scientific and Technical Information of China (English)

    Huan-Tao Zong; Xiao-Xia Peng; Chen-Chen Yang; Yong Zhang

    2011-01-01

    5α-reductase inhibitors (5α-RIs),including finasteride and dutasteride,are commonly used medical therapies for benign prostatic hyperplasia (BPH).Many studies reported that preoperative 5α-RI had impact on intraoperative haemorrhage during surgery for BPH,but it was still in controversial.So,we conducted a systematic review of the effects and mechanisms of 5α-RIs on intraoperative bleeding for BPH.MEDLINE,EMBASE,the Cochrane Controlled Trail Register of Controlled Trials and the reference lists of retrieved studies were searched in the analysis.Sixteen publications involving 15 different randomized controlled trials (RCTs) and a total of 1156 patients were used in the analysis,including 10 RCTs for finasteride and five RCTs for dutasteride.We found that preoperative finasteride treatment decreases microvessel density (MVD) in resected prostate specimens.Total blood loss,blood loss per gram of resected prostate tissue and decreases in haemoglobin were all greatly reduced in the finasteride group as compared to controls.Dutasteride appeared to have no effect on bleeding.This meta-analysis shows that preoperative finasteride treatment could decrease intraoperative haemorrhage during surgery for BPH.Preoperative dutasteride had no effect on intraoperative haemorrhage,but further high-quality prospective studies are still needed to confirm this observation.

  10. A systematic review of the effects and mechanisms of preoperative 5α-reductase inhibitors on intraoperative haemorrhage during surgery for benign prostatic hyperplasia.

    Science.gov (United States)

    Zong, Huan-Tao; Peng, Xiao-Xia; Yang, Chen-Chen; Zhang, Yong

    2011-11-01

    5α-reductase inhibitors (5α-RIs), including finasteride and dutasteride, are commonly used medical therapies for benign prostatic hyperplasia (BPH). Many studies reported that preoperative 5α-RI had impact on intraoperative haemorrhage during surgery for BPH, but it was still in controversial. So, we conducted a systematic review of the effects and mechanisms of 5α-RIs on intraoperative bleeding for BPH. MEDLINE, EMBASE, the Cochrane Controlled Trail Register of Controlled Trials and the reference lists of retrieved studies were searched in the analysis. Sixteen publications involving 15 different randomized controlled trials (RCTs) and a total of 1156 patients were used in the analysis, including 10 RCTs for finasteride and five RCTs for dutasteride. We found that preoperative finasteride treatment decreases microvessel density (MVD) in resected prostate specimens. Total blood loss, blood loss per gram of resected prostate tissue and decreases in haemoglobin were all greatly reduced in the finasteride group as compared to controls. Dutasteride appeared to have no effect on bleeding. This meta-analysis shows that preoperative finasteride treatment could decrease intraoperative haemorrhage during surgery for BPH. Preoperative dutasteride had no effect on intraoperative haemorrhage, but further high-quality prospective studies are still needed to confirm this observation. PMID:21892196

  11. A novel aldose-aldose oxidoreductase for co-production of D-xylonate and xylitol from D-xylose with Saccharomyces cerevisiae.

    Science.gov (United States)

    Wiebe, Marilyn G; Nygård, Yvonne; Oja, Merja; Andberg, Martina; Ruohonen, Laura; Koivula, Anu; Penttilä, Merja; Toivari, Mervi

    2015-11-01

    An open reading frame CC1225 from the Caulobacter crescentus CB15 genome sequence belongs to the Gfo/Idh/MocA protein family and has 47 % amino acid sequence identity with the glucose-fructose oxidoreductase from Zymomonas mobilis (Zm GFOR). We expressed the ORF CC1225 in the yeast Saccharomyces cerevisiae and used a yeast strain expressing the gene coding for Zm GFOR as a reference. Cell extracts of strains overexpressing CC1225 (renamed as Cc aaor) showed some Zm GFOR type of activity, producing D-gluconate and D-sorbitol when a mixture of D-glucose and D-fructose was used as substrate. However, the activity in Cc aaor expressing strain was >100-fold lower compared to strains expressing Zm gfor. Interestingly, C. crescentus AAOR was clearly more efficient than the Zm GFOR in converting in vitro a single sugar substrate D-xylose (10 mM) to xylitol without an added cofactor, whereas this type of activity was very low with Zm GFOR. Furthermore, when cultured in the presence of D-xylose, the S. cerevisiae strain expressing Cc aaor produced nearly equal concentrations of D-xylonate and xylitol (12.5 g D-xylonate l(-1) and 11.5 g D-xylitol l(-1) from 26 g D-xylose l(-1)), whereas the control strain and strain expressing Zm gfor produced only D-xylitol (5 g l(-1)). Deletion of the gene encoding the major aldose reductase, Gre3p, did not affect xylitol production in the strain expressing Cc aaor, but decreased xylitol production in the strain expressing Zm gfor. In addition, expression of Cc aaor together with the D-xylonolactone lactonase encoding the gene xylC from C. crescentus slightly increased the final concentration and initial volumetric production rate of both D-xylonate and D-xylitol. These results suggest that C. crescentus AAOR is a novel type of oxidoreductase able to convert the single aldose substrate D-xylose to both its oxidized and reduced product. PMID:26264136

  12. Aldose-ketose interconversion in pyridine in the presence of aluminium oxide.

    Science.gov (United States)

    Ekeberg, Dag; Morgenlie, Svein; Stenstrøm, Yngve

    2007-10-15

    The reaction rate of the Lobry de Bruyn-Alberda van Ekenstein transformation of aldoses to ketoses in boiling pyridine was strongly increased by the addition of aluminium oxide. In addition to aldose-ketose transformation, 2-epimers of the starting aldoses and 3-epimers of the primarily produced ketoses were formed to some extent, as reported also when these reactions are carried out without aluminium oxide. The relative amounts of the primary ketose and the starting aldose in the reaction mixtures may be explained on the basis of their stability, predicted from reported free energy calculations. Isomerisation of ketoses to aldoses was much slower than the reverse reaction. The relative free energies are also in these cases important, the very stable xylo-2-hexulose gave only 7% and 6% of the aldoses gulose and idose, respectively, after boiling for 7h in pyridine in the presence of aluminium oxide. PMID:17606255

  13. Is Transforming Growth Factor-β Signaling Activated in Human Hypertrophied Prostate Treated by 5-Alpha Reductase Inhibitor?

    Directory of Open Access Journals (Sweden)

    Hye Kyung Kim

    2013-01-01

    Full Text Available Background and Aim. It is well known that androgen deprivation relates to penile fibrosis, so we hypothesize that long-term treatment with 5-alphareductase inhibitors (5ARIs may increase the risk of fibrosis of prostate. Patients and Methods. Thirty-two BPH patients who underwent transurethral resection of the prostate were enrolled. The patients were divided into two groups: group one, 16 patients underwent TURP who had been treated with tamsulosin for 2 years; group two, 16 patients underwent TURP who had been treated with combination of tamsulosin and dutasteride for at least 1 year. We evaluated the expressions of nNOS, iNOS, eNOS, TGF-β1, TGF-β2, phosphorylated-Smad2/3 (p-Smad2/3, E-cadherin, N-cadherin, and α-smooth muscle actin in the resected prostate tissues by western blotting, and the TGF-β concentration was determined by ELISA kit. Results. The expressions of 3 isoforms of NOS were significantly increased in group 2 except of eNOS in lateral prostate, and the expressions of TGF-β1, TGF-β2, and p-Smad2/3 increased about 2-fold compared with group 1. In group 2, the E-cadherin expression decreased while N-cadherin expression increased significantly. Conclusions. The overexpression of nNOS may contribute to prostate smooth muscle relaxation; however, long-time treatment with 5 ARI increases the risk of fibrosis of prostate.

  14. X-ray structure of the ternary MTX·NADPH complex of the anthrax dihydrofolate reductase: A pharmacophore for dual-site inhibitor design

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, Brad C.; Wan, Qun; Ahmad, Md Faiz; Langan, Paul; Dealwis, Chris G.; (Case Western); (LANL)

    2009-11-18

    For reasons of bioterrorism and drug resistance, it is imperative to identify and develop new molecular points of intervention against anthrax. Dihydrofolate reductase (DHFR) is a highly conserved enzyme and an established target in a number of species for a variety of chemotherapeutic programs. Recently, the crystal structure of B. anthracis DHFR (baDHFR) in complex with methotrexate (MTX) was determined and, based on the structure, proposals were made for drug design strategies directed against the substrate binding site. However, little is gleaned about the binding site for NADPH, the cofactor responsible for hydride transfer in the catalytic mechanism. In the present study, X-ray crystallography at 100 K was used to determine the structure of baDHFR in complex with MTX and NADPH. Although the NADPH binding mode is nearly identical to that seen in other DHFR ternary complex structures, the adenine moiety adopts an off-plane tilt of nearly 90 deg. and this orientation is stabilized by hydrogen bonds to functionally conserved Arg residues. A comparison of the binding site, focusing on this region, between baDHFR and the human enzyme is discussed, with an aim at designing species-selective therapeutics. Indeed, the ternary model, refined to 2.3{angstrom} resolution, provides an accurate template for testing the feasibility of identifying dual-site inhibitors, compounds that target both the substrate and cofactor binding site. With the ternary model in hand, using in silico methods, several compounds were identified which could potentially form key bonding contacts in the substrate and cofactor binding sites. Ultimately, two structurally distinct compounds were verified that inhibit baDHFR at low {mu}M concentrations. The apparent K{sub d} for one of these, (2-(3-(2-(hydroxyimino)-2-(pyridine-4-yl)-6,7-dimethylquinoxalin-2-yl)-1-(pyridine-4-yl)ethanone oxime), was measured by fluorescence spectroscopy to be 5.3 {mu}M.

  15. Potent increased risk of the initiation of DNA replication in human prostate cancer with the use of 5α-reductase inhibitors.

    Science.gov (United States)

    Kosaka, Takeo; Yasumizu, Yota; Miyazaki, Yasumasa; Miyajima, Akira; Kikuchi, Eiji; Oya, Mototsugu

    2014-01-01

    Recent clinical studies have raised the clinically important question of the relationship between dihydrotestosterone (DHT) and prostate cancer (PCa) progression. The significance of DHT or 5α-reductase inhibitors (5ARI) in PCa development and progression has not yet been fully characterized. The aim of this study was to determine whether the initiation of DNA replication was influenced by DHT in PCa. Three cell lines were used. LNCaP: a human PCa cell line that exhibits androgen-dependent proliferation, C4-2: a human PCa cell line that exhibits androgen-independent proliferation, and C4-2AT6: a castration resistant prostate cancer cell line. Two 5ARIs, finasteride and dutasteride, were used. We examined the mRNA expression of the components of pre-replication complex (Pre-RC), CDC6, CDT1, and MCM2-7. DHT induced cell proliferation of LNCaP accompanied by significantly increased CDC6, CDT1, and MCM2-7 expression. In contrast to LNCaP, DHT inhibited cell proliferation in C4-2AT6 cells accompanied by decreased expression of CDC6, CDT1, and MCM2-7. These reverse effects resemble the effects of 5ARIs in Pre-RC. Treatment with finasteride or dutasteride inhibited CDC6 expression in LNCaP, but both 5ARIs induced CDC6 expression in C4-2 and C4-2AT6 cells.These results indicate that DHT showed reversal effects on PCa cell proliferation among prostate cancer cells based on androgen-dependence, accompanied by regulation of the initiation of DNA replication. 5ARIs may modulate the DNA replication system in someaggressive PCa through up-regulation of CDC6 expression. PMID:25374915

  16. Angiotensin converting enzyme inhibitor and HMG-CoA reductase inhibitor as adjunct treatment for persons with HIV infection: a feasibility randomized trial.

    Directory of Open Access Journals (Sweden)

    Jason V Baker

    Full Text Available BACKGROUND: Treatments that reduce inflammation and cardiovascular disease (CVD risk among individuals with HIV infection receiving effective antiretroviral therapy (ART are needed. DESIGN AND METHODS: We conducted a 2 × 2 factorial feasibility study of lisinopril (L (10 mg daily vs L-placebo in combination with pravastatin (P (20 mg daily vs P-placebo among participants receiving ART with undetectable HIV RNA levels, a Framingham 10 year risk score (FRS ≥ 3%, and no indication for ACE-I or statin therapy. Tolerability and adherence were evaluated. Longitudinal mixed models assessed changes in blood pressure (BP, blood lipids, and inflammatory biomarkers from baseline through months 1 and 4. RESULTS: Thirty-seven participants were randomized and 34 [lisinopril/pravastatin (n=9, lisinopril/P-placebo (n=8, L-placebo/pravastatin (n=9, L-placebo/P-placebo (n=8] attended at least one follow-up visit. Participants were 97% male, 41% white, 67% were current smokers, and 65% were taking a protease inhibitor. Median age was 48 years, CD4 count 483 cells/mm(3, FRS 7.79%, total cholesterol 184 mg/dL, and LDL-C 95 mg/dL. There was no treatment difference for pravastatin vs P-placebo in total cholesterol, LDL-C, or any of the inflammatory biomarkers. Participants randomized to lisinopril vs. L-placebo had significant declines in diastolic BP (-3.3 mmHg, p=0.05, hsCRP (-0.61 µg/mL, p=0.02 and TNF-α (-0.17 pg/mL, p=0.04. Participants taking lisinopril vs L-placebo were more likely to report missed doses (88 vs 35%; p=0.001 and have adherence <90% by pill count (42 vs. 0%; p=0.02. Few participants from either group reported side effects (n=3 vs. n=1. CONCLUSIONS: The modest BP changes and decreased adherence with lisinopril and absence of lipid differences with pravastatin suggest future studies of these drug classes should consider a run-in period to assess adherence and use a different statin. Our results also indicate that ACE-I therapy may have anti

  17. Crystal structure of enoyl–acyl carrier protein reductase (FabK) from Streptococcus pneumoniae reveals the binding mode of an inhibitor

    OpenAIRE

    Saito, Jun; Yamada, Mototsugu; Watanabe, Takashi; Iida, Maiko; Kitagawa, Hideo; Takahata, Sho; Ozawa, Tomohiro; Takeuchi, Yasuo; Ohsawa, Fukuichi

    2008-01-01

    Enoyl–acyl carrier protein (ACP) reductases are critical for bacterial type II fatty acid biosynthesis and thus are attractive targets for developing novel antibiotics. We determined the crystal structure of enoyl–ACP reductase (FabK) from Streptococcus pneumoniae at 1.7 Å resolution. There was one dimer per asymmetric unit. Each subunit formed a triose phosphate isomerase (TIM) barrel structure, and flavin mononucleotide (FMN) was bound as a cofactor in the active site. The overall structure...

  18. Effect of Shifting from Combination Therapy to Monotherapy of α-Blockers or 5α-Reductase Inhibitors on Prostate Volume and Symptoms in Patients with Benign Prostatic Hyperplasia

    OpenAIRE

    Kim, Hyoung Woo; Moon, Dae Geun; Kim, Hyun Min; Hwang, Jong Ho; Kim, Soon Chan; Nam, Sam Geuk; Park, Jun Tag

    2011-01-01

    Purpose Combination therapy of α-blockers and 5α-reductase inhibitors (5-ARIs) is widely used for the treatment of benign prostatic hyperplasia (BPH). We aimed to study the effect on prostate volume and symptoms of shifting to monotherapy in patients who previously received a combination therapy. Materials and Methods A prospective study was conducted of 60 patients who were diagnosed with BPH. Patients were aged 45 years or older and had a prostate volume of 30 cc or more, International Pros...

  19. Antitumor and apoptosis promoting properties of atorvastatin, an inhibitor of HMG-CoA reductase, against Dalton's Lymphoma Ascites tumor in mice.

    Science.gov (United States)

    Ajith, Thekkoottuparambil Ananthanarayanan; Anu, Vijayan; Riji, Thomas

    2008-01-01

    Epidemiological and experimental data indicate that high body fat or high dietary fat can be ascribed to the induction of human cancers. Increased level of products of lipid peroxidation and cholesterol-enriched lipid domains in the plasma membrane can favorthe malignant transformation of cells. An effective chemopreventive agent with hypolipaedemic effect will be worthwhile to intervene early in the process of carcinogenesis to eliminate the pre-malignant cells. Apoptotic promoting and antitumor activities of a HMG-Co A reductase inhibitor, atorvatstain were investigated. The antitumor activity was evaluated using Daltons' Lymphoma Ascites (DLA) cell line transplanted ascites tumor model in mice. Proapoptotic activity was evaluated in DLA cell line induced ascites animals after the treatment of atorvastatin (4 and 16 mg/kg, i.p). Apoptosis was analyzed morphologically by staining with giemsa and biochemically by observing the laddering of DNA in agarose gel electrophoresis. In vitro short term cytotoxic activity of atorvatstain was studied by trypan blue dye exclusion method. Doxorubicin was used as the reference standard. Atorvastatin significantly (P growth at 16 mg/kg body wt (i.p). The percent increase in life span (%ILS) in the 16 mg/kg treated group was 41.1%. Single dose of atorvastatin (16 mg/kg body wt) was also effective to promote the apoptosis of DLA cells in the ascites tumor bearing mice that was evident from the multiple fragmentation of DNA in agarose gel electrophoresis. Further the morphological analysis of DLA cells aspirated from the atorvastatin treated ascites tumor bearing animals showed 36.34 +/- 6.78% apoptotic cells compared to the control animals (10.50 +/- 3.53%). Concentration of atorvastatin required for the 50% of the cytotoxicity was 30 +/- 2 microg/ml. Results of the study concluded that the antitumor activity of atorvastatin may be due to its proapoptotic and cytotoxic activities. These pleiotropic activities of the hypolipedaemic

  20. 5α-Reductase inhibitors alter steroid metabolism and may contribute to insulin resistance, diabetes, metabolic syndrome and vascular disease: a medical hypothesis.

    Science.gov (United States)

    Traish, Abdulmaged M; Guay, Andre T; Zitzmann, Michael

    2014-12-01

    5α-reductases, a unique family of enzymes with a wide host of substrates and tissue distributions, play a key role in the metabolism of androgens, progestins, mineralocorticoids and glucocorticoids. These enzymes are the rate-limiting step in the synthesis of a host of neurosteroids, which are critical for central nervous system function. Androgens and glucocorticoids modulate mitochondrial function, carbohydrate, protein and lipid metabolism and energy balance. Thus, the inhibition of these regulatory enzymes results in an imbalance in steroid metabolism and clearance rates, which leads to altered physiological processes. In this report, we advance the hypothesis that inhibition of 5α-reductases by finasteride and dutasteride alters not only steroid metabolism but also interferes with the downstream actions and signaling of these hormones. We suggest that finasteride and dutasteride inhibit 5α-reductase activities and reduce the clearance of glucocorticoids and mineralocorticoids, potentiating insulin resistance, diabetes and vascular disease. PMID:25460297

  1. The Effect of Halogen-to-Hydrogen Bond Substitution on Human Aldose Reductase Inhibition

    Czech Academy of Sciences Publication Activity Database

    Fanfrlík, Jindřich; Ruiz, F. X.; Kadlčíková, Aneta; Řezáč, Jan; Cousido-Siah, A.; Mitschler, A.; Haldar, Susanta; Lepšík, Martin; Kolář, Michal H.; Majer, Pavel; Podjarny, A. D.; Hobza, Pavel

    2015-01-01

    Roč. 10, č. 7 (2015), s. 1637-1642. ISSN 1554-8929 R&D Projects: GA ČR GBP208/12/G016 Grant ostatní: GA MŠk(CZ) ED2.1.00/03.0058 Institutional support: RVO:61388963 Keywords : drug desing * sigma-holes * binding Subject RIV: CE - Biochemistry Impact factor: 5.331, year: 2014

  2. Effect of aldose reductase in an animal model of oxygen-induced retinopathy

    OpenAIRE

    Fu, Zhongjie; 傅中捷.

    2012-01-01

     Retinopathy of prematurity (ROP) commonly occurs in premature babies, with the first phase of vessel cessation followed by a second phase of vessel proliferation. In addition to vascular changes, neuronal abnormalities have also been observed. However, evidence for morphological changes of retinal neurons at the cellular level is lacking. Oxidative stress has been highly indicated in the pathogenesis of ROP. Increased oxidative stress level was demonstrated in preterm babies expec...

  3. NADPH-dependent D-aldose reductases and xylose fermentation in Fusarium oxysporum

    DEFF Research Database (Denmark)

    Panagiotou, Gianni; Christakopoulos, P.

    2004-01-01

    reactors. Oxygen limitation had considerable influence on xylose metabolism. Under anaerobic conditions (0 vvm), xylitol was the main product with a maximum yield of 0.34 mole of xylitol/mole of xylose while the maximum ethanol yield (1.02 moles of ethanol/mole of xylose) was obtained under aerobic...... conditions (0.3 vvm). When the artificial electron acceptor acetoin was added to an anaerobic batch fermentation of xylose by F. oxysporum, the ethanol yield increased while xylitol excretion was also decreased....

  4. Synthesis and in vitro activity of some epimeric 20 alpha-hydroxy, 20-oxime and aziridine pregnene derivatives as inhibitors of human 17 alpha-hydroxylase/C17,20-lyase and 5 alpha-reductase.

    Science.gov (United States)

    Ling, Y Z; Li, J S; Kato, K; Liu, Y; Wang, X; Klus, G T; Marat, K; Nnane, I P; Brodie, A M

    1998-10-01

    Some epimeric 20-hydroxy, 20-oxime, 16 alpha, 17 alpha-, 17,20- and 20,21-aziridine derivatives of progesterone were synthesized and evaluated as inhibitors of human 17 alpha-hydroxylase/C17,20-lyase (P450(17) alpha) and 5 alpha-reductase (5 alpha-R). The reduction of 16-dehydropregenolone acetate (3a) was reinvestigated. NaBH4 in the presence of CeCl3 gave better stereo-selectivity for 20 beta-ol [20 alpha/20 beta-OH (4 alpha/4 beta) = 1/2.7] than LTBAH or the Meerwein-Pondroff method reported; reduction with Zn in HOAc formed exclusively 20 alpha-ol (4 alpha b). The 20 alpha- and 20 beta-hydroxy-4,16-pregnadien-3-one (9 alpha) and (9 beta) were synthesized from the alcohols 4 alpha b and 4 beta b. Several 20-oxime pregnadienes and 16 alpha, 17 alpha-, 17,20- and 20,21-aziridinyl-5-pregnene derivatives were also synthesized. LiAlH4 reduction of the 16-en-20-oxime (12b) yielded 20 (R)-(13a) and 20(S)-17 alpha,20-aziridine (13b) and 20(R)-17 beta,20-aziridine (14a). Several compounds inhibited the human P450(17) alpha with greater potency than ketoconzole. The 5 alpha-R enzyme assay showed that while (9 alpha) did not have any activity, (9 beta) and (3b) were potent 5 alpha-reductase (IC50 = 21 and 31 nM) inhibitors with activities similar to finasteride. The 20-oximes (17a) and (17b) were potent dual inhibitors for both 5 alpha-R (IC50 = 63 and 115 nM, compared to 33 nM for finasteride) and P450(17) alpha (IC50 = 43 and 25 nM, compared to 78 nM for ketoconazole). PMID:9839000

  5. 8-Methoxy-naphtho[2,3-b]thiophen-4,9-quinone, a non-competitive inhibitor of trypanothione reductase

    Directory of Open Access Journals (Sweden)

    Zani Carlos L

    2003-01-01

    Full Text Available The enzyme trypanothione reductase is a recognised drug target in trypanosomatids and has been used in the search of new compounds with potential activity against diseases such as leishmaniasis, Chagas disease and African trypanosomiasis. 8-Methoxy-naphtho [2,3-b] thiophen-4,9-quinone was selected in a screening of natural and synthetic compounds using an in vitro assay with the recombinant enzyme from Trypanosoma cruzi. Its mode of inhibition fits a non-competitive model with respect to the substrate (trypanothione and to the co-factor (NADPH, with Ki-values of 5 and 3.6 µM, respectively. When tested against human glutathione reductase, this compound did not display any significant inhibition at 100 µM, indicating a good selectivity against the parasite enzyme.

  6. 1,8-Dihydroxynaphthalene (DHN)-Melanin Biosynthesis Inhibitors Increase Erythritol Production in Torula corallina, and DHN-Melanin Inhibits Erythrose Reductase

    OpenAIRE

    Lee, Jung-Kul; Jung, Hyung-Moo; Kim, Sang-Yong

    2003-01-01

    The yeast Torula corallina is a strong erythritol producer that is used in the industrial production of erythritol. However, melanin accumulation during culture represents a serious problem for the purification of erythritol from the fermentation broth. Melanin biosynthesis inhibitors such as 3,4-dihydroxyphenylalanine and 1,8-dihydroxynaphthalene (DHN)-melanin inhibitors were added to the T. corallina cultures. Only the DHN-melanin inhibitors showed an effect on melanin production, which sug...

  7. Inhibitors

    Science.gov (United States)

    ... wrong place in the body. Immune Tolerance Induction (ITI) Therapy: The goal of ITI therapy is to stop the inhibitor reaction from ... body to accept clotting factor concentrate treatments. With ITI therapy, people receive large amounts of clotting factor ...

  8. A Novel NADPH-Dependent Aldehyde Reductase Gene from Saccharomyces cerevisiae NRRL Y-12632 Involved in the Detoxification of Aldehyde Inhibitors Derived from Lignocellulosic Biomass Conversion

    Science.gov (United States)

    Aldehyde inhibitors such as furfural, 5-hydroxymethylfurfural (HMF), anisaldehyde, benzaldehyde, cinnamaldehyde, and phenylaldehyde are commonly generated during lignocellulosic biomass conversion process for low-cost cellulosic ethanol production that interferes with subsequent microbial growth and...

  9. Structural and Enzymatic Analyses Reveal the Binding Mode of a Novel Series of Francisella tularensis Enoyl Reductase (FabI) Inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Mehboob, Shahila; Hevener, Kirk E.; Truong, Kent; Boci, Teuta; Santarsiero, Bernard D.; Johnson, Michael E. (UIC)

    2012-10-10

    Because of structural and mechanistic differences between eukaryotic and prokaryotic fatty acid synthesis enzymes, the bacterial pathway, FAS-II, is an attractive target for the design of antimicrobial agents. We have previously reported the identification of a novel series of benzimidazole compounds with particularly good antibacterial effect against Francisella tularensis, a Category A biowarfare pathogen. Herein we report the crystal structure of the F. tularensis FabI enzyme in complex with our most active benzimidazole compound bound with NADH. The structure reveals that the benzimidazole compounds bind to the substrate site in a unique conformation that is distinct from the binding motif of other known FabI inhibitors. Detailed inhibition kinetics have confirmed that the compounds possess a novel inhibitory mechanism that is unique among known FabI inhibitors. These studies could have a strong impact on future antimicrobial design efforts and may reveal new avenues for the design of FAS-II active antibacterial compounds.

  10. EFFECT OF SYSTEMIC ADMINISTRATION OF HMG Co A REDUCTASE INHIBITOR ATORVASTATIN ON CENTRAL RETINAL ARTERY FLOW DYNAMICS, INTRA OCULAR PRESSURE AND VISUAL FIELD CHANGES IN PRIMARY OPEN ANGLE GLAUCOMA AND NORMAL TENSION GLAUCOMA PATIENTS

    Directory of Open Access Journals (Sweden)

    Deepak Kumar

    2015-12-01

    Full Text Available PURPOSE To study the effect of systemic administration of HMG CoA reductase inhibitor Atorvastatin on Central Retinal Artery (CRA flow dynamics, Intraocular Pressure (IOP and Visual Field (VF changes in Primary Open Angle Glaucoma (POAG and Normal Tension Glaucoma (NTG patients. MATERIALS AND METHODS Prospective randomized placebo controlled double blind parallel group study consisting of 80 eyes of 40 patients suffering from POAG and NTG was conducted. After baseline clinical evaluation and Color Doppler Imaging (CDI of CRA subjects were randomized to receive 40mg/day of Atorvastatin (Tonact or matching Placebo for 3 months and followed at two weeks, one month and three months. Main outcome measures were Peak Systolic Velocity (PSV, End Diastolic Velocity (EDV, Resistive Index (RI, IOP and Mean Deviation (MD in VF. RESULTS Atorvastatin group showed decrease in IOP (P=0.0009 in right eye and P=0.0049 in left eye and in RI (P=0.0005 in right eye and P=0.0008 in left eye, while there was increase in RI in the placebo group (P=0.0006 in right eye and P=0.0007 in left eye after 3 months. No significant change in MD of VF was noticed in both groups. CONCLUSION Atorvastatin has favorable effect in POAG and NTG patients causing decrease in IOP and resistance of CRA with increase in CRA flow dynamics.

  11. A PHASE I STUDY OF THE NOVEL RIBONUCLEOTIDE REDUCTASE INHIBITOR 3-AMINOPYRIDINE-2-CARBOXALDEHYDE THIOSEMICARBAZONE (3-AP, TRIAPINE®) IN COMBINATION WITH THE NUCLEOSIDE ANALOG FLUDARABINE FOR PATIENTS WITH REFRACTORY ACUTE LEUKEMIAS AND AGGRESSIVE MYELOPROLIFERATIVE DISORDERS

    Science.gov (United States)

    Karp, Judith E.; Giles, Francis J.; Gojo, Ivana; Morris, Lawrence; Greer, Jacqueline; Johnson, Bonny; Thein, Mya; Sznol, Mario; Low, Jennifer

    2009-01-01

    Triapine® is a potent ribonucleotide reductase (RR) inhibitor that depletes intracellular deoxyribonculeotide pools, especially dATP. We designed a Phase I trial of Triapine followed by the adenosine analog fludarabine in adults with refractory acute leukemias and aggressive myeloproliferative disorders (MPD). Two schedules were examined: A. Triapine 105mg/m2/day over 4 hours followed by fludarabine daily × 5 (24 patients, fludarabine 15–30 mg/m2/dose); B. Triapine 200mg/m2 over 24 hours followed by 5 days of fludarabine 30 mg/m2/day (9 patients). Complete and partial responses (CR,PR) occurred in Schedule A (5/24, 21%), with CR occurring at the 2 highest fludarabine doses (2/12, 17%). In contrast, no CR or PR occurred in Schedule B. Four of the 5 responses occurred in patients with underlying MPD (4/14, 29%). Drug-related toxicities included fever and metabolic acidosis. Triapine 105 mg/m2 followed by fludarabine 30mg/m2 daily × 5 is active in refractory myeloid malignancies and warrants continuing study for patients with aggressive MPD. PMID:17640728

  12. Substituted pyrazoles as hepatoselective HMG-CoA reductase inhibitors: discovery of (3R,5R)-7-[2-(4-fluoro-phenyl)-4-isopropyl-5-(4-methyl-benzylcarbamoyl)-2H-pyrazol-3-yl]-3,5-dihydroxyheptanoic acid (PF-3052334) as a candidate for the treatment of hypercholesterolemia.

    Science.gov (United States)

    Pfefferkorn, Jeffrey A; Choi, Chulho; Larsen, Scott D; Auerbach, Bruce; Hutchings, Richard; Park, William; Askew, Valerie; Dillon, Lisa; Hanselman, Jeffrey C; Lin, Zhiwu; Lu, Gina H; Robertson, Andrew; Sekerke, Catherine; Harris, Melissa S; Pavlovsky, Alexander; Bainbridge, Graeme; Caspers, Nicole; Kowala, Mark; Tait, Bradley D

    2008-01-10

    In light of accumulating evidence that aggressive LDL-lowering therapy may offer increased protection against coronary heart disease, we undertook the design and synthesis of a novel series of HMG-CoA reductase inhibitors based upon a substituted pyrazole template. Optimizing this series using both structure-based design and molecular property considerations afforded a class of highly efficacious and hepatoselective inhibitors resulting in the identification of (3 R,5 R)-7-[2-(4-fluoro-phenyl)-4-isopropyl-5-(4-methyl-benzylcarbamoyl)-2 H-pyrazol-3-yl]-3,5-dihydroxy-heptanoic (PF-3052334) as a candidate for the treatment of hypercholesterolemia. PMID:18072721

  13. 5α还原酶抑制剂在前列腺癌化学预防中的作用%Role of 5α-reductase Inhibitors in the Chemoprevention of Prostate Cancer

    Institute of Scientific and Technical Information of China (English)

    安超; 徐涛; 王晓峰

    2011-01-01

    Prostate cancer is one of the most common visceral malignancies in human. In recent years, its incidence has dramatically increased in China. 5a-reductase inhibitors can block the biological effects of dihydrotestesterone by restraining the transformation from testosterone to dihydrotestesterone, and therefore can be used for the chemoprevention of prostate cancer. Two large clinical trials on the chemopreven-ticn of prostate cancer (the Prostate Capcer Prevention Trial and the Reduction by Dutasteride of Prostate Cancer Events) were completed in 2003 and 2008 , respectively, bringing the global interests on this topic. However, the interpretations of these two trials and the possible recommendations on clinical applications remain controversial.%前列腺癌是人类最常见的内脏恶性肿瘤之一,近年我国的发病率呈逐年上升趋势,5α还原酶抑制剂通过抑制睾酮向二氢睾酮的转化,阻断二氢睾酮的生物学效应,因此可以作为前列腺癌的化学预防药物.完成于2003年及2008年的全世界最大规模的两项关于前列腺癌化学预防的大型临床试验——前列腺癌预防试验和度他雄胺减少前列腺癌事件试验,带来了前所未有的对前列腺癌化学预防的关注,但是学术界对上述试验的结论以及应该给予患者怎样的建议仍然存在争论.

  14. In vitro biliary clearance of angiotensin II receptor blockers and 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors in sandwich-cultured rat hepatocytes: comparison with in vivo biliary clearance.

    Science.gov (United States)

    Abe, Koji; Bridges, Arlene S; Yue, Wei; Brouwer, Kim L R

    2008-09-01

    Previous reports have indicated that in vitro biliary clearance (Cl(biliary)) determined in sandwich-cultured hepatocytes correlates well with in vivo Cl(biliary) for limited sets of compounds. This study was designed to estimate the in vitro Cl(biliary) in sandwich-cultured rat hepatocytes (SCRHs) of angiotensin II receptor blockers and HMG-CoA reductase inhibitors that undergo limited metabolism, to compare the estimated Cl(biliary) values with published in vivo Cl(biliary) data in rats, and to characterize the mechanism(s) of basolateral uptake and canalicular excretion of these drugs in rats. The average biliary excretion index (BEI) and in vitro Cl(biliary) values of olmesartan, valsartan, pravastatin, rosuvastatin, and pitavastatin were 15, 19, 43, 45, and 20%, respectively, and 1.7, 3.2, 4.4, 46.1, and 34.6 ml/min/kg, respectively. Cl(biliary) predicted from SCRHs, accounting for plasma unbound fraction, correlated with reported in vivo Cl(biliary) for these drugs. The rank order of Cl(biliary) values predicted from SCRHs was consistent with in vivo Cl(biliary) values. Bromosulfophthalein inhibited the uptake of all drugs. BEI and Cl(biliary) values of olmesartan, valsartan, pravastatin, and rosuvastatin, known multidrug resistance-associated protein (Mrp) 2 substrates, were reduced in SCRHs from Mrp2-deficient (TR(-)) compared with wild-type (WT) rats. Although Mrp2 plays a minor role in pitavastatin biliary excretion, pitavastatin BEI and Cl(biliary) were reduced in TR(-) compared with WT SCRHs; Bcrp expression in SCRHs from TR(-) rats was decreased. In conclusion, in vitro Cl(biliary) determined in SCRHs can be used to estimate and compare in vivo Cl(biliary) of compounds in rats and to characterize transport proteins responsible for their hepatic uptake and excretion. PMID:18574002

  15. 硝酸还原酶抑制剂钨酸钠对油菜硝态氮积累的影响%Effects of Nitrate Reductase Inhibitor Na2WO4 on Nitrate Accumulation in Oilseed Rape

    Institute of Scientific and Technical Information of China (English)

    杨荣; 邱炜红; 王朝辉; 王小英

    2012-01-01

    采用溶液培养方法,选取硝酸盐积累差异明显的两个油菜品种(低硝态氮积累品种‘红油3号’和高硝态氮积累品种‘中双6号’,研究苗期根系硝酸还原酶(NR)活性被抑制以后两个油菜品种叶片、叶柄和根系中NR活性和硝态氮含量的变化.结果表明:1.0 mmol·L-1的NR活性抑制剂Na2WO4对两个油菜品种的根系NR活性抑制效果最佳;根系NR活性被抑制以后,两个油菜品种的根系NR活性、硝态氮吸收速率均显著下降,而硝态氮含量却显著上升;且Na2WO4对‘中双6号’硝态氮吸收的抑制程度强于其对‘红油3号’的抑制.叶片和叶柄的NR活性变化不显著,但叶柄硝态氮含量显著下降,叶片硝态氮含量稳定,且这一趋势在低积累品种‘红油3号’中表现得更为明显.%A soilless culture (nutrient solution) experiment was conducted to study the effects of nitrate re-ductase inhibitor Na2WO4 on nitrate reductase (NR) activity and NO3"-N content in some organs (including root, leaf, petiole) of two different cultivars (high nitrate-N accumulation type 'Zhongshuang 6' and low nitrate-N accumulation type 'Hongyou 3') oilseed rape (Brassica napus L.) at seedling stage. Results showed that the most appropriate concentration of Na2WO4 was 1.0 mmol-L-1 Na2WO4 significantly decreased NR activity and NO3-N absorption rate in the root of oilseed rape comparing with the control (CK), however, significantly increasing in NO3-N content. High nitrate accumulation type 'Zhongshuang 6' had higher inhibiter efficiency comparing with low nitrate accumulation type 'Hongyou 3'. There were no significant difference on NR activity in leaf and petiole with or without Na2WO4, in contrast, Na2WO4 significantly decreased NO3 -N content in the petiole of oilseed rape, and NO3 -N content in the leaf was almost stable under it treatment, especially in 'Hongyou 3'.

  16. Active site fingerprinting and pharmacophore screening strategies for the identification of dual inhibitors of protein kinase C [Formula: see text] and poly (ADP-ribose) polymerase-1 (PARP-1).

    Science.gov (United States)

    Chadha, Navriti; Silakari, Om

    2016-08-01

    Current clinical studies have revealed that diabetic complications are multifactorial disorders that target two or more pathways. The majority of drugs in clinical trial target aldose reductase and protein kinase C ([Formula: see text]), while recent studies disclosed a significant role played by poly (ADP-ribose) polymerase-1 (PARP-1). In light of this, the current study was aimed to identify novel dual inhibitors of [Formula: see text] and PARP-1 using a pharmaco-informatics methodology. Pharmacophore-based 3D QSAR models for these two targets were generated using HypoGen and used to screen three commercially available chemical databases to identify dual inhibitors of [Formula: see text] and PARP-1. Overall, 18 hits were obtained from the screening process; the hits were filtered based on their drug-like properties and predicted binding affinities (docking analysis). Important amino acid residues were predicted by developing a fingerprint of the active site using alanine-scanning mutagenesis and molecular dynamics. The stability of the complexes (18 hits with both proteins) and their final binding orientations were investigated using molecular dynamics simulations. Thus, novel hits have been predicted to have good binding affinities for [Formula: see text] and PARP-1 proteins, which could be further investigated for in vitro/in vivo activity. PMID:27216445

  17. Increased resistance to 14 alpha-demethylase inhibitors (DMIs) in Aspergillus niger by coexpression of the Penicillium itulicum eburicol 14 alpha-demethylase (cyp51) and the A-niger cytochromeP450 reductase (cprA) genes

    NARCIS (Netherlands)

    Brink, van den J.M.; Nistelrooy, van J.G.M.; Waard, de M.A.; Hondel, van den C.A.M.J.J.; Gorcom, van R.F.M.

    1996-01-01

    In this paper we describe the effects of over-expression of the Penicillium italicum gene encoding eburicol 14α-demethylase (cyp51), in Aspergillus niger strains with one or multiple copies of the gene encoding cytochrome P450 reductase (cprA), on the eburicol 14α-demethylase activity. Eburicol 14α-

  18. Trypanothione Reductase: A Viable Chemotherapeutic Target for Antitrypanosomal and Antileishmanial Drug Design

    Directory of Open Access Journals (Sweden)

    M. Omar F. Khan

    2007-01-01

    Full Text Available Trypanosomiasis and leishmaniasis are two debilitating disease groups caused by parasites of Trypanosoma and Leishmania spp. and affecting millions of people worldwide. A brief outline of the potential targets for rational drug design against these diseases are presented, with an emphasis placed on the enzyme trypanothione reductase. Trypanothione reductase was identified as unique to parasites and proposed to be an effective target against trypanosomiasis and leishmaniasis. The biochemical basis of selecting this enzyme as a target, with reference to the simile and contrast to human analogous enzyme glutathione reductase, and the structural aspects of its active site are presented. The process of designing selective inhibitors for the enzyme trypanothione reductase has been discussed. An overview of the different chemical classes of inhibitors of trypanothione reductase with their inhibitory activities against the parasites and their prospects as future chemotherapeutic agents are briefl y revealed.

  19. Feed-forward control of prostate growth: dihydrotestosterone induces expression of its own biosynthetic enzyme, steroid 5 alpha-reductase.

    OpenAIRE

    George, F W; Russell, D.W.; Wilson, J. D.

    1991-01-01

    Dihydrotestosterone, the primary mediator of prostate growth, is synthesized in target tissues from the circulating androgen testosterone through the action of steroid 5 alpha-reductase (EC 1.3.99.5). The expression of 5 alpha-reductase and the level of 5 alpha-reductase messenger RNA in rat ventral prostate are regulated by androgens. To determine whether this control is mediated by dihydrotestosterone or testosterone, we investigated the effect of finasteride, a potent inhibitor of steroid ...

  20. Evaluation of 5α-reductase inhibitory activity of certain herbs useful as antiandrogens.

    Science.gov (United States)

    Nahata, A; Dixit, V K

    2014-08-01

    This study demonstrates 5α-reductase inhibitory activity of certain herbs useful in the management of androgenic disorders. Ganoderma lucidum (Curtis) P. Karst (GL), Urtica dioica Linn. (UD), Caesalpinia bonducella Fleming. (CB), Tribulus terrestris Linn. (TT), Pedalium murex Linn. (PM), Sphaeranthus indicus Linn. (SI), Cuscuta reflexa Roxb. (CR), Citrullus colocynthis Schrad. (CC), Benincasa hispida Cogn. (BH), Phyllanthus niruri Linn. (PN) and Echinops echinatus Linn. (EE) were included in the study. Petroleum ether, ethanol and aqueous extracts of these herbs were tested for their 5α-reductase inhibitory activity against the standard 5α-reductase inhibitor, finasteride. A biochemical method to determine the activity of 5α-reductase was used to evaluate the inhibition of different extracts to the enzyme. The optical density (OD) value of each sample was measured continuously with ultraviolet spectrophotometer for the reason that the substrate NADPH has a specific absorbance at 340 nm. As the enzyme 5α-reductase uses NADPH as a substrate, so in the presence of 5α-reductase inhibitor, the NADPH concentration will increase with the function of time. This method thus implicates the activity of 5α-reductase. The method proved to be extremely useful to screen the herbs for their 5α-reductase inhibitory potential. GL, UD, BH, SI and CR came out to be promising candidates for further exploring their antiandrogenic properties. PMID:23710567

  1. Asymmetric assembly of aldose carbohydrates from formaldehyde and glycolaldehyde by tandem biocatalytic aldol reactions.

    Science.gov (United States)

    Szekrenyi, Anna; Garrabou, Xavier; Parella, Teodor; Joglar, Jesús; Bujons, Jordi; Clapés, Pere

    2015-09-01

    The preparation of multifunctional chiral molecules can be greatly simplified by adopting a route via the sequential catalytic assembly of achiral building blocks. The catalytic aldol assembly of prebiotic compounds into stereodefined pentoses and hexoses is an as yet unmet challenge. Such a process would be of remarkable synthetic utility and highly significant with regard to the origin of life. Pursuing an expedient enzymatic approach, here we use engineered D-fructose-6-phosphate aldolase from Escherichia coli to prepare a series of three- to six-carbon aldoses by sequential one-pot additions of glycolaldehyde. Notably, the pertinent selection of the aldolase variant provides control of the sugar size. The stereochemical outcome of the addition was also altered to allow the synthesis of L-glucose and related derivatives. Such engineered biocatalysts may offer new routes for the straightforward synthesis of natural molecules and their analogues that circumvent the intricate enzymatic pathways forged by evolution. PMID:26291944

  2. Asymmetric assembly of aldose carbohydrates from formaldehyde and glycolaldehyde by tandem biocatalytic aldol reactions

    Science.gov (United States)

    Szekrenyi, Anna; Garrabou, Xavier; Parella, Teodor; Joglar, Jesús; Bujons, Jordi; Clapés, Pere

    2015-09-01

    The preparation of multifunctional chiral molecules can be greatly simplified by adopting a route via the sequential catalytic assembly of achiral building blocks. The catalytic aldol assembly of prebiotic compounds into stereodefined pentoses and hexoses is an as yet unmet challenge. Such a process would be of remarkable synthetic utility and highly significant with regard to the origin of life. Pursuing an expedient enzymatic approach, here we use engineered D-fructose-6-phosphate aldolase from Escherichia coli to prepare a series of three- to six-carbon aldoses by sequential one-pot additions of glycolaldehyde. Notably, the pertinent selection of the aldolase variant provides control of the sugar size. The stereochemical outcome of the addition was also altered to allow the synthesis of L-glucose and related derivatives. Such engineered biocatalysts may offer new routes for the straightforward synthesis of natural molecules and their analogues that circumvent the intricate enzymatic pathways forged by evolution.

  3. Equine 5α-reductase activity and expression in epididymis.

    Science.gov (United States)

    Corbin, C J; Legacki, E L; Ball, B A; Scoggin, K E; Stanley, S D; Conley, A J

    2016-10-01

    The 5α-reductase enzymes play an important role during male sexual differentiation, and in pregnant females, especially equine species where maintenance relies on 5α-reduced progesterone, 5α-dihydroprogesterone (DHP). Epididymis expresses 5α-reductases but was not studied elaborately in horses. Epididymis from younger and older postpubertal stallions was divided into caput, corpus and cauda and examined for 5α-reductase activity and expression of type 1 and 2 isoforms by quantitative real-time polymerase chain reaction (qPCR). Metabolism of progesterone and testosterone to DHP and dihydrotestosterone (DHT), respectively, by epididymal microsomal protein was examined by thin-layer chromatography and verified by liquid chromatography tandem mass spectrometry (LC-MS/MS). Relative inhibitory potencies of finasteride and dutasteride toward equine 5α-reductase activity were investigated. Pregnenolone was investigated as an additional potential substrate for 5α-reductase, suggested previously from in vivo studies in mares but never directly examined. No regional gradient of 5α-reductase expression was observed by either enzyme activity or transcript analysis. Results of PCR experiments suggested that type 1 isoform predominates in equine epididymis. Primers for the type 2 isoform were unable to amplify product from any samples examined. Progesterone and testosterone were readily reduced to DHP and DHT, and activity was effectively inhibited by both inhibitors. Using epididymis as an enzyme source, no experimental evidence was obtained supporting the notion that pregnenolone could be directly metabolized by equine 5α-reductases as has been suggested by previous investigators speculating on alternative metabolic pathways leading to DHP synthesis in placenta during equine pregnancies. PMID:27466384

  4. Molecular distribution and degradation status of combined aldoses in sinking particulate organic matter

    Science.gov (United States)

    Panagiotopoulos, C.; Sempéré, R.

    2003-04-01

    Particulate samples were collected by using floating sediment traps (50--300 m) and in situ pumps (30 and 200 m) in the Southern Indian Ocean (Polar Front Zone (PFZ) and Sub-Tropical Zone (STZ)), Mediterranean Sea (Ligurian and Ionian Seas) and Atlantic Ocean (Upwelling (UPW) of Agadir-Morocco). They were studied for monosaccharide composition after acid hydrolysis (HCl 0.09 M, 20 h, 100^oC) by using High Performance Anion Exchange Chromatography followed by Pulsed Amperometric Detection (HPAEC-PAD). Our results indicated that higher PCHO yields (calculated as PCHO-C/POC ratios) were associated to higher C:N ratios (Med. Sea sample, PCHO yields = 12.7 ± 7.7%; C:N ratios = 8.3 ± 1.6; n = 12) whether the opposite trend was found for Southern Ocean samples (PCHO yields = 3.3 ± 0.75%; C:N ratios = 5.7 ± 0.59, n = 5) indicating significant variability in the sugar content of particles which might be due to the degradation degree of the particles as well as to the initial chemical composition of plankton. Alternatively, other processes such as high production of extracellular polysaccharides (type transparent exopolymer polysaccharides (TEP)) due to phosphorus limitation of some phytoplanktonic species may increase the sugar content in Mediterranean particles and the C/N ratio. In any case, glucose appeared to be the most abundant monosaccharide in Mediterranean Sea or UPW samples (range 23--59 wt% of the total aldoses) whereas ribose (17--39 wt%) and galactose (range 10--28 wt%) were the predominant aldoses in Southern Indian Ocean. These sugars (glucose + ribose) exhibited a strong negative relationship with C:N (r = -0.53, p >0.01; n = 30) in sediment traps (data from this study) and sediment (data from literature) particulate material which further indicates that these two monosaccharides are selectively extracted from the carbohydrate pool in sediment. In vitro biodegradation experiments performed with large particles (>60 μm) sampled using in situ pumps in

  5. Bioactive constituents of Clausena lansium and a method for discrimination of aldose enantiomers.

    Science.gov (United States)

    Shen, De-Yang; Chao, Chih-Hua; Chan, Hsiu-Hui; Huang, Guan-Jhong; Hwang, Tsong-Long; Lai, Chin-Yu; Lee, Kuo-Hsiung; Thang, Tran Dinh; Wu, Tian-Shung

    2012-10-01

    Glycosides, clausenosides A and B, and carbazole alkaloids, clausenaline A, claulamine A, and claulamine B, together with 50 known compounds, were isolated from the stems of Clausena lansium. Their structures were determined by means of spectroscopic methods, including that of CD and 1D/2D NMR analysis. Claulamine A has a 1-oxygenated carbazole skeleton with a rare 2,3-lactone ring, and claulamine B represents an hitherto unknown acetal carbazole alkaloid. Thirty-one of the isolated known compounds were evaluated in various assays for anti-inflammatory activity. Among them, imperatorin, isoheraclenin, and osthol exhibited selective and potent inhibition of formyl-l-methionyl-l-leucyl-l-phenylalanine/cytochalasin B (fMLP/CB)-induced superoxide anion generation, and lansiumarin C also decreased nitric oxide (NO) and tumor necrosis factor-α (TNF-α) production in lipopolysaccharide (LPS)-induced macrophages. In addition, a modified HPLC method of pre-column derivatization was developed that is more practical for simultaneous analysis of aldose enantiomers as compared to the literature method. The absolute configurations of the sugar moieties in clausenosides A and B were determined with this modified method. PMID:22818357

  6. Genetics Home Reference: sepiapterin reductase deficiency

    Science.gov (United States)

    Skip to main content Your Guide to Understanding Genetic Conditions Enable Javascript for addthis links to activate. ... Conditions Genes Chromosomes & mtDNA Resources Help Me Understand Genetics Home Health Conditions sepiapterin reductase deficiency sepiapterin reductase ...

  7. Comparison of the xylose reductase-xylitol dehydrogenase and the xylose isomerase pathways for xylose fermentation by recombinant Saccharomyces cerevisiae

    Science.gov (United States)

    Karhumaa, Kaisa; Sanchez, Rosa Garcia; Hahn-Hägerdal, Bärbel; Gorwa-Grauslund, Marie-F

    2007-01-01

    Background Two heterologous pathways have been used to construct recombinant xylose-fermenting Saccharomyces cerevisiae strains: i) the xylose reductase (XR) and xylitol dehydrogenase (XDH) pathway and ii) the xylose isomerase (XI) pathway. In the present study, the Pichia stipitis XR-XDH pathway and the Piromyces XI pathway were compared in an isogenic strain background, using a laboratory host strain with genetic modifications known to improve xylose fermentation (overexpressed xylulokinase, overexpressed non-oxidative pentose phosphate pathway and deletion of the aldose reductase gene GRE3). The two isogenic strains and the industrial xylose-fermenting strain TMB 3400 were studied regarding their xylose fermentation capacity in defined mineral medium and in undetoxified lignocellulosic hydrolysate. Results In defined mineral medium, the xylose consumption rate, the specific ethanol productivity, and the final ethanol concentration were significantly higher in the XR- and XDH-carrying strain, whereas the highest ethanol yield was achieved with the strain carrying XI. While the laboratory strains only fermented a minor fraction of glucose in the undetoxified lignocellulose hydrolysate, the industrial strain TMB 3400 fermented nearly all the sugar available. Xylitol was formed by the XR-XDH-carrying strains only in mineral medium, whereas in lignocellulose hydrolysate no xylitol formation was detected. Conclusion Despite by-product formation, the XR-XDH xylose utilization pathway resulted in faster ethanol production than using the best presently reported XI pathway in the strain background investigated. The need for robust industrial yeast strains for fermentation of undetoxified spruce hydrolysates was also confirmed. PMID:17280608

  8. Essential fatty acids and their metabolites could function as endogenous HMG-CoA reductase and ACE enzyme inhibitors, anti-arrhythmic, anti-hypertensive, anti-atherosclerotic, anti-inflammatory, cytoprotective, and cardioprotective molecules

    Directory of Open Access Journals (Sweden)

    Das Undurti N

    2008-10-01

    Full Text Available Abstract Lowering plasma low density lipoprotein-cholesterol (LDL-C, blood pressure, homocysteine, and preventing platelet aggregation using a combination of a statin, three blood pressure lowering drugs such as a thiazide, a β blocker, and an angiotensin converting enzyme (ACE inhibitor each at half standard dose; folic acid; and aspirin-called as polypill- was estimated to reduce cardiovascular events by ~80%. Essential fatty acids (EFAs and their long-chain metabolites: γ-linolenic acid (GLA, dihomo-GLA (DGLA, arachidonic acid, eicosapentaenoic acid (EPA, and docosahexaenoic acid (DHA and other products such as prostaglandins E1 (PGE1, prostacyclin (PGI2, PGI3, lipoxins (LXs, resolvins, protectins including neuroprotectin D1 (NPD1 prevent platelet aggregation, lower blood pressure, have anti-arrhythmic action, reduce LDL-C, ameliorate the adverse actions of homocysteine, show anti-inflammatory actions, activate telomerase, and have cytoprotective properties. Thus, EFAs and their metabolites show all the classic actions expected of the "polypill". Unlike the proposed "polypill", EFAs are endogenous molecules present in almost all tissues, have no significant or few side effects, can be taken orally for long periods of time even by pregnant women, lactating mothers, and infants, children, and adults; and have been known to reduce the incidence cardiovascular diseases including stroke. In addition, various EFAs and their long-chain metabolites not only enhance nitric oxide generation but also react with nitric oxide to yield their respective nitroalkene derivatives that produce vascular relaxation, inhibit neutrophil degranulation and superoxide formation, inhibit platelet activation, and possess PPAR-γ ligand activity and release NO, thus prevent platelet aggregation, thrombus formation, atherosclerosis, and cardiovascular diseases. Based on these evidences, I propose that a rational combination of ω-3 and ω-6 fatty acids and the co

  9. REGULATION OF NITRATE REDUCTASE ACTIVITY IN RICE (ORYZA SATIVA L. BY GROWTH REGULATORS

    Directory of Open Access Journals (Sweden)

    S HEMALATHA

    2002-12-01

    Full Text Available The effect of three growth regulators, namely kinetin, 6 benzyl adenine, 2 chloro ethyl trimethyl ammonium chloride at three concentrations (10-6 M, 5 x 10-5 M 10-4 M was studied on the catalytic activity of nitrate reductase in green and etiolated seedlings. A concentration of 5 x 10-5 M was optimal for all the growth regulators treatments. All the growth regulators stimulated nitrate reductase activity effectively at 5 x 10-5M concentration in both etiolated and green seedlings and had an additive effect when supplemented by NO-3 up to 140% to 160%. The 99.2% and 93.4% inhibition of nitrate reductase activity resulted in development of etiolated and green seedlings, respectively when treated with eukaryotic 80S ribosome protein synthesis inhibitor cycloheximide. Prokaryotic 70S inhibitor chloromphenicol did not have any effect on measured parameters. Actinomycin D, a RNA synthesis inhibitor also inhibited the enzyme activity as 80s inhibitors (Green 80%, etiolated 98%. One may suggest from this that both DNA and protein synthesis are involved in the induction of nitrate reductase activity. The differential effect of aminoacids was observed on enzyme activity in combination with growth regulators.

  10. INHIBITION OF TYPE I 5α-REDUCTASE BY MEDICINAL PLANT EXTRACTS

    Directory of Open Access Journals (Sweden)

    Patil Vijaya

    2011-03-01

    Full Text Available Type I 5α-reductase has been implicated in skin disorders such as acne, hirsutism and male pattern baldness and its inhibition offers a potential treatment for these disorders. The aim of this study was to investigate the inhibition of type I 5α-reductase activity by extracts from Indian medicinal plants. Plant extracts were screened and selected based on their ability to inhibit Propionibacterium acnes and Staphylococcus epidermidis. Since type I 5α-reductase metabolises testosterone to Δ4-androstene-3, 17-dione, the activity of enzyme was determined using RIA for testosterone and Δ4-androstene-3, 17-dione. It was found that methanolic extract of Embelia ribes was a potent inhibitor of type I 5α-reductase (IC50:100μg/mL. Extracts of Vitex negundo, Terminalia chebula, and Terminalia bellerica which also inhibited type I 5α-reductase (IC50: 200-390 μg /mL. Therefore herbal formulation of these plant extracts may be used in the treatment of skin disorders involving type I 5α-reductase.

  11. Phosphoglycerate kinase acts in tumour angiogenesis as a disulphide reductase

    Science.gov (United States)

    Lay, Angelina J.; Jiang, Xing-Mai; Kisker, Oliver; Flynn, Evelyn; Underwood, Anne; Condron, Rosemary; Hogg, Philip J.

    2000-12-01

    Disulphide bonds in secreted proteins are considered to be inert because of the oxidizing nature of the extracellular milieu. An exception to this rule is a reductase secreted by tumour cells that reduces disulphide bonds in the serine proteinase plasmin. Reduction of plasmin initiates proteolytic cleavage in the kringle 5 domain and release of the tumour blood vessel inhibitor angiostatin. New blood vessel formation or angiogenesis is critical for tumour expansion and metastasis. Here we show that the plasmin reductase isolated from conditioned medium of fibrosarcoma cells is the glycolytic enzyme phosphoglycerate kinase. Recombinant phosphoglycerate kinase had the same specific activity as the fibrosarcoma-derived protein. Plasma of mice bearing fibrosarcoma tumours contained several-fold more phosphoglycerate kinase, as compared with mice without tumours. Administration of phosphoglycerate kinase to tumour-bearing mice caused an increase in plasma levels of angiostatin, and a decrease in tumour vascularity and rate of tumour growth. Our findings indicate that phosphoglycerate kinase not only functions in glycolysis but is secreted by tumour cells and participates in the angiogenic process as a disulphide reductase.

  12. MEK2 regulates ribonucleotide reductase activity through functional interaction with ribonucleotide reductase small subunit p53R2

    OpenAIRE

    Piao, Chunmei; Youn, Cha-Kyung; Jin, Min; Yoon, Sang Pil; Chang, In-Youb; Lee, Jung Hee; You, Ho Jin

    2012-01-01

    The p53R2 protein, a newly identified member of the ribonucleotide reductase family that provides nucleotides for DNA damage repair, is directly regulated by p53. We show that p53R2 is also regulated by a MEK2 (ERK kinase 2/MAP kinase kinase 2)-dependent pathway. Increased MEK1/2 phosphorylation by serum stimulation coincided with an increase in the RNR activity in U2OS and H1299 cells. The inhibition of MEK2 activity, either by treatment with a MEK inhibitor or by transfection with MEK2 siRN...

  13. Fatty acyl-CoA reductase

    Energy Technology Data Exchange (ETDEWEB)

    Reiser, Steven E.; Somerville, Chris R.

    1998-12-01

    The present invention relates to bacterial enzymes, in particular to an acyl-CoA reductase and a gene encoding an acyl-CoA reductase, the amino acid and nucleic acid sequences corresponding to the reductase polypeptide and gene, respectively, and to methods of obtaining such enzymes, amino acid sequences and nucleic acid sequences. The invention also relates to the use of such sequences to provide transgenic host cells capable of producing fatty alcohols and fatty aldehydes.

  14. Crystallographic investigation of the cooperative interaction between trimethoprim, reduced cofactor and dihydrofolate reductase

    International Nuclear Information System (INIS)

    The structure of the complex between E. coli form I dihydrofolate reductase, the antibacterial trimethoprim and NADPH has been determined by X-ray crystallography. The inhibitor and cofactor are in mutual contact. A flexible chain segment which includes Met 20 is in contact with the inhibitor in the presence of NADPH, but more distant in its absence. By contrast, the inhibitor conformation is little changed with NADPH present. The authors discuss these observations with regard to the mutually cooperative binding of these ligands to the protein, and to the associated enhancement of inhibitory selectivity shown by trimethoprim for bacterial as opposed to vertebrate enzyme. (Auth.)

  15. Discovery and characterization of a xylose reductase from Zymomonas mobilis ZM4.

    Science.gov (United States)

    Agrawal, Manoj; Chen, Rachel Ruizhen

    2011-11-01

    Formation of xylitol, a byproduct from xylose fermentation, is a major limiting factor in ethanol production from xylose in engineered Zymomonas strains, yet the postulated xylose reductase remains elusive. We report here the discovery of xylose reductase in Zymomonas mobilis and, for the first time, to associate the enzyme function with its gene. Besides xylose and xylulose, the enzyme was active towards benzaldehyde, furfural, 5-hydroxymethyl furfural, and acetaldehyde, exhibiting nearly 150-times higher affinity with benzaldehyde than xylose. The discovery of xylose reductase paves the way for further improvement of xylose fermentation in Z. mobilis. The enzyme may also be used to mitigate toxicity of furfural and other inhibitors from plant biomass. PMID:21720846

  16. HMGCoA-Reductase Inhibitors in Dementia: Benefit or Harm

    OpenAIRE

    Padala, Kalpana P.; Potter, Jane F.; Tsuneya Ikezu

    2009-01-01

    Dementia is a syndrome characterized by a decline in cognitive function. Alzheimer’s disease and cerebro-vascular disease are the most common causes of dementia. Many factors (genetic, life style, vascular etc.) appear to play some role in the development of dementia. Statins significantly reduce vascular disease and could reduce cognitive impairment in later life. Although most cross-sectional and longitudinal studies suggested a lower incidence of dementia in long-term statin users, randomi...

  17. Structure-Guided Development of Efficacious Antifungal Agents Targeting Candida Glabrata Dihydrofolate Reductase

    Energy Technology Data Exchange (ETDEWEB)

    Liu, J.; Bolstad, D; Smith, A; Priestley, N; Wright, D; Anderson, A

    2008-01-01

    Candida glabrata is a lethal fungal pathogen resistant to many antifungal agents and has emerged as a critical target for drug discovery. Over the past several years, we have been developing a class of propargyl-linked antifolates as antimicrobials and hypothesized that these compounds could be effective inhibitors of dihydrofolate reductase (DHFR) from C. glabrata. We initially screened a small collection of these inhibitors and found modest levels of potency. Subsequently, we determined the crystal structure of C. glabrata DHFR bound to a representative inhibitor with data to 1.6 A resolution. Using this structure, we designed and synthesized second-generation inhibitors. These inhibitors bind the C. glabrata DHFR enzyme with subnanomolar potency, display greater than 2000-fold levels of selectivity over the human enzyme, and inhibit the growth of C. glabrata at levels observed with clinically employed therapeutics.

  18. The Effect of 5α-reductase Inhibition with Finasteride and Dutasteride on Bone Mineral Density in Older Men with Benign Prostatic Hyperplasia

    OpenAIRE

    Radin Mačukat, Indira; Španjol, Josip; Crnčević Orlić, Željka; Žuvić Butorac, Marta; Marinović, Marin; Fučkar Ćupić, Dora

    2014-01-01

    Testosterone is converted to dihyrotestosterone by two isoenzymes of 5α-reductase. Finasteride and dutasteride are 5α-reductase inhibitors commonly used in the treatment of benign prostatic hyperplasia. We compared indices of bone mineral density in 50 men treated with finasteride, 50 men treated with dutasteride and 50 men as control. Bone mineral density of spine and hip were measured using dual energy X-ray absorptiometry. Bone formation was assessed by measuring serum osteocalcin and bone...

  19. Comparison of the xylose reductase-xylitol dehydrogenase and the xylose isomerase pathways for xylose fermentation by recombinant Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Hahn-Hägerdal Bärbel

    2007-02-01

    Full Text Available Abstract Background Two heterologous pathways have been used to construct recombinant xylose-fermenting Saccharomyces cerevisiae strains: i the xylose reductase (XR and xylitol dehydrogenase (XDH pathway and ii the xylose isomerase (XI pathway. In the present study, the Pichia stipitis XR-XDH pathway and the Piromyces XI pathway were compared in an isogenic strain background, using a laboratory host strain with genetic modifications known to improve xylose fermentation (overexpressed xylulokinase, overexpressed non-oxidative pentose phosphate pathway and deletion of the aldose reductase gene GRE3. The two isogenic strains and the industrial xylose-fermenting strain TMB 3400 were studied regarding their xylose fermentation capacity in defined mineral medium and in undetoxified lignocellulosic hydrolysate. Results In defined mineral medium, the xylose consumption rate, the specific ethanol productivity, and the final ethanol concentration were significantly higher in the XR- and XDH-carrying strain, whereas the highest ethanol yield was achieved with the strain carrying XI. While the laboratory strains only fermented a minor fraction of glucose in the undetoxified lignocellulose hydrolysate, the industrial strain TMB 3400 fermented nearly all the sugar available. Xylitol was formed by the XR-XDH-carrying strains only in mineral medium, whereas in lignocellulose hydrolysate no xylitol formation was detected. Conclusion Despite by-product formation, the XR-XDH xylose utilization pathway resulted in faster ethanol production than using the best presently reported XI pathway in the strain background investigated. The need for robust industrial yeast strains for fermentation of undetoxified spruce hydrolysates was also confirmed.

  20. Differential expression of 5-alpha reductase isozymes in the prostate and its clinical implications

    OpenAIRE

    Kai Wang; Dong-Dong Fan; Song Jin; Nian-Zeng Xing; Yi-Nong Niu

    2014-01-01

    The development of human benign or malignant prostatic diseases is closely associated with androgens, primarily testosterone (T) and dihydrotestosterone (DHT). T is converted to DHT by 5-alpha reductase (5-AR) isozymes. Differential expression of 5-AR isozymes is observed in both human benign and malignant prostatic tissues. 5-AR inhibitors (5-ARI) are commonly used for the treatment of benign prostatic hyperplasia (BPH) and were once promoted as chemopreventive agents for prostate cancer (PC...

  1. A Fluorimetric Readout Reporting the Kinetics of Nucleotide-Induced Human Ribonucleotide Reductase Oligomerization

    OpenAIRE

    Fu, Yuan; Lin, Hongyu; Wisitpitthaya, Somsinee; Blessing, William A.; Aye, Yimon

    2014-01-01

    Human ribonucleotide reductase (hRNR) is a target of nucleotide chemotherapeutics in clinical use. The nucleotide-induced oligomeric regulation of hRNR subunit α is increasingly being recognized as an innate and drug-relevant mechanism for enzyme activity modulation. In the presence of negative feedback inhibitor dATP and leukemia drug clofarabine nucleotides, hRNR-α assembles into catalytically inert hexameric complexes, whereas nucleotide effectors that govern substrate specificity typicall...

  2. Regulation of assimilatory nitrate reductase activity in soil by microbial assimilation of ammonium.

    OpenAIRE

    McCarty, G.W.; Bremner, J. M.

    1992-01-01

    It is well established that assimilatory nitrate reductase (ANR) activity in soil is inhibited by ammonium (NH4+). To elucidate the mechanism of this inhibition, we studied the effect of L-methionine sulfoximine (MSX), an inhibitor of NH4+ assimilation by microorganisms, on assimilatory reduction of nitrate (NO3-) in aerated soil slurries treated with NH4+. We found that NH4+ strongly inhibited ANR activity in these slurries and that MSX eliminated this inhibition. We also found that MSX indu...

  3. Changes in aortic endothelium ultrastructure in male rats following castration, replacement with testosterone and administration of 5α-reductase inhibitor%去势或用5α-还原酶抑制剂后雄性大鼠血管内皮超微结构改变的研究

    Institute of Scientific and Technical Information of China (English)

    Y. L. Lu; L. Kuang; H. Zhu; H. Wu; X. F. Wang; Y. P. Pang; N. J. Wang; D. L. Yu

    2007-01-01

    Aim: To investigate the relationship between low androgen level and ultrastructure of vascular endothelium. Methods:Forty-eight male Sprague-Dawley rats were randomly divided into four groups: group A, normal rats with sham castration; group B, castrated rats; group C, castrated rats given testosterone (T) undecanoate; and group D, intact rats treated with 5α-reductase inhibitor. After 10 weeks of treatment or castration, rats in different groups were killed and serum T, free T (FT) and dihydrotestosterone (DHT) were measured. The aortic endothelia were scanned under electron microcopy and the Vascular Endothelium Structure Score (VESS) was computed. Results: Serum T and FT concentrations of rats in group B were significantly lower than those of the other three groups (P < 0.01);DHT concentrations of group D rats were significantly decreased (P < 0.01) when compared with those of groups A and C. Rats in groups B and D rats (with low androgen levels) had obvious damage to their endothelial surfaces,which appeared crimpled, rough, adhesive and ruptured, and had high destruction of VESS. Conclusion: These results suggest that low concentrations of T and DHT are associated with ultrastructural damage of the aortic endothelia in male rats.%目的:研究低雄性激素水平对雄性大鼠血管内皮超微结构改变的影响.方法:将48只雄性SD大鼠随机分成四组:A组为正常大鼠作为对照组,B组为雄性大鼠去势组,C组为去势后用十一酸睾酮(T)替代治疗大鼠组,D组为正常大鼠用5α-还原酶抑制剂治疗组,每组均为12只大鼠.10周后用放射免疫法测定血清睾酮,游离睾酮(Free Testosterone,FT)和双氢睾酮(Dihydrotestosterone,DHT)水平,用扫描电镜观察大鼠腹主动脉内皮的超微结构并给予血管内皮结构评分(VESS).结果:B组的血清睾酮和游离睾酮的水平与A、C、D组相比较有显著地降低(P<0.01);D组的双氢睾酮水平与A组和C组比较显著地降低(P<0.01);

  4. Identification, Characterization, and Classification of Genes Encoding Perchlorate Reductase

    OpenAIRE

    Bender, Kelly S.; Shang, Ching; Chakraborty, Romy; Belchik, Sara M.; Coates, John D.; Achenbach, Laurie A.

    2005-01-01

    The reduction of perchlorate to chlorite, the first enzymatic step in the bacterial reduction of perchlorate, is catalyzed by perchlorate reductase. The genes encoding perchlorate reductase (pcrABCD) in two Dechloromonas species were characterized. Sequence analysis of the pcrAB gene products revealed similarity to α- and β-subunits of microbial nitrate reductase, selenate reductase, dimethyl sulfide dehydrogenase, ethylbenzene dehydrogenase, and chlorate reductase, all of which are type II m...

  5. Sepiapterin Reductase Deficiency: Mimic of Cerebral Palsy

    OpenAIRE

    J Gordon Millichap

    2012-01-01

    Researchers at University of California at San Diego, and 22 other US national and international centers studied the clinical, biochemical, and molecular findings in a cohort of 38 patients with sepiapterin reductase deficiency (SRD).

  6. Dual-5α-reductase inhibition promotes hepatic lipid accumulation in man.

    OpenAIRE

    Hazlehurst, JM; Oprescu, AI; N. Nikolaou; Di Guida, R; Grinbergs, AEK; Davies, NP; Flintham, RB; Armstrong, MJ; Taylor, AE; Hughes, BA; Yu, J.; Hodson, L.; Dunn, WB; Tomlinson, JW

    2016-01-01

    5α-Reductase 1 and 2 (SRD5A1, SRD5A2) inactivate cortisol to 5α-dihydrocortisol in addition to their role in the generation of DHT. Dutasteride (dual SRD5A1 and SRD5A2 inhibitor) and finasteride (selective SRD5A2 inhibitor) are commonly prescribed, but their potential metabolic effects have only recently been identified.Our objective was to provide a detailed assessment of the metabolic effects of SRD5A inhibition and in particular the impact on hepatic lipid metabolism.We conducted a randomi...

  7. Binding of Natural and Synthetic Polyphenols to Human Dihydrofolate Reductase

    Directory of Open Access Journals (Sweden)

    José Neptuno Rodríguez-López

    2009-12-01

    Full Text Available Dihydrofolate reductase (DHFR is the subject of intensive investigation since it appears to be the primary target enzyme for antifolate drugs. Fluorescence quenching experiments show that the ester bond-containing tea polyphenols (--epigallocatechin gallate (EGCG and (--epicatechin gallate (ECG are potent inhibitors of DHFR with dissociation constants (KD of 0.9 and 1.8 μM, respectively, while polyphenols lacking the ester bound gallate moiety [e.g., (--epigallocatechin (EGC and (--epicatechin (EC] did not bind to this enzyme. To avoid stability and bioavailability problems associated with tea catechins we synthesized a methylated derivative of ECG (3-O-(3,4,5-trimethoxybenzoyl-(--epicatechin; TMECG, which effectively binds to DHFR (KD = 2.1 μM. In alkaline solution, TMECG generates a stable quinone methide product that strongly binds to the enzyme with a KD of 8.2 nM. Quercetin glucuronides also bind to DHFR but its effective binding was highly dependent of the sugar residue, with quercetin-3-xyloside being the stronger inhibitor of the enzyme with a KD of 0.6 μM. The finding that natural polyphenols are good inhibitors of human DHFR could explain the epidemiological data on their prophylactic effects for certain forms of cancer and open a possibility for the use of natural and synthetic polyphenols in cancer chemotherapy.

  8. [Diabetic cataract and flavonoids (first results) (author's transl)].

    Science.gov (United States)

    Leuenberger, P M

    1978-04-01

    The possible effects of Quercetine, a potent inhibitor of aldose-reductase, on cataract formation and vascular permeability were investigated in streptozotocine-diabetic rats. Preliminary results after peroral administration of Quercetine did not allow to demonstrate a clear inhibitory effect on cataract formation. PMID:418268

  9. Drug: D02323 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available (ATC) classification [BR:br08303] A ALIMENTARY TRACT AND METABOLISM A10 DRUGS USED IN DIABETES... A10X OTHER DRUGS USED IN DIABETES A10XA Aldose reductase inhibitors A10XA01 Tolrestat D02323 T

  10. BIOLOGICAL ROLE OF ALDO-KETO REDUCTASES IN RETINOIC ACID BIOSYNTHESIS AND SIGNALING

    Directory of Open Access Journals (Sweden)

    F. Xavier eRuiz

    2012-04-01

    Full Text Available Several aldo-keto reductase (AKR enzymes from subfamilies 1B and 1C show retinaldehyde reductase activity, having low Km and kcat values. Only AKR1B10 and 1B12, with all-trans-retinaldehyde, and AKR1C3, with 9-cis-retinaldehyde, display high catalytic efficiency. Major structural determinants for retinaldehyde isomer specificity are located in the external loops (A and C for AKR1B10, and B for AKR1C3, as assessed by site-directed mutagenesis and molecular dynamics. Cellular models have shown that AKR1B and 1C enzymes are well suited to work in vivo as retinaldehyde reductases and to regulate retinoic acid (RA biosynthesis at hormone pre-receptor level. An additional physiological role for the retinaldehyde reductase activity of these enzymes, consistent with their tissue localization, is their participation in β-carotene absorption. Retinaldehyde metabolism may be subjected to subcellular compartmentalization, based on enzyme localization. While retinaldehyde oxidation to RA takes place in the cytosol, reduction to retinol could take place in the cytosol by AKRs or in the membranes of endoplasmic reticulum by microsomal retinaldehyde reductases. Upregulation of some AKR1 enzymes in different cancer types may be linked to their induction by oxidative stress and to their participation in different signaling pathways related to cell proliferation. AKR1B10 and AKR1C3, through their retinaldehyde reductase activity, trigger a decrease in the RA biosynthesis flow, resulting in RA deprivation and consequently lower differentiation, with an increased cancer risk in target tissues. Rational design of selective AKR inhibitors could lead to development of novel drugs for cancer treatment as well as reduction of chemotherapeutic drug resistance.

  11. Structure of a bacterial homologue of vitamin K epoxide reductase

    Energy Technology Data Exchange (ETDEWEB)

    Li, Weikai; Schulman, Sol; Dutton, Rachel J.; Boyd, Dana; Beckwith, Jon; Rapoport, Tom A. (Harvard-Med); (HHMI)

    2010-03-19

    Vitamin K epoxide reductase (VKOR) generates vitamin K hydroquinone to sustain {gamma}-carboxylation of many blood coagulation factors. Here, we report the 3.6 {angstrom} crystal structure of a bacterial homologue of VKOR from Synechococcus sp. The structure shows VKOR in complex with its naturally fused redox partner, a thioredoxin-like domain, and corresponds to an arrested state of electron transfer. The catalytic core of VKOR is a four transmembrane helix bundle that surrounds a quinone, connected through an additional transmembrane segment with the periplasmic thioredoxin-like domain. We propose a pathway for how VKOR uses electrons from cysteines of newly synthesized proteins to reduce a quinone, a mechanism confirmed by in vitro reconstitution of vitamin K-dependent disulphide bridge formation. Our results have implications for the mechanism of the mammalian VKOR and explain how mutations can cause resistance to the VKOR inhibitor warfarin, the most commonly used oral anticoagulant.

  12. Thioredoxin and Its Reductase Are Present on Synaptic Vesicles, and Their Inhibition Prevents the Paralysis Induced by Botulinum Neurotoxins

    Directory of Open Access Journals (Sweden)

    Marco Pirazzini

    2014-09-01

    Full Text Available Botulinum neurotoxins consist of a metalloprotease linked via a conserved interchain disulfide bond to a heavy chain responsible for neurospecific binding and translocation of the enzymatic domain in the nerve terminal cytosol. The metalloprotease activity is enabled upon disulfide reduction and causes neuroparalysis by cleaving the SNARE proteins. Here, we show that the thioredoxin reductase-thioredoxin protein disulfide-reducing system is present on synaptic vesicles and that it is functional and responsible for the reduction of the interchain disulfide of botulinum neurotoxin serotypes A, C, and E. Specific inhibitors of thioredoxin reductase or thioredoxin prevent intoxication of cultured neurons in a dose-dependent manner and are also very effective inhibitors of the paralysis of the neuromuscular junction. We found that this group of inhibitors of botulinum neurotoxins is very effective in vivo. Most of them are nontoxic and are good candidates as preventive and therapeutic drugs for human botulism.

  13. Alteration of organic matter during infaunal polychaete gut passage and links to sediment organic geochemistry. Part II: Fatty acids and aldoses

    Science.gov (United States)

    Woulds, Clare; Middelburg, Jack J.; Cowie, Greg L.

    2014-07-01

    The activities of sediment-dwelling fauna are known to influence the rates of and pathways through which organic matter is cycled in marine sediments, and thus to influence eventual organic carbon burial or decay. However, due to methodological constraints, the role of faunal gut passage in determining the subsequent composition and thus degradability of organic matter is relatively little studied. Previous studies of organic matter digestion by benthic fauna have been unable to detect uptake and retention of specific biochemicals in faunal tissues, and have been of durations too short to fit digestion into the context of longer-term sedimentary degradation processes. Therefore this study aimed to investigate the aldose and fatty acid compositional alterations occurring to organic matter during gut passage by the abundant and ubiquitous polychaetes Hediste diversicolor and Arenicola marina, and to link these to longer-term changes typically observed during organic matter decay. This aim was approached through microcosm experiments in which selected polychaetes were fed with 13C-labelled algal detritus, and organisms, sediments, and faecal pellets were sampled at three timepoints over ∼6 weeks. Samples were analysed for their 13C-labelled aldose and fatty acid contents using GC-MS and GC-IRMS. Compound-selective net accumulation of biochemicals in polychaete tissues was observed for both aldoses and fatty acids, and the patterns of this were taxon-specific. The dominant patterns included an overall loss of glucose and polyunsaturated fatty acids; and preferential preservation or production of arabinose, microbial compounds (rhamnose, fucose and microbial fatty acids), and animal-synthesised fatty acids. These patterns may have been driven by fatty acid essentiality, preferential metabolism of glucose, and A. marina grazing on bacteria. Fatty acid suites in sediments from faunated microcosms showed greater proportions of saturated fatty acids and bacterial markers

  14. Structural and mechanistic insights on nitrate reductases.

    Science.gov (United States)

    Coelho, Catarina; Romão, Maria João

    2015-12-01

    Nitrate reductases (NR) belong to the DMSO reductase family of Mo-containing enzymes and perform key roles in the metabolism of the nitrogen cycle, reducing nitrate to nitrite. Due to variable cell location, structure and function, they have been divided into periplasmic (Nap), cytoplasmic, and membrane-bound (Nar) nitrate reductases. The first crystal structure obtained for a NR was that of the monomeric NapA from Desulfovibrio desulfuricans in 1999. Since then several new crystal structures were solved providing novel insights that led to the revision of the commonly accepted reaction mechanism for periplasmic nitrate reductases. The two crystal structures available for the NarGHI protein are from the same organism (Escherichia coli) and the combination with electrochemical and spectroscopic studies also lead to the proposal of a reaction mechanism for this group of enzymes. Here we present an overview on the current advances in structural and functional aspects of bacterial nitrate reductases, focusing on the mechanistic implications drawn from the crystallographic data. PMID:26362109

  15. 5α-Reductase Type 2 Regulates Glucocorticoid Action and Metabolic Phenotype in Human Hepatocytes.

    Science.gov (United States)

    Nasiri, Maryam; Nikolaou, Nikolaos; Parajes, Silvia; Krone, Nils P; Valsamakis, George; Mastorakos, George; Hughes, Beverly; Taylor, Angela; Bujalska, Iwona J; Gathercole, Laura L; Tomlinson, Jeremy W

    2015-08-01

    Glucocorticoids and androgens have both been implicated in the pathogenesis of nonalcoholic fatty liver disease (NAFLD); androgen deficiency in males, androgen excess in females, and glucocorticoid excess in both sexes are associated with NAFLD. Glucocorticoid and androgen action are regulated at a prereceptor level by the enzyme 5α-reductase type 2 (SRD5A2), which inactivates glucocorticoids to their dihydrometabolites and converts T to DHT. We have therefore explored the role of androgens and glucocorticoids and their metabolism by SRD5A2 upon lipid homeostasis in human hepatocytes. In both primary human hepatocytes and human hepatoma cell lines, glucocorticoids decreased de novo lipogenesis in a dose-dependent manner. Whereas androgen treatment (T and DHT) increased lipogenesis in cell lines and in primary cultures of human hepatocytes from female donors, it was without effect in primary hepatocyte cultures from men. SRD5A2 overexpression reduced the effects of cortisol to suppress lipogenesis and this effect was lost following transfection with an inactive mutant construct. Conversely, pharmacological inhibition using the 5α-reductase inhibitors finasteride and dutasteride augmented cortisol action. We have demonstrated that manipulation of SRD5A2 activity can regulate lipogenesis in human hepatocytes in vitro. This may have significant clinical implications for those patients prescribed 5α-reductase inhibitors, in particular augmenting the actions of glucocorticoids to modulate hepatic lipid flux. PMID:25974403

  16. Respiratory arsenate reductase as a bidirectional enzyme

    International Nuclear Information System (INIS)

    The haloalkaliphilic bacterium Alkalilimnicola ehrlichii is capable of anaerobic chemolithoautotrophic growth by coupling the oxidation of arsenite (As(III)) to the reduction of nitrate and carbon dioxide. Analysis of its complete genome indicates that it lacks a conventional arsenite oxidase (Aox), but instead possesses two operons that each encode a putative respiratory arsenate reductase (Arr). Here we show that one homolog is expressed under chemolithoautotrophic conditions and exhibits both arsenite oxidase and arsenate reductase activity. We also demonstrate that Arr from two arsenate respiring bacteria, Alkaliphilus oremlandii and Shewanella sp. strain ANA-3, is also biochemically reversible. Thus Arr can function as a reductase or oxidase. Its physiological role in a specific organism, however, may depend on the electron potentials of the molybdenum center and [Fe-S] clusters, additional subunits, or constitution of the electron transfer chain. This versatility further underscores the ubiquity and antiquity of microbial arsenic metabolism.

  17. Respiratory arsenate reductase as a bidirectional enzyme

    Science.gov (United States)

    Richey, C.; Chovanec, P.; Hoeft, S.E.; Oremland, R.S.; Basu, P.; Stolz, J.F.

    2009-01-01

    The haloalkaliphilic bacterium Alkalilimnicola ehrlichii is capable of anaerobic chemolithoautotrophic growth by coupling the oxidation of arsenite (As(III)) to the reduction of nitrate and carbon dioxide. Analysis of its complete genome indicates that it lacks a conventional arsenite oxidase (Aox), but instead possesses two operons that each encode a putative respiratory arsenate reductase (Arr). Here we show that one homolog is expressed under chemolithoautotrophic conditions and exhibits both arsenite oxidase and arsenate reductase activity. We also demonstrate that Arr from two arsenate respiring bacteria, Alkaliphilus oremlandii and Shewanella sp. strain ANA-3, is also biochemically reversible. Thus Arr can function as a reductase or oxidase. Its physiological role in a specific organism, however, may depend on the electron potentials of the molybdenum center and [Fe–S] clusters, additional subunits, or constitution of the electron transfer chain. This versatility further underscores the ubiquity and antiquity of microbial arsenic metabolism.

  18. 5alpha-reductase: history and clinical importance.

    Science.gov (United States)

    Marks, Leonard S

    2004-01-01

    The treatment of men with symptomatic benign prostatic hyperplasia (BPH) has shifted dramatically from surgery to drug therapy over the past decade. The revolution in BPH treatment began with the discovery of congenital 5alpha-reductase (5AR) deficiency, leading to the appreciation of 2 different androgenic hormones: testosterone, which mediates overt masculinization in the adult male, and dihydrotestosterone (DHT), which mediates prostatic growth, acne, facial beard, and male pattern baldness. Inhibition of DHT in adults results in prostatic shrinkage and symptomatic relief in many men, without the side effects seen with conventional androgen-deprivation therapy. The 5AR inhibitor drugs (finasteride and the dual inhibitor, dutasteride) are able to ablate the accumulation of intraprostatic DHT, the mechanism most responsible for prostate growth and maintenance. Not only may these drugs relieve symptoms, but they may also alter the natural history of the BPH process. Future indications for the 5ARI drugs could include chemoprevention of prostate cancer, prophylaxis of BPH-related complications, and treatment of BPH-associated hematuria. PMID:16985920

  19. Loss of quinone reductase 2 function selectively facilitates learning behaviors.

    Science.gov (United States)

    Benoit, Charles-Etienne; Bastianetto, Stephane; Brouillette, Jonathan; Tse, YiuChung; Boutin, Jean A; Delagrange, Philippe; Wong, TakPan; Sarret, Philippe; Quirion, Rémi

    2010-09-22

    High levels of reactive oxygen species (ROS) are associated with deficits in learning and memory with age as well as in Alzheimer's disease. Using DNA microarray, we demonstrated the overexpression of quinone reductase 2 (QR2) in the hippocampus in two models of learning deficits, namely the aged memory impaired rats and the scopolamine-induced amnesia model. QR2 is a cytosolic flavoprotein that catalyzes the reduction of its substrate and enhances the production of damaging activated quinone and ROS. QR2-like immunostaining is enriched in cerebral structures associated with learning behaviors, such as the hippocampal formation and the temporofrontal cortex of rat, mouse, and human brains. In cultured rat embryonic hippocampal neurons, selective inhibitors of QR2, namely S26695 and S29434, protected against menadione-induced cell death by reversing its proapoptotic action. S26695 (8 mg/kg) also significantly inhibited scopolamine-induced amnesia. Interestingly, adult QR2 knock-out mice demonstrated enhanced learning abilities in various tasks, including Morris water maze, object recognition, and rotarod performance test. Other behaviors related to anxiety (elevated plus maze), depression (forced swim), and schizophrenia (prepulse inhibition) were not affected in QR2-deficient mice. Together, these data suggest a role for QR2 in cognitive behaviors with QR2 inhibitors possibly representing a novel therapeutic strategy toward the treatment of learning deficits especially observed in the aged brain. PMID:20861374

  20. 21 CFR 864.7375 - Glutathione reductase assay.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Glutathione reductase assay. 864.7375 Section 864... reductase assay. (a) Identification. A glutathione reductase assay is a device used to determine the... fluorescence and photometry. The results of this assay are used in the diagnosis of liver disease,...

  1. Characterization of the chlorate reductase from Pseudomonas chloritidismutans

    NARCIS (Netherlands)

    Wolterink, A.F.W.M.; Schiltz, E.; Hagedoorn, P.L.; Hagen, W.R.; Kengen, S.W.M.; Stams, A.J.M.

    2003-01-01

    A chlorate reductase has been purified from the chlorate-reducing strain Pseudomonas chloritidismutans. Comparison with the periplasmic (per)chlorate reductase of strain GR-1 showed that the cytoplasmic chlorate reductase of P. chloritidismutans reduced only chlorate and bromate. Differences were al

  2. HMG-CoA reductase inhibitory activity and phytocomponent investigation of Basella alba leaf extract as a treatment for hypercholesterolemia

    Directory of Open Access Journals (Sweden)

    Baskaran G

    2015-01-01

    Full Text Available Gunasekaran Baskaran,1 Shamala Salvamani,1 Siti Aqlima Ahmad,1 Noor Azmi Shaharuddin,1 Parveen Devi Pattiram,2 Mohd Yunus Shukor1 1Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, 2Department of Food Technology, Faculty of Food Science and Technology, Universiti Putra Malaysia, Selangor, Malaysia Abstract: The enzyme 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA reductase is the key enzyme of the mevalonate pathway that produces cholesterol. Inhibition of HMG-CoA reductase reduces cholesterol biosynthesis in the liver. Synthetic drugs, statins, are commonly used for the treatment of hypercholesterolemia. Due to the side effects of statins, natural HMG-CoA reductase inhibitors of plant origin are needed. In this study, 25 medicinal plant methanol extracts were screened for anti-HMG-CoA reductase activity. Basella alba leaf extract showed the highest inhibitory effect at about 74%. Thus, B. alba was examined in order to investigate its phytochemical components. Gas chromatography with tandem mass spectrometry and reversed phase high-performance liquid chromatography analysis revealed the presence of phenol 2,6-bis(1,1-dimethylethyl, 1-heptatriacotanol, oleic acid, eicosyl ester, naringin, apigenin, luteolin, ascorbic acid, and a-tocopherol, which have been reported to possess antihypercholesterolemic effects. Further investigation of in vivo models should be performed in order to confirm its potential as an alternative treatment for hypercholesterolemia and related cardiovascular diseases. Keywords: HMG-CoA reductase, Basella alba, phytochemical, GC-MS/MS, RP-HPLC, hypercholesterolemia

  3. 5α-reductase inhibition suppresses testosterone-induced initial regrowth of regressed xenograft prostate tumors in animal models.

    Science.gov (United States)

    Masoodi, Khalid Z; Ramos Garcia, Raquel; Pascal, Laura E; Wang, Yujuan; Ma, Hei M; O'Malley, Katherine; Eisermann, Kurtis; Shevrin, Daniel H; Nguyen, Holly M; Vessella, Robert L; Nelson, Joel B; Parikh, Rahul A; Wang, Zhou

    2013-07-01

    Androgen deprivation therapy (ADT) is the standard treatment for patients with prostate-specific antigen progression after treatment for localized prostate cancer. An alternative to continuous ADT is intermittent ADT (IADT), which allows recovery of testosterone during off-cycles to stimulate regrowth and differentiation of the regressed prostate tumor. IADT offers patients a reduction in side effects associated with ADT, improved quality of life, and reduced cost with no difference in overall survival. Our previous studies showed that IADT coupled with 5α-reductase inhibitor (5ARI), which blocks testosterone conversion to DHT could prolong survival of animals bearing androgen-sensitive prostate tumors when off-cycle duration was fixed. To further investigate this clinically relevant observation, we measured the time course of testosterone-induced regrowth of regressed LuCaP35 and LNCaP xenograft tumors in the presence or absence of a 5ARI. 5α-Reductase inhibitors suppressed the initial regrowth of regressed prostate tumors. However, tumors resumed growth and were no longer responsive to 5α-reductase inhibition several days after testosterone replacement. This finding was substantiated by bromodeoxyuridine and Ki67 staining of LuCaP35 tumors, which showed inhibition of prostate tumor cell proliferation by 5ARI on day 2, but not day 14, after testosterone replacement. 5α-Reductase inhibitors also suppressed testosterone-stimulated proliferation of LNCaP cells precultured in androgen-free media, suggesting that blocking testosterone conversion to DHT can inhibit prostate tumor cell proliferation via an intracrine mechanism. These results suggest that short off-cycle coupled with 5α-reductase inhibition could maximize suppression of prostate tumor growth and, thus, improve potential survival benefit achieved in combination with IADT. PMID:23671262

  4. Induction and inhibition of NAD(P)H: quinone reductase in murine and human skin.

    Science.gov (United States)

    Merk, H; Jugert, F; Bonnekoh, B; Mahrle, G

    1991-01-01

    The purpose of this study was to characterize the human cutaneous NAD(P)H: quinone reductase (NQR) activity by known inhibitors of different reductases and to compare it with the murine skin and liver NQR activity. This enzyme plays a major role in the defence of cells against oxygen stress because it inhibits the 1-electron reduction of quinones to semiquinones and their subsequent oxidation to quinones termed as quinone redox cycle. It belongs to the aromatic hydrocarbon-responsive (Ah) battery. This gene battery includes Cyp1a1 (cytochrome P-450 IA1), Cyp1a2 (cytochrome P-450 IA2) and Nmo-1 [NAD(P)H: quinone reductase]. In the skin cytochrome P-450 IA1-dependent activity is about 1-5% compared to the corresponding activity in the liver, whereas NQR has the same activity in skin and liver. NQR was determined in the cytoplasm of murine skin, liver, and human keratinocytes using 2,6-dichlorophenolindophenol as the substrate. The Ah-receptor binding compounds, such as coal tar constituents, or 3-methylcholanthrene induce cytochrome P-450-dependent activities such as aryl hydrocarbon hydroxylase or 7-ethoxyresorufin-O-de-ethylase and NQR, whereas butyl hydroxytoluol, which does not bind to the Ah receptor, induces only NQR. For inhibition studies several known inhibitors of dihydrodiol dehydrogenase, aldo-keto and carbonyl reductase activities were used. There was a similar pattern of inhibition of the basal and induced activity in all tissues investigated. Pyrazole, progesterone and phenobarbital did not inhibit, whereas dicoumarol, rutin and indomethacin inhibited NQR activity in murine skin and liver as well as in human keratinocytes.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1768430

  5. Identification of a 4-Deoxy-l-erythro-5-hexoseulose Uronic Acid Reductase, FlRed, in an Alginolytic Bacterium Flavobacterium sp. Strain UMI-01

    Directory of Open Access Journals (Sweden)

    Akira Inoue

    2015-01-01

    Full Text Available In alginate-assimilating bacteria, alginate is depolymerized to unsaturated monosaccharide by the actions of endolytic and exolytic alginate lyases (EC 4.2.2.3 and EC 4.2.2.11. The monosaccharide is non-enzymatically converted to 4-deoxy-l-ery thro-5-hexoseulose uronic acid (DEH, then reduced to 2-keto-3-deoxy-d-gluconate (KDG by a specific reductase, and metabolized through the Entner–Doudoroff pathway. Recently, the NADPH-dependent reductase A1-R that belongs to short-chain dehydrogenases/reductases (SDR superfamily was identified as the DEH-reductase in Sphingomonas sp. A1. We have subsequently noticed that an SDR-like enzyme gene, flred, occurred in the genome of an alginolytic bacterium Flavobacterium sp. strain UMI-01. In the present study, we report on the deduced amino-acid sequence of flred and DEH-reducing activity of recombinant FlRed. The deduced amino-acid sequence of flred comprised 254 residues and showed 34% amino-acid identities to that of A1-R from Sphingomonas sp. A1 and 80%–88% to those of SDR-like enzymes from several alginolytic bacteria. Common sequence motifs of SDR-superfamily enzymes, e.g., the catalytic tetrad Asn-Lys-Tyr-Ser and the cofactor-binding sequence Thr-Gly-x-x-x-Gly-x-Gly in Rossmann fold, were completely conserved in FlRed. On the other hand, an Arg residue that determined the NADPH-specificity of Sphingomonas A1-R was replaced by Glu in FlRed. Thus, we investigated cofactor-preference of FlRed using a recombinant enzyme. As a result, the recombinant FlRed (recFlRed was found to show high specificity to NADH. recFlRed exhibited practically no activity toward variety of aldehyde, ketone, keto ester, keto acid and aldose substrates except for DEH. On the basis of these results, we conclude that FlRed is the NADH-dependent DEH-specific SDR of Flavobacterium sp. strain UMI-01.

  6. Nitrate reductase regulation in tomato roots by exogenous nitrate: a possible role in tolerance to long-term root anoxia

    OpenAIRE

    Allègre, Adeline; Silvestre, Jérôme; Morard, Philippe; Kallerhoff, Jean; Pinelli, Eric

    2004-01-01

    The mechanism of nitrate reductase (NR) regulation under long-term anoxia in roots of whole plants and the putative role of nitrate in anoxia tolerance have been addressed. NR activity in tomato roots increased significantly after 24 h of anaerobiosis and increased further by 48 h, with a concomitant release of nitrite into the culture medium. Anoxia promoted NR activation through dissociation of the 14-3-3 protein inhibitor and NR dephosphorylation. After 24 h of anoxia, the total amount of ...

  7. Steady-state pharmacokinetics of oral testosterone undecanoate with concomitant inhibition of 5α-reductase by finasteride

    OpenAIRE

    Roth, M. Y.; Dudley, R. E.; Hull, L; Leung, A; Christenson, P.; Wang, C; Swerdloff, R.; Amory, J. K.

    2010-01-01

    Oral testosterone undecanoate (TU) is used to treat testosterone deficiency; however, oral TU treatment elevates dihydrotestosterone (DHT), which may be associated with an increased risk of acne, male pattern baldness and prostate hyperplasia. Co-administration of 5α-reductase inhibitors with other formulations of oral testosterone suppresses DHT production and increases serum testosterone. We hypothesized that finasteride would increase serum testosterone and lower DHT during treatment with ...

  8. Inhibition of NADH-ubiquinone reductase activity by N,N'-dicyclohexylcarbodiimide and correlation of this inhibition with the occurrence of energy-coupling site 1 in various organisms

    International Nuclear Information System (INIS)

    The NADH-ubiquinone reductase activity of the respiratory chains of several organisms was inhibited by the carboxyl-modifying reagent N,N'-dicyclohexylcarbodiimide (DCCD). This inhibition correlated with the presence of an energy-transducing site in this segment of the respiratory chain. Where the NADH-quinone reductase segment involved an energy-coupling site (e.g., in bovine heart and rat liver mitochondria, and in Paracoccus denitrificans, Escherichia coli, and Thermus thermophilus HB-8 membranes), DCCD acted as an inhibitor of ubiquinone reduction by NADH. By contrast, where energy-coupling site 1 was absent (e.g., in Saccharomyces cerevisiae mitochondria and BacilLus subtilis membranes), there was no inhibition of NADH-ubiquinone reductase activity by DCCD. In the bovine and P. denitrificans systems, DCCD inhibition was pseudo first order with respect to incubation time, and reaction order with respect to inhibitor concentration was close to unity, indicating that inhibition resulted from the binding of one inhibitor molecule per active unit of NADH-ubiquinone reductase. In the bovine NADH-ubiquinone reductase complex (complex I), [14C]DCCD was preferentially incorporated into two subunits of molecular weight 49,000 and 29,000. The time course of labeling of the 29,000 molecular weight subunit with [14C]DCCD paralleled the time course of inhibition of NADH-ubiquinone reductase activity

  9. Differential expression of 5-alpha reductase isozymes in the prostate and its clinical implications

    Directory of Open Access Journals (Sweden)

    Kai Wang

    2014-04-01

    Full Text Available The development of human benign or malignant prostatic diseases is closely associated with androgens, primarily testosterone (T and dihydrotestosterone (DHT. T is converted to DHT by 5-alpha reductase (5-AR isozymes. Differential expression of 5-AR isozymes is observed in both human benign and malignant prostatic tissues. 5-AR inhibitors (5-ARI are commonly used for the treatment of benign prostatic hyperplasia (BPH and were once promoted as chemopreventive agents for prostate cancer (PCa. This review discusses the role of the differential expression of 5-AR in the normal development of the human prostate and in the pathogenesis and progression of BPH and PCa.

  10. Anti-HMG-CoA Reductase, Antioxidant, and Anti-Inflammatory Activities of Amaranthus viridis Leaf Extract as a Potential Treatment for Hypercholesterolemia

    Directory of Open Access Journals (Sweden)

    Shamala Salvamani

    2016-01-01

    Full Text Available Inflammation and oxidative stress are believed to contribute to the pathology of several chronic diseases including hypercholesterolemia (elevated levels of cholesterol in blood and atherosclerosis. HMG-CoA reductase inhibitors of plant origin are needed as synthetic drugs, such as statins, which are known to cause adverse effects on the liver and muscles. Amaranthus viridis (A. viridis has been used from ancient times for its supposedly medically beneficial properties. In the current study, different parts of A. viridis (leaf, stem, and seed were evaluated for potential anti-HMG-CoA reductase, antioxidant, and anti-inflammatory activities. The putative HMG-CoA reductase inhibitory activity of A. viridis extracts at different concentrations was determined spectrophotometrically by NADPH oxidation, using HMG-CoA as substrate. A. viridis leaf extract revealed the highest HMG-CoA reductase inhibitory effect at about 71%, with noncompetitive inhibition in Lineweaver-Burk plot analysis. The leaf extract showed good inhibition of hydroperoxides, 2,2-diphenyl-1-picrylhydrazyl (DPPH, nitric oxide (NO, and ferric ion radicals in various concentrations. A. viridis leaf extract was proven to be an effective inhibitor of hyaluronidase, lipoxygenase, and xanthine oxidase enzymes. The experimental data suggest that A. viridis leaf extract is a source of potent antioxidant and anti-inflammatory agent and may modulate cholesterol metabolism by inhibition of HMG-CoA reductase.

  11. Anti-HMG-CoA Reductase, Antioxidant, and Anti-Inflammatory Activities of Amaranthus viridis Leaf Extract as a Potential Treatment for Hypercholesterolemia.

    Science.gov (United States)

    Salvamani, Shamala; Gunasekaran, Baskaran; Shukor, Mohd Yunus; Shaharuddin, Noor Azmi; Sabullah, Mohd Khalizan; Ahmad, Siti Aqlima

    2016-01-01

    Inflammation and oxidative stress are believed to contribute to the pathology of several chronic diseases including hypercholesterolemia (elevated levels of cholesterol in blood) and atherosclerosis. HMG-CoA reductase inhibitors of plant origin are needed as synthetic drugs, such as statins, which are known to cause adverse effects on the liver and muscles. Amaranthus viridis (A. viridis) has been used from ancient times for its supposedly medically beneficial properties. In the current study, different parts of A. viridis (leaf, stem, and seed) were evaluated for potential anti-HMG-CoA reductase, antioxidant, and anti-inflammatory activities. The putative HMG-CoA reductase inhibitory activity of A. viridis extracts at different concentrations was determined spectrophotometrically by NADPH oxidation, using HMG-CoA as substrate. A. viridis leaf extract revealed the highest HMG-CoA reductase inhibitory effect at about 71%, with noncompetitive inhibition in Lineweaver-Burk plot analysis. The leaf extract showed good inhibition of hydroperoxides, 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO), and ferric ion radicals in various concentrations. A. viridis leaf extract was proven to be an effective inhibitor of hyaluronidase, lipoxygenase, and xanthine oxidase enzymes. The experimental data suggest that A. viridis leaf extract is a source of potent antioxidant and anti-inflammatory agent and may modulate cholesterol metabolism by inhibition of HMG-CoA reductase. PMID:27051453

  12. Anti-HMG-CoA Reductase, Antioxidant, and Anti-Inflammatory Activities of Amaranthus viridis Leaf Extract as a Potential Treatment for Hypercholesterolemia

    Science.gov (United States)

    Salvamani, Shamala; Gunasekaran, Baskaran; Shukor, Mohd Yunus; Shaharuddin, Noor Azmi; Sabullah, Mohd Khalizan

    2016-01-01

    Inflammation and oxidative stress are believed to contribute to the pathology of several chronic diseases including hypercholesterolemia (elevated levels of cholesterol in blood) and atherosclerosis. HMG-CoA reductase inhibitors of plant origin are needed as synthetic drugs, such as statins, which are known to cause adverse effects on the liver and muscles. Amaranthus viridis (A. viridis) has been used from ancient times for its supposedly medically beneficial properties. In the current study, different parts of A. viridis (leaf, stem, and seed) were evaluated for potential anti-HMG-CoA reductase, antioxidant, and anti-inflammatory activities. The putative HMG-CoA reductase inhibitory activity of A. viridis extracts at different concentrations was determined spectrophotometrically by NADPH oxidation, using HMG-CoA as substrate. A. viridis leaf extract revealed the highest HMG-CoA reductase inhibitory effect at about 71%, with noncompetitive inhibition in Lineweaver-Burk plot analysis. The leaf extract showed good inhibition of hydroperoxides, 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO), and ferric ion radicals in various concentrations. A. viridis leaf extract was proven to be an effective inhibitor of hyaluronidase, lipoxygenase, and xanthine oxidase enzymes. The experimental data suggest that A. viridis leaf extract is a source of potent antioxidant and anti-inflammatory agent and may modulate cholesterol metabolism by inhibition of HMG-CoA reductase. PMID:27051453

  13. Targeting 5α-reductase for prostate cancer prevention and treatment.

    Science.gov (United States)

    Nacusi, Lucas P; Tindall, Donald J

    2011-07-01

    Testosterone is the most abundant circulating androgen, and can be converted to dihydrotestosterone (DHT), a more potent androgen, by the 5α-reductase enzymes in target tissues. Current treatments for prostate cancer consist of reducing androgen levels by chemical or surgical castration or pure antiandrogen therapy that directly targets the androgen receptor (AR). Although these therapies reduce tumor burden and AR activity, the cancer inevitably recurs within 18-30 months. An approach targeting the androgen-AR axis at different levels could, therefore, improve the efficacy of prostate cancer therapy. Inhibition of 5α-reductase is one such approach; however, the two largest trials to investigate the use of the 5α-reductase inhibitors (5ARIs) finasteride and dutasteride in patients with prostate cancer have shown that, although the incidence of cancer was reduced by 5ARI treatment, those cancers that were detected were more aggressive than in patients treated with placebo. Thus, the best practice for using these drugs to prevent and treat prostate cancer remains unclear. PMID:21629218

  14. Berberine inhibits androgen synthesis by interaction with aldo-keto reductase 1C3 in 22Rv1 prostate cancer cells.

    Science.gov (United States)

    Tian, Yuantong; Zhao, Lijing; Wang, Ye; Zhang, Haitao; Xu, Duo; Zhao, Xuejian; Li, Yi; Li, Jing

    2016-01-01

    Aldo-keto reductase family 1 member C3 has recently been regarded as a potential therapeutic target in castrate-resistant prostate cancer. Herein, we investigated whether berberine delayed the progression of castrate-resistant prostate cancer by reducing androgen synthesis through the inhibition of Aldo-keto reductase family 1 member C3. Cell viability and cellular testosterone content were measured in prostate cancer cells. Aldo-keto reductase family 1 member C3 mRNA and protein level were detected by RT-PCR and Western bolt analyses, respectively. Computer analysis with AutoDock Tools explored the molecular interaction of berberine with Aldo-keto reductase family 1 member C3. We found that berberine inhibited 22Rv1 cells proliferation and decreased cellular testosterone formation in a dose-dependent manner. Berberine inhibited Aldo-keto reductase family 1 member C3 enzyme activity, rather than influenced mRNA and protein expressions. Molecular docking study demonstrated that berberine could enter the active center of Aldo-keto reductase family 1 member C3 and form p-p interaction with the amino-acid residue Phe306 and Phe311. In conclusion, the structural interaction of berberine with Aldo-keto reductase family 1 member C3 is attributed to the suppression of Aldo-keto reductase family 1 member C3 enzyme activity and the inhibition of 22Rv1 prostate cancer cell growth by decreasing the intracellular androgen synthesis. Our result provides the experimental basis for the design, research, and development of AKR1C3 inhibitors using berberine as the lead compound. PMID:26698234

  15. Regulation and degradation of HMGCo-A reductase.

    Science.gov (United States)

    Panda, T; Devi, V Amutha

    2004-12-01

    The enzyme, 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) controls the biosynthesis of cholesterol. Hypercholesterolemia and atherosclerosis are critical health risk factors. One way of controlling these risk factors is to manipulate regulation as well as degradation of HMGR. At present, a class of compounds called statins, which are HMGR inhibitors, are used for the treatment of hypercholesterolemia. However, statins suffer major setbacks as their use produces more adverse reactions than the desirable one of inhibiting the enzyme. Genetically engineered forms of HMGR are also studied in primitive life forms like bacteria, but detailed investigation of this enzyme in human systems is certainly required. Extensive studies have been made on the regulatory aspects of this enzyme, but no breakthrough is conspicuous in the clinical background to find an alternative treatment for hypercholesterolemia. The immediate need is to find an alternate way of regulating degradation of the enzyme. This review presents the importance of regulation and degradation of the HMGR enzyme in different systems to gain possible insight into alternative schemes for regulating this enzyme and, if these exist, the feasibility of extending them same to studies in mammalian systems. A high degree of similarity exists between mammalian and yeast HMGR. Detailed studies reported on the regulation and degradation of the yeast enzyme also throw more light on the mammalian system, leading to a better understanding of ways of controlling hypercholesterolemia. PMID:15558272

  16. Ribonucleotide reductase and cancer: biological mechanisms and targeted therapies.

    Science.gov (United States)

    Aye, Y; Li, M; Long, M J C; Weiss, R S

    2015-04-16

    Accurate DNA replication and repair is essential for proper development, growth and tumor-free survival in all multicellular organisms. A key requirement for the maintenance of genomic integrity is the availability of adequate and balanced pools of deoxyribonucleoside triphosphates (dNTPs), the building blocks of DNA. Notably, dNTP pool alterations lead to genomic instability and have been linked to multiple human diseases, including mitochondrial disorders, susceptibility to viral infection and cancer. In this review, we discuss how a key regulator of dNTP biosynthesis in mammals, the enzyme ribonucleotide reductase (RNR), impacts cancer susceptibility and serves as a target for anti-cancer therapies. Because RNR-regulated dNTP production can influence DNA replication fidelity while also supporting genome-protecting DNA repair, RNR has complex and stage-specific roles in carcinogenesis. Nevertheless, cancer cells are dependent on RNR for de novo dNTP biosynthesis. Therefore, elevated RNR expression is a characteristic of many cancers, and an array of mechanistically distinct RNR inhibitors serve as effective agents for cancer treatment. The dNTP metabolism machinery, including RNR, has been exploited for therapeutic benefit for decades and remains an important target for cancer drug development. PMID:24909171

  17. Characterization of the chlorate reductase from Pseudomonas chloritidismutans

    OpenAIRE

    Wolterink, A.F.W.M.; Schiltz, E; Hagedoorn, P.L.; Hagen, W.R.; Kengen, S.W.M.; Stams, A.J.M.

    2003-01-01

    A chlorate reductase has been purified from the chlorate-reducing strain Pseudomonas chloritidismutans. Comparison with the periplasmic (per)chlorate reductase of strain GR-1 showed that the cytoplasmic chlorate reductase of P. chloritidismutans reduced only chlorate and bromate. Differences were also found in N-terminal sequences, molecular weight, and subunit composition. Metal analysis and electron paramagnetic resonance measurements showed the presence of iron and molybdenum, which are al...

  18. Characterization of the Chlorate Reductase from Pseudomonas chloritidismutans

    OpenAIRE

    2003-01-01

    A chlorate reductase has been purified from the chlorate-reducing strain Pseudomonas chloritidismutans. Comparison with the periplasmic (per)chlorate reductase of strain GR-1 showed that the cytoplasmic chlorate reductase of P. chloritidismutans reduced only chlorate and bromate. Differences were also found in N-terminal sequences, molecular weight, and subunit composition. Metal analysis and electron paramagnetic resonance measurements showed the presence of iron and molybdenum, which are al...

  19. HMG-CoA reductase inhibitory activity and phytocomponent investigation of Basella alba leaf extract as a treatment for hypercholesterolemia.

    Science.gov (United States)

    Baskaran, Gunasekaran; Salvamani, Shamala; Ahmad, Siti Aqlima; Shaharuddin, Noor Azmi; Pattiram, Parveen Devi; Shukor, Mohd Yunus

    2015-01-01

    The enzyme 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase is the key enzyme of the mevalonate pathway that produces cholesterol. Inhibition of HMG-CoA reductase reduces cholesterol biosynthesis in the liver. Synthetic drugs, statins, are commonly used for the treatment of hypercholesterolemia. Due to the side effects of statins, natural HMG-CoA reductase inhibitors of plant origin are needed. In this study, 25 medicinal plant methanol extracts were screened for anti-HMG-CoA reductase activity. Basella alba leaf extract showed the highest inhibitory effect at about 74%. Thus, B. alba was examined in order to investigate its phytochemical components. Gas chromatography with tandem mass spectrometry and reversed phase high-performance liquid chromatography analysis revealed the presence of phenol 2,6-bis(1,1-dimethylethyl), 1-heptatriacotanol, oleic acid, eicosyl ester, naringin, apigenin, luteolin, ascorbic acid, and α-tocopherol, which have been reported to possess antihypercholesterolemic effects. Further investigation of in vivo models should be performed in order to confirm its potential as an alternative treatment for hypercholesterolemia and related cardiovascular diseases. PMID:25609924

  20. Mechanistic studies with solubilized rat liver steroid 5 alpha-reductase: Elucidation of the kinetic mechanism

    International Nuclear Information System (INIS)

    A solubilized preparation of steroid 5 alpha-reductase from rat liver has been used in studies focused toward an understanding of the kinetic mechanism associated with enzyme catalysis. From the results of analyses with product and dead-end inhibitors, a preferentially ordered binding of substrates and release of products from the surface of the enzyme is proposed. The observations from these experiments were identical with those using the steroid 5 alpha-reductase activity associated with rat liver microsomes. The primary isotope effects on steady-state kinetic parameters when [4S-2H]NADPH was used also were consistent with an ordered kinetic mechanism. Normal isotope effects were observed for all three kinetic parameters (Vm/Km for both testosterone and NADPH and Vm) at all substrate concentrations used experimentally. Upon extrapolation to infinite concentration of testosterone, the isotope effect on Vm/Km for NADPH approached unity, indicating that the nicotinamide dinucleotide phosphate is the first substrate binding to and the second product released from the enzyme. The isotope effects on Vm/Km for testosterone at infinite concentration of cofactor and on Vm were 3.8 +/- 0.5 and 3.3 +/- 0.4, respectively. Data from the pH profiles of these three steady-state parameters and the inhibition constants (1/Ki) of competitive inhibitors versus both substrates indicate that the binding of nicotinamide dinucleotide phosphate involves coordination of its anionic 2'-phosphate to a protonated enzyme-associated base with an apparent pK near 8.0. From these results, relative limits have been placed on several of the internal rate constants used to describe the ordered mechanism of the rat liver steroid 5 alpha-reductase

  1. Structure and mechanism of dimethylsulfoxide reductase, a molybdopterin-containing enzyme of DMSO reductase family

    International Nuclear Information System (INIS)

    Full text: Apart from nitrogenase, enzymes containing molybdenum are members of a superfamily, the molybdopterin-containing enzymes. Most of these enzymes catalyse an oxygen atom transfer and two electron transfer reaction. During catalysis the Mo at the active site cycles between the Mo(VI) and Mo(IV) states. The DMSO reductase family of molybdopterin-containing enzymes all contain a bis(molybdopterin guanine dinucleotide)Mo cofactor and over thirty examples have now been described. Over the last five years crystal structures of dimethylsulfoxide (DMSO) reductase and four other enzymes of the DMSO reductase family have revealed that enzymes of this family have a similar tertiary structure. The Mo atom at the active site is coordinated by four thiolate ligands provided by the dithiolene side chains of the two MGD molecules of the bis(MGD)Mo cofactor as well as a ligand provided by an amino acid side chain. In addition, an oxygen atom in the form of an oxo, hydroxo or aqua group is also coordinated to the Mo atom. In the case of dimethylsulfoxide reductase X-ray crystallography of the product-reduced species and Raman spectroscopy has demonstrated that the enzyme contains a single exchangeable oxo group that is H-bonded to W116

  2. Structure and function of NADPH-cytochrome P450 reductase and nitric oxide synthase reductase domain

    International Nuclear Information System (INIS)

    NADPH-cytochrome P450 reductase (CPR) and the nitric oxide synthase (NOS) reductase domains are members of the FAD-FMN family of proteins. The FAD accepts two reducing equivalents from NADPH (dehydrogenase flavin) and FMN acts as a one-electron carrier (flavodoxin-type flavin) for the transfer from NADPH to the heme protein, in which the FMNH ·/FMNH2 couple donates electrons to cytochrome P450 at constant oxidation-reduction potential. Although the interflavin electron transfer between FAD and FMN is not strictly regulated in CPR, electron transfer is activated in neuronal NOS reductase domain upon binding calmodulin (CaM), in which the CaM-bound activated form can function by a similar mechanism to that of CPR. The oxygenated form and spin state of substrate-bound cytochrome P450 in perfused rat liver are also discussed in terms of stepwise one-electron transfer from CPR. This review provides a historical perspective of the microsomal mixed-function oxidases including CPR and P450. In addition, a new model for the redox-linked conformational changes during the catalytic cycle for both CPR and NOS reductase domain is also discussed

  3. Glutathione Reductase of Vacuole. Comparison of Glutathione Reductase Activity of Vacuole and Tissue Extract of Red Beet Root (Beta vulgaris L.

    Directory of Open Access Journals (Sweden)

    E.V. Pradedova

    2016-02-01

    Full Text Available Glutathione reductase (GR, EC 1.8.1.7 is the enzyme that reduces oxidized glutathione (GSSG and thus regulates the redox state of glutathione (GSH/GSSG. GR has been studied in most plants. This enzyme has been identified in chloroplasts and cytosol, so these cellular compartments are considered to be the main place of the enzyme localization. In the same time, just a little is known about GR vacuoles. There are no conclusive evidences to prove the presence or absence of this enzyme in the vacuoles. GR activity was found in the vacuoles of red beet root cells (Beta vulgaris L.. The level of activity, the optimum pH and isoenzyme composition of GR were compared in the vacuoles and tissue extract of beet root. Vacuolar GR activity was quite high, it was 1.5-2 times higher than the activity of the tissue extract. Enzyme pH optimum of all the objects were identical. pH-optimum depend on the pyridine nucleotide nature: pH 7.0-8.0 was an optimal range with NADPH; pH 5.0 – with NADH. GR activity of the vacuoles and tissue extracts decreased in the presence of a noncompetitive inhibitor 1-chloro-2.4-dinitrobenzene (CDNB, indicating the specificity of this enzymatic reaction. Two bands with glutathione reductase activity have been identified in the vacuoles and tissue extracts using zymography method to determine the enzymatic activity in PAAG after electrophoresis of proteins. Belonging to the GR isoforms of these bands was confirmed by enzyme immunoassay (Western blotting. The electric mobility of isoforms of the study objects did not differ significantly. It is concluded that the biochemical characteristics of vacuolar glutathione reductase were substantially identical to the biochemical characteristics of other localization GR.

  4. Genetic identification of a respiratory arsenate reductase

    OpenAIRE

    Saltikov, Chad W.; Newman, Dianne K.

    2003-01-01

    For more than a decade, it has been recognized that arsenate [H2AsO41-; As(V)] can be used by microorganisms as a terminal electron acceptor in anaerobic respiration. Given the toxicity of arsenic, the mechanistic basis of this process is intriguing, as is its evolutionary origin. Here we show that a two-gene cluster (arrAB; arsenate respiratory reduction) in the bacterium Shewanella sp. strain ANA-3 specifically confers respiratory As(V) reductase activity. Mutants with in-frame deletions of...

  5. Membrane-associated chromate reductase activity from Enterobacter cloacae.

    OpenAIRE

    P. C. Wang; Mori, T.; Toda, K.; Ohtake, H

    1990-01-01

    Washed cells of Enterobacter cloacae HO1 reduced hexavalent chromium (chromate: CrO4(2-) anaerobically. Chromate reductase activity was preferentially associated with the membrane fraction of the cells. Right-side-out membrane vesicles prepared from E. cloacae cells showed high chromate reductase activities when ascorbate-reduced phenazine methosulfate was added as an electron donor.

  6. Canopy and seasonal profiles of nitrate reductase in soybeans

    Energy Technology Data Exchange (ETDEWEB)

    Harper, J.E.; Hageman, R.H.

    1972-01-01

    Nitrate reductase activity of soybeans (Glycine max L. Merr.) was evaluated in soil plots and outdoor hydroponic gravel culture systems throughout the growing season. Nitrate reductase profiles within the plant canopy were also established. Mean activity per gram fresh weight per hour of the entire plant canopy was highest in the seedling stage while total activity (activity per gram fresh weight per hour times the total leaf weight) reached a maximum when plants were in the full bloom to midpod fill stage. Nitrate reductase activity per gram fresh weight per hour was highest in the uppermost leaf just prior to full expansion and declined with leaf positions lower in the canopy. Total nitrate reductase activity per leaf was also highest in the uppermost fully expanded leaf during early growth stages. Maximum total activity shifted to leaf positions lower in the plant canopy with later growth stages. Nitrate reductase activity of soybeans grown in hydroponic systems was significantly higher than activity of adjacent soil grown plants at later growth stages, which suggested that under normal field conditions the potential for nitrate utilization may not be realized. Nitrate reductase activity per gram fresh weight per hour and nitrate content were positively correlated over the growing season with plants grown in either soil or solution culture. Computations based upon the nitrate reductase assay of plants grown in hydroponics indicated that from 1.7 to 1.8 grams N could have been supplied to the plant via the nitrate reductase process. 11 references, 9 figures, 3 tables.

  7. A novel assay revealed that ribonucleotide reductase is functionally important for interstrand DNA crosslink repair.

    Science.gov (United States)

    Fujii, Naoaki; Evison, Benjamin J; Actis, Marcelo L; Inoue, Akira

    2015-11-01

    Cells have evolved complex biochemical pathways for DNA interstrand crosslink (ICL) removal. Despite the chemotherapeutic importance of ICL repair, there have been few attempts to identify which mechanistic DNA repair inhibitor actually inhibits ICL repair. To identify such compounds, a new and robust ICL repair assay was developed using a novel plasmid that contains synthetic ICLs between a CMV promoter region that drives transcription and a luciferase reporter gene, and an SV40 origin of replication and the large T antigen (LgT) gene that enables self-replication in mammalian cells. In a screen against compounds that are classified as inhibitors of DNA repair or synthesis, the reporter generation was exquisitely sensitive to ribonucleotide reductase (RNR) inhibitors such as gemcitabine and clofarabine, but not to inhibitors of PARP, ATR, ATM, Chk1, and others. The effect was observed also by siRNA downregulation of RNR. Moreover, the reporter generation was also particularly sensitive to 3-AP, a non-nucleoside RNR inhibitor, but not significantly sensitive to DNA replication stressors, suggesting that the involvement of RNR in ICL repair is independent of incorporation of a nucleotide RNR inhibitor into DNA to induce replication stress. The reporter generation from a modified version of the plasmid that lacks the LgT-SV40ori motif was also adversely affected by RNR inhibitors, further indicating a role for RNR in ICL repair that is independent of DNA replication. Intriguingly, unhooking of cisplatin-ICL from nuclear DNA was significantly inhibited by low doses of gemcitabine, suggesting an unidentified functional role for RNR in the process of ICL unhooking. The assay approach could identify other molecules essential for ICLR in quantitative and flexible manner. PMID:26462050

  8. Intracellular signal transduction of PBAN action in the silkworm, Bombyx mori: involvement of acyl CoA reductase.

    Science.gov (United States)

    Ozawa, R; Matsumoto, S

    1996-03-01

    In the silkworm, Bombyx mori, production of the sex pheromone bombykol is regulated by a neurohormone termed PBAN. We have detected the activity of acyl CoA reductase in the pheromone gland of B. mori by using palmitoyl CoA as a substrate. The acyl CoA reductase requires NADPH, but not NADH, as a proton dono. When the pheromone gland was incubated with the PBAN fragment peptide TKYFSPRLamide, palmitoyl CoA was incorporated and converted into the corresponding C16 alcohols. Radio HPLC analysis revealed that these C16 alcohols were hexadecan-1-ol (81.2%), (Z)-11-hexadecen-1-ol (12.3%), and (E, Z)-10, 12-hexadecadien-1-ol (= bombykol, 6.5%). The production of C16 alcohols in the pheromone gland was inhibited by the known bombykol biosynthesis inhibitors EDTA, LaCl3, W-7, trifluoperazine, p-nitrophenyl phosphate, NaF and compactin. By contrast, when the pheromone gland homogenate was incubated in the presence of palmitoyl CoA and NADPH, production of C16 alcohols was affected by compactin, W-7 and trifluoperazine, but not by EDTA, LaCl3, p-nitrophenyl phosphate and NaF. These results indicate that compactin, W-7 and trifluoperazine directly suppress the step catalyzed by acyl CoA reductase, whereas EDTA, LaCl3, pNPP, and NaF inhibit bombykol production by affecting other biochemical steps in the signal transduction of PBAN action. The present results also imply that PBAN regulates the step catalyzed by acyl CoA reductase and that palmitoyl CoA could be used as a substrate of the acyl CoA reductase that regulates bombykol biosynthesis. PMID:8900596

  9. Corrosion inhibitors

    International Nuclear Information System (INIS)

    In this paper, we briefly describe the characteristics, cost and electrochemical nature of the corrosion phenomena as well as some of the technologies that are currently employed to minimize its effect. The main subject of the paper however, deals with the description, classification and mechanism of protection of the so-called corrosion inhibitors. Examples of the use of these substances in different aggressive environments are also presented as means to show that these compounds, or their combination, can in fact be used as excellent and relatively cheap technologies to control the corrosion of some metals. In the last part of the paper, the most commonly used techniques to evaluate the efficiency and performance of corrosion inhibitors are presented as well as some criteria to make a careful and proper selection of a corrosion inhibitor technology in a given situation. (Author) 151 refs

  10. In vitro effects of folate inhibitors on Toxoplasma gondii.

    OpenAIRE

    Derouin, F.; Chastang, C

    1989-01-01

    Three sulfonamides and four dihydrofolate reductase inhibitors were tested alone and in combination to determine their in vitro effects on two strains of Toxoplasma gondii grown in MRC5 fibroblast tissue culture. Toxoplasma growth was quantitated by an enzyme immunoassay performed directly on the fixed cultures, and linear regression models were used to quantify the relationship between the optical density values generated by the enzyme-linked immunosorbent assay and the concentrations of the...

  11. Structure and expression of human dihydropteridine reductase

    International Nuclear Information System (INIS)

    Dihydropteridine reductase catalyzes the NADH-mediated reduction of quinonoid dihydrobiopterin and is an essential component of the pterindependent aromatic amino acid hydroxylating systems. A cDNA for human DHPR was isolated from a human liver cDNA library in the vector λgt11 using a monospecific antibody against sheep DHPR. The nucleic acid sequence and amino acid sequence of human DHPR were determined from a full-length clone. A 112 amino acid sequence of sheep DHPR was obtained by sequencing purified sheep DHPR. This sequence is highly homologous to the predicted amino acid sequence of the human protein. Gene transfer of the recombinant human DHPR into COS cells leads to expression of DHPR enzymatic activity. These results indicate that the cDNA clone identified by antibody screening is an authentic and full-length cDNA for human DHPR

  12. Nitrite Reductase Activity in Engineered Azurin Variants.

    Science.gov (United States)

    Berry, Steven M; Strange, Jacob N; Bladholm, Erika L; Khatiwada, Balabhadra; Hedstrom, Christine G; Sauer, Alexandra M

    2016-05-01

    Nitrite reductase (NiR) activity was examined in a series of dicopper P.a. azurin variants in which a surface binding copper site was added through site-directed mutagenesis. Four variants were synthesized with copper binding motifs inspired by the catalytic type 2 copper binding sites found in the native noncoupled dinuclear copper enzymes nitrite reductase and peptidylglycine α-hydroxylating monooxygenase. The four azurin variants, denoted Az-NiR, Az-NiR3His, Az-PHM, and Az-PHM3His, maintained the azurin electron transfer copper center, with the second designed copper site located over 13 Å away and consisting of mutations Asn10His,Gln14Asp,Asn16His-azurin, Asn10His,Gln14His,Asn16His-azurin, Gln8Met,Gln14His,Asn16His-azurin, and Gln8His,Gln14His,Asn16His-azurin, respectively. UV-visible absorption spectroscopy, EPR spectroscopy, and electrochemistry of the sites demonstrate copper binding as well as interaction with small exogenous ligands. The nitrite reduction activity of the variants was determined, including the catalytic Michaelis-Menten parameters. The variants showed activity (0.34-0.59 min(-1)) that was slower than that of native NiRs but comparable to that of other model systems. There were small variations in activity of the four variants that correlated with the number of histidines in the added copper site. Catalysis was found to be reversible, with nitrite produced from NO. Reactions starting with reduced azurin variants demonstrated that electrons from both copper centers were used to reduce nitrite, although steady-state catalysis required the T2 copper center and did not require the T1 center. Finally, experiments separating rates of enzyme reduction from rates of reoxidation by nitrite demonstrated that the reaction with nitrite was rate limiting during catalysis. PMID:27055058

  13. MEK2 regulates ribonucleotide reductase activity through functional interaction with ribonucleotide reductase small subunit p53R2.

    Science.gov (United States)

    Piao, Chunmei; Youn, Cha-Kyung; Jin, Min; Yoon, Sang Pil; Chang, In-Youb; Lee, Jung Hee; You, Ho Jin

    2012-09-01

    The p53R2 protein, a newly identified member of the ribonucleotide reductase family that provides nucleotides for DNA damage repair, is directly regulated by p53. We show that p53R2 is also regulated by a MEK2 (ERK kinase 2/MAP kinase kinase 2)-dependent pathway. Increased MEK1/2 phosphorylation by serum stimulation coincided with an increase in the RNR activity in U2OS and H1299 cells. The inhibition of MEK2 activity, either by treatment with a MEK inhibitor or by transfection with MEK2 siRNA, dramatically decreased the serum-stimulated RNR activity. Moreover, p53R2 siRNA, but not R2 siRNA, significantly inhibits serum-stimulated RNR activity, indicating that p53R2 is specifically regulated by a MEK2-dependent pathway. Co-immunoprecipitation analyses revealed that the MEK2 segment comprising amino acids 65-171 is critical for p53R2-MEK2 interaction, and the binding domain of MEK2 is required for MEK2-mediated increased RNR activity. Phosphorylation of MEK1/2 was greatly augmented by ionizing radiation, and RNR activity was concurrently increased. Ionizing radiation-induced RNR activity was markedly attenuated by transfection of MEK2 or p53R2 siRNA, but not R2 siRNA. These data show that MEK2 is an endogenous regulator of p53R2 and suggest that MEK2 may associate with p53R2 and upregulate its activity. PMID:22895183

  14. The arsenic hyperaccumulating Pteris vittata expresses two arsenate reductases

    OpenAIRE

    Patrizia Cesaro; Chiara Cattaneo; Elisa Bona; Graziella Berta; Maria Cavaletto

    2015-01-01

    Enzymatic reduction of arsenate to arsenite is the first known step in arsenate metabolism in all organisms. Although the presence of one mRNA arsenate reductase (PvACR2) has been characterized in gametophytes of P. vittata, no arsenate reductase protein has been directly observed in this arsenic hyperaccumulating fern, yet. In order to assess the possible presence of arsenate reductase in P. vittata, two recombinant proteins, ACR2-His6 and Trx-His6-S-Pv2.5–8 were prepared in Escherichia coli...

  15. Novel Substrate Specificity and Temperature-Sensitive Activity of Mycosphaerella graminicola CYP51 Supported by the Native NADPH Cytochrome P450 Reductase

    OpenAIRE

    Price, Claire L.; Warrilow, Andrew G. S.; Parker, Josie E.; Mullins, Jonathan G. L.; Nes, W. David; Kelly, Diane E.; Kelly, Steven L.

    2015-01-01

    Mycosphaerella graminicola (Zymoseptoria tritici) is an ascomycete filamentous fungus that causes Septoria leaf blotch in wheat crops. In Europe the most widely used fungicides for this major disease are demethylation inhibitors (DMIs). Their target is the essential sterol 14α-demethylase (CYP51), which requires cytochrome P450 reductase (CPR) as its redox partner for functional activity. The M. graminicola CPR (MgCPR) is able to catalyze the sterol 14α-demethylation of eburicol and lanostero...

  16. A Multiscale, Mechanism-Driven, Dynamic Model for the Effects of 5α-Reductase Inhibition on Prostate Maintenance

    OpenAIRE

    Zager, Michael G.; Barton, Hugh A.

    2012-01-01

    A systems-level mathematical model is presented that describes the effects of inhibiting the enzyme 5α-reductase (5aR) on the ventral prostate of the adult male rat under chronic administration of the 5aR inhibitor, finasteride. 5aR is essential for androgen regulation in males, both in normal conditions and disease states. The hormone kinetics and downstream effects on reproductive organs associated with perturbing androgen regulation are complex and not necessarily intuitive. Inhibition of ...

  17. Bee Venom Promotes Hair Growth in Association with Inhibiting 5α-Reductase Expression.

    Science.gov (United States)

    Park, Seeun; Erdogan, Sedef; Hwang, Dahyun; Hwang, Seonwook; Han, Eun Hye; Lim, Young-Hee

    2016-06-01

    Alopecia is an important issue that can occur in people of all ages. Recent studies show that bee venom can be used to treat certain diseases including rheumatoid arthritis, neuralgia, and multiple sclerosis. In this study, we investigated the preventive effect of bee venom on alopecia, which was measured by applying bee venom (0.001, 0.005, 0.01%) or minoxidil (2%) as a positive control to the dorsal skin of female C57BL/6 mice for 19 d. Growth factors responsible for hair growth were analyzed by quantitative real-time PCR and Western blot analysis using mice skins and human dermal papilla cells (hDPCs). Bee venom promoted hair growth and inhibited transition from the anagen to catagen phase. In both anagen phase mice and dexamethasone-induced catagen phase mice, hair growth was increased dose dependently compared with controls. Bee venom inhibited the expression of SRD5A2, which encodes a type II 5α-reductase that plays a major role in the conversion of testosterone into dihydrotestosterone. Moreover, bee venom stimulated proliferation of hDPCs and several growth factors (insulin-like growth factor 1 receptor (IGF-1R), vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF)2 and 7) in bee venom-treated hDPCs dose dependently compared with the control group. In conclusion, bee venom is a potentially potent 5α-reductase inhibitor and hair growth promoter. PMID:27040904

  18. Structural Insight into Dihydrodipicolinate Reductase from Corybebacterium glutamicum for Lysine Biosynthesis.

    Science.gov (United States)

    Sagong, Hye-Young; Kim, Kyung-Jin

    2016-02-28

    Dihydrodipicolinate reductase is an enzyme that converts dihydrodipicolinate to tetrahydrodipicolinate using an NAD(P)H cofactor in L-lysine biosynthesis. To increase the understanding of the molecular mechanisms of lysine biosynthesis, we determined the crystal structure of dihydrodipicolinate reductase from Corynebacterium glutamicum (CgDapB). CgDapB functions as a tetramer, and each protomer is composed of two domains, an Nterminal domain and a C-terminal domain. The N-terminal domain mainly contributes to nucleotide binding, whereas the C-terminal domain is involved in substrate binding. We elucidated the mode of cofactor binding to CgDapB by determining the crystal structure of the enzyme in complex with NADP(+) and found that CgDapB utilizes both NADH and NADPH as cofactors. Moreover, we determined the substrate binding mode of the enzyme based on the coordination mode of two sulfate ions in our structure. Compared with Mycobacterium tuberculosis DapB in complex with its cofactor and inhibitor, we propose that the domain movement for active site constitution occurs when both cofactor and substrate bind to the enzyme. PMID:26502738

  19. Nitrofuran drugs as common subversive substrates of Trypanosoma cruzi lipoamide dehydrogenase and trypanothione reductase.

    Science.gov (United States)

    Blumenstiel, K; Schöneck, R; Yardley, V; Croft, S L; Krauth-Siegel, R L

    1999-12-01

    Lipoamide dehydrogenase (LipDH), trypanothione reductase (TR), and glutathione reductase (GR) catalyze the NAD(P)H-dependent reduction of disulfide substrates. TR occurs exclusively in trypanosomatids which lack a GR. Besides their physiological reactions, the flavoenzymes catalyze the single-electron reduction of nitrofurans with the concomitant generation of superoxide anions. Here, we report on the interaction of clinically used antimicrobial nitrofurans with LipDH and TR from Trypanosoma cruzi, the causative agent of Chagas' disease (South American trypanosomiasis), in comparison to mammalian LipDH and GR. The compounds were studied as inhibitors and as subversive substrates of the enzymes. None of the nitrofurans inhibited LipDH, although they did interfere with the disulfide reduction of TR and GR. When the compounds were studied as substrates, T. cruzi LipDH showed a high rate of nitrofuran reduction and was even more efficient than its mammalian counterpart. Several derivatives were also effective subversive substrates of TR, but the respective reaction with human GR was negligible. Nifuroxazide, nifuroxime, and nifurprazine proved to be the most promising derivatives since they were redox-cycled by both T. cruzi LipDH and TR and had pronounced antiparasitic effects in cultures of T. cruzi and Trypanosoma brucei. The results suggest that those nitrofuran derivatives which interact with both parasite flavoenzymes should be revisited as trypanocidal drugs. PMID:10571254

  20. Cloning, expression and crystallization of dihydrodipicolinate reductase from methicillin-resistant Staphylococcus aureus

    International Nuclear Information System (INIS)

    Given the recent rise in antimicrobial resistance, there is an urgent need to identify and characterize new antibiotic drug targets. One such target is dihydrodipicolinate reductase (DHDPR), which is an essential bacterial enzyme that catalyzes the second step in the lysine-biosynthesis pathway. In this paper, the cloning, expression, purification and crystallization of DHDPR from methicillin-resistant S. aureus are presented. Dihydrodipicolinate reductase (DHDPR; EC 1.3.1.26) catalyzes the nucleotide (NADH/NADPH) dependent second step of the lysine-biosynthesis pathway in bacteria and plants. Here, the cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of DHDPR from methicillin-resistant Staphylococcus aureus (MRSA-DHDPR) are presented. The enzyme was crystallized in a number of forms, predominantly with ammonium sulfate as a precipitant, with the best crystal form diffracting to beyond 3.65 Å resolution. Crystal structures of the apo form as well as of cofactor (NADPH) bound and inhibitor (2,6-pyridinedicarboxylate) bound forms of MRSA-DHDPR will provide insight into the structure and function of this essential enzyme and valid drug target

  1. Regulation of ribonucleotide reductase by Spd1 involves multiple mechanisms

    DEFF Research Database (Denmark)

    Nestoras, Konstantinos; Mohammed, Asma Hadi; Schreurs, Ann-Sofie; Fleck, Oliver; Watson, Adam T; Poitelea, Marius; O'Shea, Charlotte; Chahwan, Charly; Holmberg, Christian; Kragelund, Birthe B; Nielsen, Olaf; Osborne, Mark; Carr, Antony M; Liu, Cong

    2010-01-01

    The correct levels of deoxyribonucleotide triphosphates and their relative abundance are important to maintain genomic integrity. Ribonucleotide reductase (RNR) regulation is complex and multifaceted. RNR is regulated allosterically by two nucleotide-binding sites, by transcriptional control, and...

  2. Structural features of the ribonucleotide reductase of Aujeszky's disease virus.

    Science.gov (United States)

    Kaliman, A V; Boldogköi, Z; Fodor, I

    1994-01-01

    A gene construct of the Aujeszky's disease virus (ADV) genome was prepared and the DNA fragment encoding the ribonucleotide reductase was structurally characterized. We determined the entire DNA sequence of two adjacent open reading frames of the ribonucleotide reductase genes with the intergenic sequence of nine base pairs. From the sequence analysis we predict that Aujeszky's disease virus encodes a ribonucleotide reductase which comprises two polypeptides--large and small subunits, with sizes of 835 and 303 amino acids, respectively. Nucleotide and amino acid sequences of the large and small subunits of the Aujeszky's disease virus ribonucleotide reductase have been compared with that of other herpesviruses, and structural features of both proteins have been characterized. PMID:7810419

  3. HMG-CoA Reductase Inhibition Promotes Neurological Recovery, Peri-Lesional Tissue Remodeling, and Contralesional Pyramidal Tract Plasticity after Focal Cerebral Ischemia.

    Science.gov (United States)

    Kilic, Ertugrul; Reitmeir, Raluca; Kilic, Ülkan; Caglayan, Ahmet Burak; Beker, Mustafa Caglar; Kelestemur, Taha; Ethemoglu, Muhsine Sinem; Ozturk, Gurkan; Hermann, Dirk M

    2014-01-01

    3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors are widely used for secondary stroke prevention. Besides their lipid-lowering activity, pleiotropic effects on neuronal survival, angiogenesis, and neurogenesis have been described. In view of these observations, we were interested whether HMG-CoA reductase inhibition in the post-acute stroke phase promotes neurological recovery, peri-lesional, and contralesional neuronal plasticity. We examined effects of the HMG-CoA reductase inhibitor rosuvastatin (0.2 or 2.0 mg/kg/day i.c.v.), administered starting 3 days after 30 min of middle cerebral artery occlusion for 30 days. Here, we show that rosuvastatin treatment significantly increased the grip strength and motor coordination of animals, promoted exploration behavior, and reduced anxiety. It was associated with structural remodeling of peri-lesional brain tissue, reflected by increased neuronal survival, enhanced capillary density, and reduced striatal and corpus callosum atrophy. Increased sprouting of contralesional pyramidal tract fibers crossing the midline in order to innervate the ipsilesional red nucleus was noticed in rosuvastatin compared with vehicle-treated mice, as shown by anterograde tract tracing experiments. Western blot analysis revealed that the abundance of HMG-CoA reductase was increased in the contralesional hemisphere at 14 and 28 days post-ischemia. Our data support the idea that HMG-CoA reductase inhibition promotes brain remodeling and plasticity far beyond the acute stroke phase, resulting in neurological recovery. PMID:25565957

  4. Targeting the Large Subunit of Human Ribonucleotide Reductase for Cancer Chemotherapy

    Directory of Open Access Journals (Sweden)

    Prem Singh Kaushal

    2011-10-01

    Full Text Available Ribonucleotide reductase (RR is a crucial enzyme in de novo DNA synthesis, where it catalyses the rate determining step of dNTP synthesis. RRs consist of a large subunit called RR1 (α, that contains two allosteric sites and one catalytic site, and a small subunit called RR2 (β, which houses a tyrosyl free radical essential for initiating catalysis. The active form of mammalian RR is an anbm hetero oligomer. RR inhibitors are cytotoxic to proliferating cancer cells. In this brief review we will discuss the three classes of RR, the catalytic mechanism of RR, the regulation of the dNTP pool, the substrate selection, the allosteric activation, inactivation by ATP and dATP, and the nucleoside drugs that target RR. We will also discuss possible strategies for developing a new class of drugs that disrupts the RR assembly.

  5. Nitrite controls the release of nitric oxide in Pseudomonas aeruginosa cd1 nitrite reductase

    International Nuclear Information System (INIS)

    Nitrite reductase (cd1NIR) from Pseudomonas aeruginosa, which catalyses the reduction of nitrite to nitric oxide (NO), contains a c-heme as the electron acceptor and a d1-heme where catalysis occurs. Reduction involves binding of nitrite to the reduced d1-heme, followed by dehydration to yield NO; release of NO and re-reduction of the enzyme close the cycle. Since NO is a powerful inhibitor of ferrous hemeproteins, enzymatic turnover demands the release of NO. We recently discovered that NO dissociation from the ferrous d1-heme is fast, showing that cd1NIR behaves differently from other hemeproteins. Here we demonstrate for the first time that the physiological substrate nitrite displaces NO from the ferrous enzyme, which enters a new catalytic cycle; this reaction depends on the conserved His369 whose role in substrate stabilization is crucial for catalysis. Thus we suggest that also in vivo the activity of cd1NIR is controlled by nitrite

  6. Trapping of the Enoyl-Acyl Carrier Protein Reductase-Acyl Carrier Protein Interaction.

    Science.gov (United States)

    Tallorin, Lorillee; Finzel, Kara; Nguyen, Quynh G; Beld, Joris; La Clair, James J; Burkart, Michael D

    2016-03-30

    An ideal target for metabolic engineering, fatty acid biosynthesis remains poorly understood on a molecular level. These carrier protein-dependent pathways require fundamental protein-protein interactions to guide reactivity and processivity, and their control has become one of the major hurdles in successfully adapting these biological machines. Our laboratory has developed methods to prepare acyl carrier proteins (ACPs) loaded with substrate mimetics and cross-linkers to visualize and trap interactions with partner enzymes, and we continue to expand the tools for studying these pathways. We now describe application of the slow-onset, tight-binding inhibitor triclosan to explore the interactions between the type II fatty acid ACP from Escherichia coli, AcpP, and its corresponding enoyl-ACP reductase, FabI. We show that the AcpP-triclosan complex demonstrates nM binding, inhibits in vitro activity, and can be used to isolate FabI in complex proteomes. PMID:26938266

  7. Determination of the potency of a novel saw palmetto supercritical CO2 extract (SPSE for 5α-reductase isoform II inhibition using a cell-free in vitro test system

    Directory of Open Access Journals (Sweden)

    Pais P

    2016-04-01

    Full Text Available Pilar Pais, Agustí Villar, Santiago Rull Euromed, Barcelona, Spain Background: The nicotinamide adenine dinucleotide phosphate-dependent membrane protein 5α-reductase catalyses the conversion of testosterone to the most potent androgen – 5α-dihydrotestosterone. Two 5α-reductase isoenzymes are expressed in humans: type I and type II. The latter is found primarily in prostate tissue. Saw palmetto extract (SPE has been used extensively in the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia (BPH. The pharmacological effects of SPE include the inhibition of 5α-reductase, as well as anti-inflammatory and antiproliferative effects. Clinical studies of SPE have been inconclusive – some have shown significant results, and others have not – possibly the result of varying bioactivities of the SPEs used in the studies. Purpose: To determine the in vitro potency in a cell-free test system of a novel SP supercritical CO2 extract (SPSE, an inhibitor of the 5α-reductase isoenzyme type II. Materials and methods: The inhibitory potency of SPSE was compared to that of finasteride, an approved 5α-reductase inhibitor, on the basis of the enzymatic conversion of the substrate androstenedione to the 5α-reduced product 5α-androstanedione. Results: By concentration-dependent inhibition of 5α-reductase type II in vitro (half-maximal inhibitory concentration 3.58±0.05 µg/mL, SPSE demonstrated competitive binding toward the active site of the enzyme. Finasteride, the approved 5α-reductase inhibitor tested as positive control, led to 63%–75% inhibition of 5α-reductase type II. Conclusion: SPSE effectively inhibits the enzyme that has been linked to BPH, and the amount of extract required for activity is comparatively low. It can be confirmed from the results of this study that SPSE has bioactivity that promotes prostate health at a level that is superior to that of many other phytotherapeutic extracts. The

  8. Thiocyanate binding to the molybdenum centre of the periplasmic nitrate reductase from Paracoccus pantotrophus.

    Science.gov (United States)

    Butler, C S; Charnock, J M; Garner, C D; Thomson, A J; Ferguson, S J; Berks, B C; Richardson, D J

    2000-12-15

    The periplasmic nitrate reductase (NAP) from Paracoccus pantotrophus is a soluble two-subunit enzyme (NapAB) that binds two haem groups, a [4Fe-4S] cluster and a bis(molybdopterin guanine dinucleotide) (MGD) cofactor that catalyses the reduction of nitrate to nitrite. In the present study the effect of KSCN (potassium thiocyanate) as an inhibitor and Mo ligand has been investigated. Results are presented that show NAP is sensitive to SCN(-) (thiocyanate) inhibition, with SCN(-) acting as a competitive inhibitor of nitrate (K(i) approximately 4.0 mM). The formation of a novel EPR Mo(V) species with an elevated g(av) value (g(av) approximately 1.994) compared to the Mo(V) High-g (resting) species was observed upon redox cycling in the presence of SCN(-). Mo K-edge EXAFS analysis of the dithionite-reduced NAP was best fitted as a mono-oxo Mo(IV) species with three Mo-S ligands at 2.35 A (1 A=0.1 nm) and a Mo-O ligand at 2.14 A. The addition of SCN(-) to the reduced Mo(IV) NAP generated a sample that was best fitted as a mono-oxo (1.70 A) Mo(IV) species with four Mo-S ligands at 2.34 A. Taken together, the competitive nature of SCN(-) inhibition of periplasmic nitrate reductase activity, the elevated Mo(V) EPR g(av) value following redox cycling in the presence of SCN(-) and the increase in sulphur co-ordination of Mo(IV) upon SCN(-) binding, provide strong evidence for the direct binding of SCN(-) via a sulphur atom to Mo. PMID:11104696

  9. Proteasome inhibitor treatment in alcoholic liver disease

    Institute of Scientific and Technical Information of China (English)

    Fawzia Bardag-Gorce

    2011-01-01

    Oxidative stress, generated by chronic ethanol consumption, is a major cause of hepatotoxicity and liver injury. Increased production of oxygen-derived free radicals due to ethanol metabolism by CYP2E1 is principally located in the cytoplasm and in the mitochondria, which does not only injure liver cells, but also other vital organs, such as the heart and the brain. Therefore, there is a need for better treatment to enhance the antioxidant response elements. To date, there is no established treatment to attenuate high levels of oxidative stress in the liver of alcoholic patients. To block this oxidative stress, proteasome inhibitor treatment has been found to significantly enhance the antioxidant response elements of hepatocytes exposed to ethanol. Recent studies have shown in an experimental model of alcoholic liver disease that proteasome inhibitor treatment at low dose has cytoprotective effects against ethanol-induced oxidative stress and liver steatosis. The beneficial effects of proteasome inhibitor treatment against oxidative stress occurred because antioxidant response elements (glutathione peroxidase 2, superoxide dismutase 2, glutathione synthetase, glutathione reductase, and GCLC) were upregulated when rats fed alcohol were treated with a low dose of PS-341 (Bortezomib, Velcade(r)). This is an important finding because proteasome inhibitor treatment up-regulated reactive oxygen species removal and glutathione recycling enzymes, while ethanol feeding alone down-regulated these antioxidant elements. For the first time, it was shown that proteasome inhibition by a highly specific and reversible inhibitor is different from the chronic ethanol feeding-induced proteasome inhibition. As previously shown by our group, chronic ethanol feeding causes a complex dysfunction in the ubiquitin proteasome pathway, which affects the proteasome system, as well as the ubiquitination system. The beneficial effects of proteasome inhibitor treatment in alcoholic liver disease

  10. Transcripts of Anthocyanidin Reductase and Leucoanthocyanidin Reductase and Measurement of Catechin and Epicatechin in Tartary Buckwheat

    Directory of Open Access Journals (Sweden)

    Yeon Bok Kim

    2014-01-01

    Full Text Available Anthocyanidin reductase (ANR and leucoanthocyanidin reductase (LAR play an important role in the monomeric units biosynthesis of proanthocyanidins (PAs such as catechin and epicatechin in several plants. The aim of this study was to clone ANR and LAR genes involved in PAs biosynthesis and examine the expression of these two genes in different organs under different growth conditions in two tartary buckwheat cultivars, Hokkai T8 and T10. Gene expression was carried out by quantitative real-time RT-PCR, and catechin and epicatechin content was analyzed by high performance liquid chromatography. The expression pattern of ANR and LAR did not match the accumulation pattern of PAs in different organs of two cultivars. Epicatechin content was the highest in the flowers of both cultivars and it was affected by light in only Hokkai T8 sprouts. ANR and LAR levels in tartary buckwheat might be regulated by different mechanisms for catechin and epicatechin biosynthesis under light and dark conditions.

  11. Structure of the Francisella tularensis enoyl-acyl carrier protein reductase (FabI) in complex with NAD+ and triclosan

    International Nuclear Information System (INIS)

    Structure of the ternary complex of F. tularensis enoyl-acyl carrier protein reductase reveals the structure of the substrate binding loop whose electron density was missing in an earlier structure, and demonstrates a shift in the position of the NAD+ cofactor. Enoyl-acyl carrier protein reductase (FabI) catalyzes the last rate-limiting step in the elongation cycle of the fatty-acid biosynthesis pathway and has been validated as a potential antimicrobial drug target in Francisella tularensis. The development of new antibiotic therapies is important both to combat potential drug-resistant bioweapons and to address the broader societal problem of increasing antibiotic resistance among many pathogenic bacteria. The crystal structure of FabI from F. tularensis (FtuFabI) in complex with the inhibitor triclosan and the cofactor NAD+ has been solved to a resolution of 2.1 Å. Triclosan is known to effectively inhibit FabI from different organisms. Precise characterization of the mode of triclosan binding is required to develop highly specific inhibitors. Comparison of our structure with the previously determined FtuFabI structure which is bound to only NAD+ reveals the conformation of the substrate-binding loop, electron density for which was missing in the earlier structure, and demonstrates a shift in the conformation of the NAD+ cofactor. This shift in the position of the phosphate groups allows more room in the active site for substrate or inhibitor to bind and be better accommodated. This information will be crucial for virtual screening studies to identify novel scaffolds for development into new active inhibitors

  12. Effect of Tinospora cordifolia on experimental diabetic neuropathy

    Directory of Open Access Journals (Sweden)

    Pratibha D Nadig

    2012-01-01

    Conclusions: Tinospora cordifolia prevents the hyperalgesia in experimental diabetic neuropathy. It has an aldose reductase inhibitory activity in-vitro which may contribute to the beneficial effects.

  13. The role of biliverdin reductase in colorectal cancer

    International Nuclear Information System (INIS)

    In recent years, the effects of biliverdin and bilirubin have been studied extensively, and an inhibitory effect of bile pigments in cancer progression has been proposed. In this study we focused on the effects of biliverdin reductase, the enzyme that converts biliverdin to bilirubin, in colorectal cancer. For in vitro experiments we used a human colorectal carcinoma cell line and transfected it with an expression construct of shRNA specific for biliverdin reductase, to create cells with stable knock-down of enzyme expression. Cell proliferation was analyzed using the CASY model TT cell counting device. Western blot protein analysis was performed to study intracellular signaling cascades. Samples of human colorectal cancer were analyzed using immunohistochemistry. We were able to confirm the antiproliferative effects of bile pigments on cancer cells in vitro. However, this effect was attenuated in biliverdin reductase knock down cells. ERK and Akt activation seen under biliverdin and bilirubin treatment was also reduced in biliverdin reductase deficient cells. Immunohistochemical analysis of tumor samples from patients with colorectal cancer showed elevated biliverdin reductase levels. High enzyme expression was associated with lower overall and disease free patient survival. We conclude that BVR is required for bile pigment mediated effects regarding cancer cell proliferation and modulation of intracellular signaling cascades. The role of BVR overexpression in vivo and its exact influence on cancer progression and patient survival need to be further investigated. (author)

  14. Intramolecular electron transfer in Pseudomonas aeruginosa cd(1) nitrite reductase

    DEFF Research Database (Denmark)

    Farver, Ole; Brunori, Maurizio; Cutruzzolà, Francesca;

    2009-01-01

    The cd(1) nitrite reductases, which catalyze the reduction of nitrite to nitric oxide, are homodimers of 60 kDa subunits, each containing one heme-c and one heme-d(1). Heme-c is the electron entry site, whereas heme-d(1) constitutes the catalytic center. The 3D structure of Pseudomonas aeruginosa...... nitrite reductase has been determined in both fully oxidized and reduced states. Intramolecular electron transfer (ET), between c and d(1) hemes is an essential step in the catalytic cycle. In earlier studies of the Pseudomonas stutzeri enzyme, we observed that a marked negative cooperativity is...... controlling this internal ET step. In this study we have investigated the internal ET in the wild-type and His369Ala mutant of P. aeruginosa nitrite reductases and have observed similar cooperativity to that of the Pseudomonas stutzeri enzyme. Heme-c was initially reduced, in an essentially diffusion...

  15. Expression and site-directed mutagenesis of human dihydrofolate reductase

    International Nuclear Information System (INIS)

    A procaryotic high-level expression vector for human dihydrofolate reductase has been constructed and the protein characterized as a first step toward structure-function studies of this enzyme. A vector bearing the tac promoter, four synthetic oligodeoxynucleotides, and a restriction fragment from the dihydrofolate reductase cDNA were ligated in a manner which optimized the transcriptional and translational frequency of the enzyme mRNA. The reductase, comprising ca. 17% of the total soluble protein in the host bacteria, was purified to apparent homogeneity as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and characterized by amino acid composition, partial amino acid sequence, and steady-sate kinetic analysis. This expression vector has been used as a template for double-stranded plasmid DNA site-specific mutagenesis. Functional studies on a Cys-6 → Ser-6 mutant enzyme support the contention that Cys-6 is obligatory for organomercurial activation of human dihydrofolate reductase. The Ser-6 mutant enzyme was not activated to any extent following a 24-h incubation with p-(hydroxymercuri)benzoate and nicotinamide adenine dinucleotide phosphate (reduced) (NADPH), whereas the k/sub cat/ for Cys-6 reductase increased 2-fold under identical conditions. The specific activities of the Cys-6 and Ser-6 enzymes were virtually identical as determined by methotrexate titration as were the K/sub m/ values for both dihydrofolate and NADPH. The Ser-6 mutant showed a decreased temperature stability and was more sensitive to inactivation by α-chymotrypsin when compared to the wild-type enzyme. These results suggest that the Ser-6 mutant reductase is conformationally altered relative to the Cys-6 native enzyme

  16. Effect of vanadium on nitrate reductase activity in tomato leaves

    OpenAIRE

    J. Buczek

    2015-01-01

    The activity of nitrate reductase in cell-free extracts from tomato leaves is completely inhibited by 100 μM NaVO3 or VOCl2. In experiments in vivo vanadium ions inhibit the activity of the enzyme in 50 to 60 per cent. Addition of l mM vanadium to the medium on which tomato seedlings are grown causes after 24 h almost complete inhibition of nitrate reductase activity in cell-free extracts of the enzyme. Inhibition with vanadium may be abolished in experiments in vitro if the extract is treate...

  17. The intramolecular electron transfer between copper sites of nitrite reductase

    DEFF Research Database (Denmark)

    Farver, O; Eady, R R; Abraham, Z H;

    1998-01-01

    The intramolecular electron transfer (ET) between the type 1 Cu(I) and the type 2 Cu(II) sites of Alcaligenes xylosoxidans dissimilatory nitrite reductase (AxNiR) has been studied in order to compare it with the analogous process taking place in ascorbate oxidase (AO). This internal process is......(I) and the trinuclear copper centre in ascorbate oxidase, and the characteristics of the internal ET processes of these enzymes are compared. The data are consistent with the faster ET observed in nitrite reductase arising from a more advantageous entropy of activation when compared with ascorbate...

  18. Artificial electron donors for nitrate and nitrite reductases usable as mediators in amperometric biosensors

    Energy Technology Data Exchange (ETDEWEB)

    Strehlitz, B. (Umweltforschungszentrum Leipzig-Halle GmbH, Leipzig (Germany)); Gruendig, B. (Institut fuer Chemo- und Biosensorik, Muenster-Roxel (Germany)); Vorlop, K.D. (Bundesforschungsanstalt fuer Landwirtschaft, Braunschweig (Germany). Inst. fuer Technologie); Bartholmes, P. (Witten-Herdecke Univ., Witten (Germany). Inst. fuer Biochemie); Kotte, H. (Umweltforschungszentrum Leipzig-Halle GmbH, Leipzig (Germany)); Stottmeister, U. (Umweltforschungszentrum Leipzig-Halle GmbH, Leipzig (Germany))

    1994-07-01

    Various nitrate and nitrite reductases are capable of accepting electrons from artificial donors. Combining these redox active donors with an amperometric redox electrode which is covered with an immobilized layer of such a nitrate or nitrite reductase, new enzyme sensors can be created for the detection of nitrate or nitrite, respectively. A range of suitable electron donors for nitrate reductases and nitrite reductase from different sources have been selected and characterized by electrochemical methods. (orig.)

  19. S-nitrosoglutathione reductase inhibition regulates allergen-induced lung inflammation and airway hyperreactivity.

    Directory of Open Access Journals (Sweden)

    Maria E Ferrini

    Full Text Available Allergic asthma is characterized by Th2 type inflammation, leading to airway hyperresponsivenes, mucus hypersecretion and tissue remodeling. S-Nitrosoglutathione reductase (GSNOR is an alcohol dehydrogenase involved in the regulation of intracellular levels of S-nitrosothiols. GSNOR activity has been shown to be elevated in human asthmatic lungs, resulting in diminished S-nitrosothiols and thus contributing to increased airway hyperreactivity. Using a mouse model of allergic airway inflammation, we report that intranasal administration of a new selective inhibitor of GSNOR, SPL-334, caused a marked reduction in airway hyperreactivity, allergen-specific T cells and eosinophil accumulation, and mucus production in the lungs in response to allergen inhalation. Moreover, SPL-334 treatment resulted in a significant decrease in the production of the Th2 cytokines IL-5 and IL-13 and the level of the chemokine CCL11 (eotaxin-1 in the airways. Collectively, these observations reveal that GSNOR inhibitors are effective not only in reducing airway hyperresponsiveness but also in limiting lung inflammatory responses mediated by CD4(+ Th2 cells. These findings suggest that the inhibition of GSNOR may provide a novel therapeutic approach for the treatment of allergic airway inflammation.

  20. Inhibition of Albendazole and Oxfendazole on the Activity of Fumaric Reductase in Cysticercus cellulosae

    Institute of Scientific and Technical Information of China (English)

    GAO Xue-jun; LI Qing-zhang; LI Xia

    2004-01-01

    The activity of fumaric reductase in Cysticercus cellulosae tissue homogenate with albendazole and oxfendazole individually was detected. Results showed that the two kinds of drugs both could inhabite the activity of fumaric reductase. The results indicate that the mechanism of action of benzimidazole carbamate drugs is probably inhabiting the complex of fumaric reductase noncompetently, thus lead to the exhaostion of energy and death.

  1. Androgen replacement and/or 5 alpha reductase inhibitors in aging men.

    Science.gov (United States)

    Klotz, Laurence H

    2006-02-01

    A case study of a typical 65 year old man with symptoms of both LUTS with established BPH, and andropause, is presented. The case for 5ARI therapy versus androgen replacement therapy is discussed, and the evidence for the use of these drugs in combination is reviewed. PMID:16526981

  2. Evaluation of Enoyl-Acyl Carrier Protein Reductase Inhibitors as Pseudomonas aeruginosa Quorum-Quenching Reagents

    DEFF Research Database (Denmark)

    Yang, Liang; Liu, Yang; Sternberg, Claus;

    2010-01-01

    which block the quorum-sensing process can facilitate development of novel treatment strategies for P. aeruginosa infections. We have used molecular dynamics simulation and experimental studies to elucidate the efficiencies of two potential quorum-quenching reagents, triclosan and green tea...

  3. dNTP deficiency induced by HU via inhibiting ribonucleotide reductase affects neural tube development

    International Nuclear Information System (INIS)

    Highlights: • Murine NTDs were successfully induced by means of hydroxyurea (HU). • The impairment of dNTP was induced via inhibition of ribonucleotide reductase. • dNTP deficiency induced by HU caused defective DNA synthesis and repair. • Abnormal apoptosis and proliferation induced by HU affected neural tube development. - Abstract: Exposure to environmental toxic chemicals in utero during the neural tube development period can cause developmental disorders. To evaluate the disruption of neural tube development programming, the murine neural tube defects (NTDs) model was induced by interrupting folate metabolism using methotrexate in our previous study. The present study aimed to examine the effects of dNTP deficiency induced by hydroxyurea (HU), a specific ribonucleotide reductase (RNR) inhibitor, during murine neural tube development. Pregnant C57BL/6J mice were intraperitoneally injected with various doses of HU on gestation day (GD) 7.5, and the embryos were checked on GD 11.5. RNR activity and deoxynucleoside triphosphate (dNTP) levels were measured in the optimal dose. Additionally, DNA damage was examined by comet analysis and terminal deoxynucleotidyl transferase mediated dUTP nick end-labeling (TUNEL) assay. Cellular behaviors in NTDs embryos were evaluated with phosphorylation of histone H3 (PH-3) and caspase-3 using immunohistochemistry and western blot analysis. The results showed that NTDs were observed mostly with HU treatment at an optimal dose of 225 mg/kg b/w. RNR activity was inhibited and dNTP levels were decreased in HU-treated embryos with NTDs. Additionally, increased DNA damage, decreased proliferation, and increased caspase-3 were significant in NTDs embryos compared to the controls. Results indicated that HU induced murine NTDs model by disturbing dNTP metabolism and further led to the abnormal cell balance between proliferation and apoptosis

  4. Molecular modeling, structural analysis and identification of ligand binding sites of trypanothione reductase from Leishmania mexicana

    Directory of Open Access Journals (Sweden)

    Ozal Mutlu

    2013-01-01

    Full Text Available Background & objectives: Trypanothione reductase (TR is a member of FAD-dependent NADPH oxidoreductase protein family and it is a key enzyme which connects the NADPH and the thiol-based redox system. Inhibition studies indicate that TR is an essential enzyme for parasite survival. Therefore, it is an attractive target enzyme for novel drug candidates. There is no structural model for TR of Leishmania mexicana (LmTR in the protein databases. In this work, 3D structure of TR from L. mexicana was identified by template-based in silico homology modeling method, resultant model was validated, structurally analyzed and possible ligand binding pockets were identified. Methods: For computational molecular modeling study, firstly, template was identified by BLAST search against PDB database. Multiple alignments were achieved by ClustalW2. Molecular modeling of LmTR was done and possible drug targeting sites were identified. Refinement of the model was done by performing local energy minimization for backbone, hydrogen and side chains. Model was validated by web-based servers. Results: A reliable 3D model for TR from L. mexicana was modeled by using L. infantum trypanothione reductase (LiTR as a template. RMSD results according to C-alpha, visible atoms and backbone were 0.809 Å, 0.732 Å and 0.728 Å respectively. Ramachandran plot indicates that model shows an acceptable stereochemistry. Conclusion: Modeled structure of LmTR shows high similarity with LiTR based on overall structural features like domains and folding patterns. Predicted structure will provide a source for the further docking studies of various peptide-based inhibitors.

  5. Identification of a thioredoxin reductase from Babesia microti during mammalian infection.

    Science.gov (United States)

    Zhao, Shaoruo; Gong, Haiyan; Zhou, Yongzhi; Zhang, Houshuang; Cao, Jie; Zhou, Jinlin

    2016-08-01

    Babesia microti is the primary causative agent of human babesiosis worldwide and associated with increased human health risks and the safety of blood supply. The parasite replicates in the host's red blood cells, thus, in order to counteract the oxidative stress and toxic effects, parasites employ a thioredoxin (Trx) system to maintain a redox balance. Since thioredoxin reductase (TrxR) plays a critical role in the system, in this study, we report the cloning, expression, and functional characterization of a novel TrxR from B. microti (BmiTrxR). The complete gene BmiTrxR was obtained by amplifying the 5' and 3' regions of messenger RNA (mRNA) by RACE. The full-length complementary DNA (cDNA) of BmiTrxR was 1766 bp and contained an intact open reading frame with 1662 bp that encoded a polypeptide with 553 amino acids. Molecular weight of the predicted protein was 58.4 kDa with an isoelectric point of 6.95, similar to high molecular weight TrxR. The recombinant protein of BmiTrxR was expressed in a His-fused soluble form in Escherichia coli. The native protein BmiTrxR was identified with the mouse anti-BmiTrxR polyclonal serum by western blotting and IFAT. Moreover, the enzyme showed a disulfide reductase activity using DTNB as substrate and catalyzed the NADPH-dependent reduction of Trx. Auranofin, a known inhibitor of TrxR, completely abrogated the activity of the recombinant enzyme in vitro. These results not only contribute to the understanding of redox pathway in this parasite but also suggest that BmiTrxR could be a potential target for the development of novel strategies to control B. microti thus reducing the incidence of babesiosis. PMID:27164832

  6. Sepiapterin reductase deficiency an autosomal recessive DOPA-responsive dystonia

    NARCIS (Netherlands)

    N.G. Abeling; M. Duran; H.D. Bakker; L. Stroomer; B. Thony; N. Blau; J. Booij; B.T. Poll-The

    2006-01-01

    The diagnosis of a 14-year-old girl with a new homoallelic mutation in the sepiapterin reductase (SR) gene is reported. Initially she presented at the age of 2 with hypotonia and mild cognitive developmental delay, and was diagnosed as having mild methylmalonic aciduria, which was recently identifie

  7. Thioredoxin and NADP-thioredoxin reductase from cultured carrot cells

    Science.gov (United States)

    Johnson, T. C.; Cao, R. Q.; Kung, J. E.; Buchanan, B. B.

    1987-01-01

    Dark-grown carrot (Daucus carota L.) tissue cultures were found to contain both protein components of the NADP/thioredoxin system--NADP-thioredoxin reductase and the thioredoxin characteristic of heterotrophic systems, thioredoxin h. Thioredoxin h was purified to apparent homogeneity and, like typical bacterial counterparts, was a 12-kdalton (kDa) acidic protein capable of activating chloroplast NADP-malate dehydrogenase (EC 1.1.1.82) more effectively than fructose-1,6-bisphosphatase (EC 3.1.3.11). NADP-thioredoxin reductase (EC 1.6.4.5) was partially purified and found to be an arsenite-sensitive enzyme composed of two 34-kDa subunits. Carrot NADP-thioredoxin reductase resembled more closely its counterpart from bacteria rather than animal cells in acceptor (thioredoxin) specificity. Upon greening of the cells, the content of NADP-thioredoxin-reductase activity, and, to a lesser extent, thioredoxin h decreased. The results confirm the presence of a heterotrophic-type thioredoxin system in plant cells and raise the question of its physiological function.

  8. Bidirectional catalysis by copper-containing nitrite reductase

    NARCIS (Netherlands)

    Wijma, HJ; Canters, GW; de Vries, S; Verbeet, MP

    2004-01-01

    The copper-containing nitrite reductase from Alcaligenes faecalis S-6 was found to catalyze the oxidation of nitric oxide to nitrite, the reverse of its physiological reaction. Thermodynamic and kinetic constants with the physiological electron donor pseudoazurin were determined for both directions

  9. Thioredoxin reductase from s. Coelicolor as a drug target

    Czech Academy of Sciences Publication Activity Database

    Koháryová, M.; Brynda, Jiří; Řezáčová, Pavlína; Kollárová, M.

    2015-01-01

    Roč. 282, Suppl 1 (2015), s. 396. ISSN 1742-464X. [Congress of the Federation of European Biochemical Societies (FEBS) - The Biochemical Basis of Life /40./. 04.07.2015-09.07.2015, Berlin] Institutional support: RVO:61388963 ; RVO:68378050 Keywords : thioredoxin reductase * protein structure * drugs Subject RIV: CE - Biochemistry

  10. Isolation and expression of the Pneumocystis carinii dihydrofolate reductase gene

    DEFF Research Database (Denmark)

    Edman, J C; Edman, U; Cao, Mi-Mi;

    1989-01-01

    Pneumocystis carinii dihydrofolate reductase (DHFR; 5,6,7,8-tetrahydrofolate: NADP+ oxidoreductase, EC 1.5.1.3) cDNA sequences have been isolated by their ability to confer trimethoprim resistance to Escherichia coli. Consistent with the recent conclusion that P. carinii is a member of the Fungi...

  11. Fatty Acyl-CoA Reductase 1 Deficiency

    Directory of Open Access Journals (Sweden)

    Charles N Swisher

    2015-01-01

    Full Text Available Investigators from Erlangen, Germany; Calgary, CA; and Kafranbel, Syria, identified mutations in the gene, fatty acyl-CoA reductase 1 (FAR1 deficiency, adding to three other genes involved in plasmalogen biosynthesis, in two families affected by severe intellectual disability, early-onset epilepsy, microcephaly, congenital cataracts, growth retardation, and spasticity.

  12. Cell death in response to antimetabolites directed at ribonucleotide reductase and thymidylate synthase

    Directory of Open Access Journals (Sweden)

    Asuncion Valenzuela MM

    2015-02-01

    Full Text Available Malyn M Asuncion Valenzuela, Imilce Castro, Amber Gonda, Carlos J Diaz Osterman, Jessica M Jutzy, Jonathan R Aspe, Salma Khan, Jonathan W Neidigh, Nathan R Wall Center for Health Disparities and Molecular Medicine, Division of Biochemistry, Department of Basic Sciences, Loma Linda University, Loma Linda, CA, USA Abstract: New agent development, mechanistic understanding, and combinatorial partnerships with known and novel modalities continue to be important in the study of pancreatic cancer and its improved treatment. In this study, known antimetabolite drugs such as gemcitabine (ribonucleotide reductase inhibitor and 5-fluorouracil (thymidylate synthase inhibitor were compared with novel members of these two drug families in the treatment of a chemoresistant pancreatic cancer cell line PANC-1. Cellular survival data, along with protein and messenger ribonucleic acid expression for survivin, XIAP, cIAP1, and cIAP2, were compared from both the cell cytoplasm and from exosomes after single modality treatment. While all antimetabolite drugs killed PANC-1 cells in a time- and dose-dependent manner, neither family significantly altered the cytosolic protein level of the four inhibitors of apoptosis (IAPs investigated. Survivin, XIAP, cIAP1, and cIAP2 were found localized to exosomes where no significant difference in expression was recorded. This inability for significant and long-lasting expression may be a reason why pancreatic cancer lacks responsiveness to these and other cancer-killing agents. Continued investigation is required to determine the responsibilities of these IAPs in their role in chemoresistance in pancreatic adenocarcinoma. Keywords: IAPs, exosomes, pancreatic cancer, antimetabolites, gemcitabine, cladribine, hydroxyurea, 5-fluorodeoxyuridine, 5-fluorouracil

  13. Structures of trihydroxynaphthalene reductase-fungicide complexes: implications for structure-based design and catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Liao, D.-I.; Basarab, G.S.; Gatenby, A.A.; Valent, B.; Jordan, D.B. (DuPont)

    2010-03-08

    Trihydroxynaphthalene reductase catalyzes two intermediate steps in the fungal melanin biosynthetic pathway. The enzyme, a typical short-chain dehydrogenase, is the biochemical target of three commercial fungicides. The fungicides bind preferentially to the NADPH form of the enzyme. Three X-ray structures of the Magnaporthe grisea enzyme complexed with NADPH and two commercial and one experimental fungicide were determined at 1.7 {angstrom} (pyroquilon), 2.0 {angstrom} (2,3-dihydro-4-nitro-1H-inden-1-one, 1), and 2.1 {angstrom} (phthalide) resolutions. The chemically distinct inhibitors occupy similar space within the enzyme's active site. The three inhibitors share hydrogen bonds with the side chain hydroxyls of Ser-164 and Tyr-178 via a carbonyl oxygen (pyroquilon and 1) or via a carbonyl oxygen and a ring oxygen (phthalide). Active site residues occupy similar positions among the three structures. A buried water molecule that is hydrogen bonded to the NZ nitrogen of Lys-182 in each of the three structures likely serves to stabilize the cationic form of the residue for participation in catalysis. The pro S hydrogen of NADPH (which is transferred as a hydride to the enzyme's naphthol substrates) is directed toward the carbonyl carbon of the inhibitors that mimic an intermediate along the reaction coordinate. Modeling tetrahydroxynaphthalene and trihydroxynaphthalene in the active site shows steric and electrostatic repulsion between the extra hydroxyl oxygen of the former substrate and the sulfur atom of Met-283 (the C-terminal residue), which accounts, in part, for the 4-fold greater substrate specificity for trihydroxynaphthalene over tetrahydroxynaphthalene.

  14. Crystal structures of pinoresinol-lariciresinol and phenylcoumaran benzylic ether reductases and their relationship to isoflavone reductases

    Science.gov (United States)

    Min, Tongpil; Kasahara, Hiroyuki; Bedgar, Diana L.; Youn, Buhyun; Lawrence, Paulraj K.; Gang, David R.; Halls, Steven C.; Park, HaJeung; Hilsenbeck, Jacqueline L.; Davin, Laurence B.; Lewis, Norman G.; Kang, ChulHee

    2003-01-01

    Despite the importance of plant lignans and isoflavonoids in human health protection (e.g. for both treatment and prevention of onset of various cancers) as well as in plant biology (e.g. in defense functions and in heartwood development), systematic studies on the enzymes involved in their biosynthesis have only recently begun. In this investigation, three NADPH-dependent aromatic alcohol reductases were comprehensively studied, namely pinoresinol-lariciresinol reductase (PLR), phenylcoumaran benzylic ether reductase (PCBER), and isoflavone reductase (IFR), which are involved in central steps to the various important bioactive lignans and isoflavonoids. Of particular interest was in determining how differing regio- and enantiospecificities are achieved with the different enzymes, despite each apparently going through similar enone intermediates. Initially, the three-dimensional x-ray crystal structures of both PLR_Tp1 and PCBER_Pt1 were solved and refined to 2.5 and 2.2 A resolutions, respectively. Not only do they share high gene sequence similarity, but their structures are similar, having a continuous alpha/beta NADPH-binding domain and a smaller substrate-binding domain. IFR (whose crystal structure is not yet obtained) was also compared (modeled) with PLR and PCBER and was deduced to have the same overall basic structure. The basis for the distinct enantio-specific and regio-specific reactions of PCBER, PLR, and IFR, as well as the reaction mechanism and participating residues involved (as identified by site-directed mutagenesis), are discussed.

  15. The neurosteroidogenic enzyme 5α-reductase modulates the role of D1 dopamine receptors in rat sensorimotor gating.

    Science.gov (United States)

    Frau, Roberto; Mosher, Laura J; Bini, Valentina; Pillolla, Giuliano; Pes, Romina; Saba, Pierluigi; Fanni, Silvia; Devoto, Paola; Bortolato, Marco

    2016-01-01

    Neurosteroids exert diverse modulatory actions on dopamine neurotransmission and signaling. We previously documented that the enzyme 5α-reductase, which catalyzes the main rate-limiting step in neurosteroid synthesis, is required for the behavioral responses of Sprague-Dawley rats to non-selective dopaminergic agonists, such as the D1-D2 receptor agonist apomorphine. Specifically, systemic and intra-accumbal administrations of the 5α-reductase inhibitor finasteride countered apomorphine-induced deficits of sensorimotor gating, as measured by the prepulse inhibition (PPI) of the startle reflex; the classes of dopamine receptors involved in these effects, however, remain unknown. Prior rodent studies have revealed that the contributions of dopamine receptors to PPI regulation vary depending on the genetic background; thus, we analyzed the effect of finasteride on the PPI deficits induced by selective dopamine receptor agonists in Long-Evans (a strain exhibiting PPI deficits in response to both D1 and D2 receptor agonists) and Sprague-Dawley rats (which display PPI reductions following treatment with D2, and D3, but not D1 receptor agonists). In Long-Evans rats, finasteride opposed the PPI deficits induced by activation of D1, but not D2 receptors; conversely, in Sprague-Dawley rats, finasteride prevented the reductions in %PPI and accumbal dopamine extracellular levels caused by selective stimulation of D3, but not D2 receptors; however, the effects on %PPI were not confirmed by analyses on absolute PPI values. Our findings suggest that 5α-reductase modulates the effects of D1, but not D2 receptor agonists on sensorimotor gating. These data may help elucidate the role of neurosteroids in neuropsychiatric disorders featuring PPI deficits, including schizophrenia and Tourette syndrome. PMID:26415119

  16. A Single Conserved Residue Mediates Binding of the Ribonucleotide Reductase Catalytic Subunit RRM1 to RRM2 and Is Essential for Mouse Development

    DEFF Research Database (Denmark)

    Specks, Julia; Lecona, Emilio; Lopez-Contreras, Andres J.;

    2015-01-01

    The ribonucleotide reductase (RNR) complex, composed of a catalytic subunit (RRM1) and a regulatory subunit (RRM2), is thought to be a rate-limiting enzymatic complex for the production of nucleotides. In humans, the Rrm1 gene lies at 11p15.5, a tumor suppressor region, and RRM1 expression in......, despite being viable, leads to increased interaction of the RNR complex with its allosteric inhibitor Sml1. In contrast to yeast, homozygous mutant mice carrying the Rrm1 mutation (Rrm1WG/WG) are not viable, even at the earliest embryonic stages. Proteomic analyses failed to identify proteins that...

  17. Antitumor and radiosensitizing effects of (E)-2'-Deoxy-2'-(Fluoromethylene) cytidine, a novel inhibior of ribonucleotide diphosphate reductase on human colon carcinoma xenografts in nude mice.

    OpenAIRE

    Sun, Lin-Quan; Li, Ye-Xiong; Guillou, Louis; Mirimanoff, René-Olivier; Coucke, Philippe

    1997-01-01

    Antitumor and radiosensitizing effects of (E).2'-deoxy.2'-(fluromethyl ene) cytidine (FMdC), a novel inhibitor of ribonucleotide reductase, were evaluated on nude mice bearing s.c. xenografts and liver metastases of a human colon carcinoma. FMdC given once daily or twice weekly has a dose-dependent antitumor effect. The maximum tolerated dose In the mice was reached with 10 mgi'kg applied daily over 12 days. Twice weekly administration of FMdC reduced its toxicity but lowere...

  18. Crystallization and preliminary crystallographic studies of dihydrofolate reductase-thymidylate synthase from Trypanosoma cruzi, the Chagas disease pathogen

    International Nuclear Information System (INIS)

    Crystals of complexes of the T. cruzi dihydrofolate reductase-thymidylate synthase enzyme with three antifolates in two space groups have been obtained that diffracted to 2.1–2.8 Å resolution. The antifolates used for cocrystallization were dihydrotriazine-based and quinazoline-based antifolates. Trypanosoma cruzi dihydrofolate reductase-thymidylate synthase (TcDHFR-TS) was crystallized in complexes with the dihydrotriazine-based or quinazoline-based antifolates C-448, cycloguanil (CYC) and Q-8 in order to gain insight into the interactions of this DHFR enzyme with classical and novel inhibitors. The TcDHFR-TS–C-448–NDP–dUMP crystal belonged to space group C2221 with two molecules per asymmetric unit and diffracted to 2.37 Å resolution. The TcDHFR-TS–CYC, TcDHFR-TS–CYC–NDP and TcDHFR-TS–Q-8–NDP crystals belonged to space group P21 with four molecules per asymmetric unit and diffracted to 2.1, 2.6 and 2.8 Å resolution, respectively. Crystals belonging to the two different space groups were suitable for structure determination

  19. Proton pump inhibitors

    Science.gov (United States)

    Proton pump inhibitors (PPIs) are medicines that work by reducing the amount of stomach acid made by glands in ... Proton pump inhibitors are used to: Relieve symptoms of acid reflux, or gastroesophageal reflux disease (GERD). This is a ...

  20. Proton pump inhibitors

    Science.gov (United States)

    Proton pump inhibitors (PPIs) are medicines that work by reducing the amount of stomach acid made by ... Proton pump inhibitors are used to: Relieve symptoms of acid reflux, or gastroesophageal reflux disease (GERD). This ...

  1. Purification and characterization of a furfural reductase (FFR) from Escherichia coli strain LYO1--an enzyme important in the detoxification of furfural during ethanol production.

    Science.gov (United States)

    Gutiérrez, Tony; Ingram, Lonnie O; Preston, James F

    2006-01-24

    Furfural, an inhibitor of ethanol production from hemicellulose acid hydrolysates, is reductively detoxified to furfuryl alcohol by the ethanologenic bacterium Escherichia coli strain LYO1. Furfural reductase was purified 106-fold from this bacterium to approximately 50% homogeneity. It has a native molecular mass of 135 kDa, determined by gel filtration, and subunit molecular mass of approximately 68 kDa, determined by denaturing gel electrophoresis, indicating the holoenzyme is a dimer of two similar if not identical subunits. The enzyme shows strong activity from pH 4 to 8 (optimum pH 7.0), relatively high temperature tolerance (50-55 degrees C), and an apparent Km and Vmax for furfural of 1.5x10(-4)M and 28.5 micromol/min/mg of protein, respectively. It catalyzes the essentially irreversible reduction of furfural with NADPH, is specific for NADPH as cofactor, and is relatively specific for the reduction of furfural and benzaldehyde; 2-acetylfuran, xylose, and glucose were not reduced, while acetaldehyde was reduced at a rate 25-fold lower than furfural. This is the first description of a furfural reductase which, based upon size and substrate specificity, appears to represent a new type of alcohol-aldehyde oxido-reductase. The conversion of relatively toxic furfural to less toxic furfuryl alcohol suggests a beneficial role for this enzyme in mitigating furfural toxicity encountered during ethanol production from lignocellulosic biomass. PMID:16111779

  2. The effect of 5alpha-reductase inhibition with finasteride and dutasteride on bone mineral density in older men with benign prostatic hyperplasia.

    Science.gov (United States)

    Mačukat, Indira Radin; Spanjol, Josip; Orlič, Zeljka Crncevič; Butorac, Marta Zuvič; Marinovič, Marin; Ćupič, Dora Fučkar

    2014-09-01

    Testosterone is converted to dihyrotestosterone by two isoenzymes of 5alpha-reductase. Finasteride and dutasteride are 5alpha-reductase inhibitors commonly used in the treatment of benign prostatic hyperplasia. We compared indices of bone mineral density in 50 men treated with finasteride, 50 men treated with dutasteride and 50 men as control. Bone mineral density of spine and hip were measured using dual energy X-ray absorptiometry. Bone formation was assessed by measuring serum osteocalcin and bone resorptionby measuring serum C-terminal telopeptide of collagen type 1. In addition serum total testosteron and estradiol were determined. The dutasteride group had significantly higher mean bone min- eral density, mean bone mineral content, mean T score, mean Z score at femoral neck and mean total hip Z score than control. Mean total testosterone and estradiol levels were higher in the dutasteride group. There were no significant dif- ferences between the groups in lumbar spine bone density parameters or bone turnover markers. Our results provide evidence that long-term 5alpha-reductase suppression does not adversely affect bone mineral density. Dutasteride therapy could have beneficial effect on bone density. PMID:25507347

  3. Determination of plasma gluthatione reductase enzyme activity in osteoporotic women

    OpenAIRE

    Sadeghi N; Oveisi M.R.; Jannat B.; Hajimahmoodi M; Jamshidi A.R; Sajadian Z.

    2008-01-01

    Background: Osteoporosis is a disease of high prevalence with increased bone loss. Free radicals have been proved to be involved in bone resorption. Glutathione reductase (GR) plays an essential role in cell defense against reactive oxygen metabolites by sustaining the reduced status of an important antioxidant, glutathione. In the present study GR activity of plasma as an antioxidant enzyme in relation to Bone Mineral Density (BMD) was investigated.Material and Method: GR activity was measur...

  4. Glutathione reductase: solvent equilibrium and kinetic isotope effects

    International Nuclear Information System (INIS)

    Glutathione reductase catalyzes the NADPH-dependent reduction of oxidized glutathione (GSSG). The kinetic mechanism is ping-pong, and we have investigated the rate-limiting nature of proton-transfer steps in the reactions catalyzed by the spinach, yeast, and human erythrocyte glutathione reductases using a combination of alternate substrate and solvent kinetic isotope effects. With NADPH or GSSG as the variable substrate, at a fixed, saturating concentration of the other substrate, solvent kinetic isotope effects were observed on V but not V/K. Plots of Vm vs mole fraction of D2O (proton inventories) were linear in both cases for the yeast, spinach, and human erythrocyte enzymes. When solvent kinetic isotope effect studies were performed with DTNB instead of GSSG as an alternate substrate, a solvent kinetic isotope effect of 1.0 was observed. Solvent kinetic isotope effect measurements were also performed on the asymmetric disulfides GSSNB and GSSNP by using human erythrocyte glutathione reductase. The Km values for GSSNB and GSSNP were 70 microM and 13 microM, respectively, and V values were 62 and 57% of the one calculated for GSSG, respectively. Both of these substrates yield solvent kinetic isotope effects greater than 1.0 on both V and V/K and linear proton inventories, indicating that a single proton-transfer step is still rate limiting. These data are discussed in relationship to the chemical mechanism of GSSG reduction and the identity of the proton-transfer step whose rate is sensitive to solvent isotopic composition. Finally, the solvent equilibrium isotope effect measured with yeast glutathione reductase is 4.98, which allows us to calculate a fractionation factor for the thiol moiety of GSH of 0.456

  5. Internal electron transfer within mitochondrial succinate-cytochrome C reductase

    International Nuclear Information System (INIS)

    Internal electron transfer within succinate-cytochrome C reductase from pigeon breast muscle mitochondria was followed by the pulse radiolytic technique. The electron equivalent is transferred from an unknown donor to b type cytochrome(s), in a first order process with a rate constant of: 660 +- 150s-1. This process might be the rate determining step of electron transfer in mitochondria, since it is similar in rate to the turnover number of the mitochondrial respiratory chain

  6. Aldo-keto reductase (AKR) superfamily: Genomics and annotation

    OpenAIRE

    Mindnich Rebekka D; Penning Trevor M

    2009-01-01

    Abstract Aldo-keto reductases (AKRs) are phase I metabolising enzymes that catalyse the reduced nicotinamide adenine dinucleotide (phosphate) (NAD(P)H)-dependent reduction of carbonyl groups to yield primary and secondary alcohols on a wide range of substrates, including aliphatic and aromatic aldehydes and ketones, ketoprostaglan-dins, ketosteroids and xenobiotics. In so doing they functionalise the carbonyl group for conjugation (phase II enzyme reactions). Although functionally diverse, AK...

  7. Trypanosoma brucei DHFR-TS Revisited: Characterisation of a Bifunctional and Highly Unstable Recombinant Dihydrofolate Reductase-Thymidylate Synthase.

    Science.gov (United States)

    Gibson, Marc W; Dewar, Simon; Ong, Han B; Sienkiewicz, Natasha; Fairlamb, Alan H

    2016-05-01

    Bifunctional dihydrofolate reductase-thymidylate synthase (DHFR-TS) is a chemically and genetically validated target in African trypanosomes, causative agents of sleeping sickness in humans and nagana in cattle. Here we report the kinetic properties and sensitivity of recombinant enzyme to a range of lipophilic and classical antifolate drugs. The purified recombinant enzyme, expressed as a fusion protein with elongation factor Ts (Tsf) in ThyA- Escherichia coli, retains DHFR activity, but lacks any TS activity. TS activity was found to be extremely unstable (half-life of 28 s) following desalting of clarified bacterial lysates to remove small molecules. Stability could be improved 700-fold by inclusion of dUMP, but not by other pyrimidine or purine (deoxy)-nucleosides or nucleotides. Inclusion of dUMP during purification proved insufficient to prevent inactivation during the purification procedure. Methotrexate and trimetrexate were the most potent inhibitors of DHFR (Ki 0.1 and 0.6 nM, respectively) and FdUMP and nolatrexed of TS (Ki 14 and 39 nM, respectively). All inhibitors showed a marked drop-off in potency of 100- to 1,000-fold against trypanosomes grown in low folate medium lacking thymidine. The most potent inhibitors possessed a terminal glutamate moiety suggesting that transport or subsequent retention by polyglutamylation was important for biological activity. Supplementation of culture medium with folate markedly antagonised the potency of these folate-like inhibitors, as did thymidine in the case of the TS inhibitors raltitrexed and pemetrexed. PMID:27175479

  8. Perchlorate Reductase Is Distinguished by Active Site Aromatic Gate Residues.

    Science.gov (United States)

    Youngblut, Matthew D; Tsai, Chi-Lin; Clark, Iain C; Carlson, Hans K; Maglaqui, Adrian P; Gau-Pan, Phonchien S; Redford, Steven A; Wong, Alan; Tainer, John A; Coates, John D

    2016-04-22

    Perchlorate is an important ion on both Earth and Mars. Perchlorate reductase (PcrAB), a specialized member of the dimethylsulfoxide reductase superfamily, catalyzes the first step of microbial perchlorate respiration, but little is known about the biochemistry, specificity, structure, and mechanism of PcrAB. Here we characterize the biophysics and phylogeny of this enzyme and report the 1.86-Å resolution PcrAB complex crystal structure. Biochemical analysis revealed a relatively high perchlorate affinity (Km = 6 μm) and a characteristic substrate inhibition compared with the highly similar respiratory nitrate reductase NarGHI, which has a relatively much lower affinity for perchlorate (Km = 1.1 mm) and no substrate inhibition. Structural analysis of oxidized and reduced PcrAB with and without the substrate analog SeO3 (2-) bound to the active site identified key residues in the positively charged and funnel-shaped substrate access tunnel that gated substrate entrance and product release while trapping transiently produced chlorate. The structures suggest gating was associated with shifts of a Phe residue between open and closed conformations plus an Asp residue carboxylate shift between monodentate and bidentate coordination to the active site molybdenum atom. Taken together, structural and mutational analyses of gate residues suggest key roles of these gate residues for substrate entrance and product release. Our combined results provide the first detailed structural insight into the mechanism of biological perchlorate reduction, a critical component of the chlorine redox cycle on Earth. PMID:26940877

  9. Cloning and sequence of the human adrenodoxin reductase gene

    International Nuclear Information System (INIS)

    Adrenodoxin reductase is a flavoprotein mediating electron transport to all mitochondrial forms of cytochrome P450. The authors cloned the human adrenodoxin reductase gene and characterized it by restriction endonuclease mapping and DNA sequencing. The entire gene is approximately 12 kilobases long and consists of 12 exons. The first exon encodes the first 26 of the 32 amino acids of the signal peptide, and the second exon encodes the remainder of signal peptide and the apparent FAD binding site. The remaining 10 exons are clustered in a region of only 4.3 kilobases, separated from the first two exons by a large intron of about 5.6 kilobases. Two forms of human adrenodoxin reductase mRNA, differing by the presence or absence of 18 bases in the middle of the sequence, arise from alternate splicing at the 5' end of exon 7. This alternately spliced region is directly adjacent to the NADPH binding site, which is entirely contained in exon 6. The immediate 5' flanking region lacks TATA and CAAT boxes; however, this region is rich in G+C and contains six copies of the sequence GGGCGGG, resembling promoter sequences of housekeeping genes. RNase protection experiments show that transcription is initiated from multiple sites in the 5' flanking region, located about 21-91 base pairs upstream from the AUG translational initiation codon

  10. Identification of novel inhibitors of dietary lipid absorption using zebrafish.

    Directory of Open Access Journals (Sweden)

    Justin D Clifton

    Full Text Available Pharmacological inhibition of dietary lipid absorption induces favorable changes in serum lipoprotein levels in patients that are at risk for cardiovascular disease and is considered an adjuvant or alternative treatment with HMG-CoA reductase inhibitors (statins. Here we demonstrate the feasibility of identifying novel inhibitors of intestinal lipid absorption using the zebrafish system. A pilot screen of an unbiased chemical library identified novel compounds that inhibited processing of fluorescent lipid analogues in live zebrafish larvae. Secondary assays identified those compounds suitable for testing in mammals and provided insight into mechanism of action, which for several compounds could be distinguished from ezetimibe, a drug used to inhibit cholesterol absorption in humans that broadly inhibited lipid absorption in zebrafish larvae. These findings support the utility of zebrafish screening assays to identify novel compounds that target complex physiological processes.

  11. Substrate pathways and mechanisms of inhibition in the sulfur oxygenase reductase of Acidianus ambivalens

    Directory of Open Access Journals (Sweden)

    Andreas eVeith

    2011-03-01

    Full Text Available Background: The sulfur oxygenase reductase (SOR is the initial enzyme of the sulfur oxidation pathway in the thermoacidophilic Archaeon Acidianus ambivalens. The SOR catalyzes an oxygen-dependent sulfur disproportionation to H2S, sulfite and thiosulfate. The spherical, hollow, cytoplasmic enzyme is composed of 24 identical subunits with an active site pocket each comprising a mononuclear non-heme iron site and a cysteine persulfide. Substrate access and product exit occur via apolar chimney-like protrusions at the four-fold symmetry axes, via narrow polar pores at the three-fold symmetry axes and via narrow apolar pores within in each subunit. In order to investigate the function of the pores we performed site-directed mutagenesis and inhibitor studies. Results: Truncation of the chimney-like protrusions resulted in an up to seven-fold increase in specific enzyme activity compared to the wild type. Replacement of the salt bridge-forming Arg99 residue by Ala at the three-fold symmetry axes doubled the activity and introduced a bias towards reduced reaction products. Replacement of Met296 and Met297, which form the active site pore, lowered the specific activities by 25-55 % with the exception of an M296V mutant. X-ray crystallography of SOR wild type crystals soaked with inhibitors showed that Hg2+ and iodoacetamide bind to cysteines within the active site, whereas Zn2+ binds to a histidine in a side channel of the enzyme. The Zn2+ inhibition was partially alleviated by mutation of the His residue. Conclusions: The expansion of the pores in the outer shell led to an increased enzyme activity while the integrity of the active site pore seems to be important. Hg2+ and iodoacetamide block cysteines in the active site pocket, while Zn2+ interferes over a distance, possibly by restriction of protein flexibility or substrate access or product exit.

  12. Steroid 5α-reductase as a novel therapeutic target for schizophrenia and other neuropsychiatric disorders.

    Science.gov (United States)

    Paba, Silvia; Frau, Roberto; Godar, Sean C; Devoto, Paola; Marrosu, Francesco; Bortolato, Marco

    2011-01-01

    The enzyme steroid 5α reductase (S5α R) catalyzes the conversion of Δ⁴-3-ketosteroid precursors--such as testosterone, progesterone and androstenedione--into their 5α-reduced metabolites. Although the current nomenclature assigns five enzymes to the S5α R family, only the types 1 and 2 appear to play an important role in steroidogenesis, mediating an overlapping set of reactions, albeit with distinct chemical characteristics and anatomical distribution. The discovery that the 5α-reduced metabolite of testosterone, 5α-dihydrotestosterone (DHT), is the most potent androgen and stimulates prostatic growth led to the development of S5α R inhibitors with high efficacy and tolerability. Two of these agents, finasteride and dutasteride, have received official approval for the treatment of benign prostatic hyperplasia and are being tested for prevention of prostate cancer. Finasteride is also approved for male-pattern alopecia and has been shown to induce very limited side effects. Over the last decade, converging lines of evidence have highlighted the role of 5α-reduced steroids and their precursors in brain neurotransmission and behavioral regulation. Capitalizing on these premises, we and other groups have recently investigated the role of S5α R in neuropsychiatric disorders. Our preliminary data suggest that S5 R inhibitors may elicit therapeutic effects in a number of disorders associated to dopaminergic hyperreactivity, including psychotic disorders, Tourette syndrome and impulse control disorders. In the present article, we review emerging preclinical and clinical evidence related to these effects, and discuss some of the potential mechanisms underlying the role of S5α R in the pathophysiology of mental disorders. PMID:21361868

  13. Structure of octaheme cytochrome c nitrite reductase from Thioalkalivibrio nitratireducens in a complex with phosphate

    International Nuclear Information System (INIS)

    Octaheme cytochrome c nitrite reductase from Thioalkalivibrio nitratireducens (TvNiR) catalyzes the reduction of nitrite and hydroxylamine to ammonia. The structures of the free enzyme and of the enzyme in complexes with the substrate (nitrite ion) and the inhibitor (azide ion) have been solved previously. In this study we report the structures of the oxidized complex of TvNiR with phosphate and of this complex reduced by europium(II) chloride (1.8- and 2.0-A resolution, the R factors are 15.9 and 16.7%, respectively) and the structure of the enzyme in the complex with cyanide (1.76-A resolution, the R factor is 16.5%), which was prepared by soaking a crystal of the oxidized phosphate complex of TvNiR. In the active site of the enzyme, the phosphate ion binds to the iron ion of the catalytic heme and to the side chains of the catalytic residues Arg131, Tyr303, and His361. The cyanide ion is coordinated to the heme-iron ion and is hydrogen bonded to the residue His361. In the structure of reduced TvNiR, the phosphate ion is bound in the same manner as in the structure of oxidized TvNiR, and the ninecoordinated europium ion is located on the surface of one of the crystallographically independent monomers of the enzyme.

  14. Non-native ligands define the active site of Pennisetum glaucum (L.) R. Br dehydroascorbate reductase.

    Science.gov (United States)

    Krishna Das, Bhaba; Kumar, Amit; Maindola, Priyank; Mahanty, Srikrishna; Jain, S K; Reddy, Mallireddy K; Arockiasamy, Arulandu

    2016-05-13

    Dehydroascorbate reductase (DHAR), a member of the glutathione-S-transferase (GST) family, reduces dehydroascorbate (DHA) to ascorbate (AsA; Vitamin-C) in a glutathione (GSH)-dependent manner and in doing so, replenishes the critical AsA pool of the cell. To understand the enzyme mechanism in detail, we determined the crystal structure of a plant DHAR from Pennisetum glaucum (PgDHAR) using Iodide-Single Anomalous Dispersion (SAD) and Molecular replacement methods, in two different space groups. Here, we show PgDHAR in complex with two non-native ligands, viz. an acetate bound at the G-site, which resembles the γ-carboxyl moiety of GSH, and a glycerol at the H-site, which shares the backbone of AsA. We also show that, in the absence of bound native substrates, these non-native ligands help define the critical 'hook points' in the DHAR enzyme active site. Further, our data suggest that these non-native ligands can act as the logical bootstrapping points for iterative design of inhibitors/analogs for DHARs. PMID:27067046

  15. Modeling Steroid 5alpha-reductase and Characterizing Its Potential Active Sites

    Institute of Scientific and Technical Information of China (English)

    OU Min-Rui; LI Jun-Qian

    2012-01-01

    Steroid 5alpha-reductase of human is an enzyme in the biosynthetic pathway from testosterone (T) to dihydrotestosterone (DHT). Up to now, no crystal structure of this enzyme has been reported. However, knowledge of the tertiary structure and possible active sites is essential for understanding the catalysis mechanism and for the design of inhibitors. A model with putative active sites has been created and evaluated by using homology modeling and molecular docking techniques based on the bioinformatics knowledge. The homology model is optimized in Swiss PDB Viewer with MM method and substrate structures before docking are also optimized on HF/6-31G. The active site for the docking of NADP, T, DHT and Finasteride is located near the N-terminus of enzyme. Four active amino acids in the active site are identified as Ala26, Arg53, Arg176 and Lys177. Reaction procedure, binding pattern of active sites, the types of weak interaction and so on are also discussed.

  16. Structural basis for allosteric regulation of human ribonucleotide reductase by nucleotide-induced oligomerization

    Energy Technology Data Exchange (ETDEWEB)

    Fairman, James Wesley; Wijerathna, Sanath Ranjan; Ahmad, Md Faiz; Xu, Hai; Nakano, Ryo; Jha, Shalini; Prendergast, Jay; Welin, R. Martin; Flodin, Susanne; Roos, Annette; Nordlund, Pär; Li, Zongli; Walz, Thomas; Dealwis, Chris Godfrey (Case Western); (Harvard-Med); (Karolinska); (Tennessee-K)

    2011-07-25

    Ribonucleotide reductase (RR) is an {alpha}{sub n}{beta}{sub n} (RR1-RR2) complex that maintains balanced dNTP pools by reducing NDPs to dNDPs. RR1 is the catalytic subunit, and RR2 houses the free radical required for catalysis. RR is allosterically regulated by its activator ATP and its inhibitor dATP, which regulate RR activity by inducing oligomerization of RR1. Here, we report the first X-ray structures of human RR1 bound to TTP alone, dATP alone, TTP-GDP, TTP-ATP, and TTP-dATP. These structures provide insights into regulation of RR by ATP or dATP. At physiological dATP concentrations, RR1 forms inactive hexamers. We determined the first X-ray structure of the RR1-dATP hexamer and used single-particle electron microscopy to visualize the {alpha}{sub 6}-{beta}{beta}'-dATP holocomplex. Site-directed mutagenesis and functional assays confirm that hexamerization is a prerequisite for inhibition by dATP. Our data indicate a mechanism for regulating RR activity by dATP-induced oligomerization.

  17. Decreased GSSG reductase activity enhances cellular zinc toxicity in three human lung cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Walther, U.I.; Czermak, A.; Mueckter, H.; Walther, S.C.; Fichtl, B. [Walther-Straub-Institut fuer Pharmakologie und Toxikologie, Ludwig-Maximilians-Universitaet Muenchen, Nussbaumstr. 26, 80336, Muenchen (Germany)

    2003-03-01

    Cellular reduced glutathione (GSH) levels have been identified as an essential determinant in zinc-induced cytotoxicity. However, cytotoxic effects of zinc have also been observed without depletion of GSH stores. In a previous study, the intracellular activity of GSSG reductase (GR) has come into focus (Walther et al. 2000, Biol Trace Elem Res 78:163-177). In the present paper we have tried to address this issue more deeply by inhibiting the activity of cellular GR without any appreciable decreases of cellular glutathione. In three pulmonary cell lines, GR activity was inhibited in a dose-dependent manner by the alkylating agent carmustine (BCNU), a known inhibitor of GR. Cells were pretreated with BCNU for 14 h, followed by exposure to various concentrations of zinc chloride. Then we determined the incorporation of radiolabelled methionine (to assess protein synthesis), and measured the GSH and oxidized glutathione (GSSG) levels. Additionally, GR activity of controls was measured. IC{sub 50} values for zinc-induced inhibition of methionine incorporation, as well as GSH contents, was strongly correlated to the decreased GR activity. These results firmly suggest that GR is an important factor in the event chain of zinc cytotoxicity. Together with the results from our previously cited study where impaired regeneration of GSH levels were accompanied by a decrease in total cellular glutathione (GSH + GSSG) we conclude that GSSG itself is an important effector in zinc cytotoxicity. (orig.)

  18. In vitro effects of myricetin, morin, apigenin, (+)-taxifolin, (+)-catechin, (−)-epicatechin, naringenin and naringin on cytochrome b5 reduction by purified NADH-cytochrome b5 reductase

    International Nuclear Information System (INIS)

    Highlights: • We assessed inhibitory effects of 8 dietary flavonoids on cytochrome b5 reduction by purified NADH-cytochrome b5 reductase. • The flavonol myricetin was the most potent in inhibiting cytochrome b5 reduction with an IC50 value of 0.35 μM. • We investigated kinetics of myricetin-induced inhibition in detail. • We explored the structure–inhibitory activity relationship of compounds. • Modulation of cytochrome b5 reduction indicates a potential for myricetin to lead to some food–drug/xenobiotic interactions. - Abstract: The microsomal NADH-dependent electron transport system consisting of cytochrome b5 reductase and cytochrome b5 participates in a number of physiologically important processes including lipid metabolism as well as is involved in the metabolism of various drug and xenobiotics. In the present study, we assessed the inhibitory effects of eight dietary flavonoids representing five distinct chemical classes on cytochrome b5 reduction by purified cytochrome b5 reductase. From the flavonoids tested, myricetin was the most potent in inhibiting cytochrome b5 reduction with an IC50 value of 0.35 μM. Myricetin inhibited b5 reductase noncompetitively with a Ki of 0.21 μM with respect to cofactor NADH, and exhibited a non-linear relationship indicating non-Michaelis–Menten kinetic binding with respect to cytochrome b5. In contrast to the potent inhibitory activity of myricetin, (+)-taxifolin was found to be a weak inhibitor (IC50 = 9.8 μM). The remaining flavonoids were inactive within the concentration range tested (1–50 μM). Analysis of structure–activity data suggested that simultaneous presence of three OH groups in ring B is a primary structural determinant for a potent enzyme inhibition. Our results suggest that inhibition of the activity of this system by myricetin or myricetin containing diets may influence the metabolism of therapeutic drugs as well as detoxification of xenobiotics

  19. Immunological comparison of the NADH:nitrate reductase from different cucumber tissues

    OpenAIRE

    Jolanta Marciniak; Grażyna Kłobus; Józef Buczek; Tadeusz Stefaniak; Jarosław Mazur

    2014-01-01

    Soluble nitrate reductase from cucumber roots (Cucumis sativus L.) was isolated and purified with blue-Sepharose 4B. Specific antibodies against the NR protein were raised by immunization of a goat. Using polyclonal antibodies anti-NR properties of the nitrate reductase from various cucumber tissues were examined. Experiments showed difference in immuno-logical properties of nitrate reductase (NR) from cotyledon roots and leaves.

  20. Immunological comparison of the NADH:nitrate reductase from different cucumber tissues

    Directory of Open Access Journals (Sweden)

    Jolanta Marciniak

    2014-02-01

    Full Text Available Soluble nitrate reductase from cucumber roots (Cucumis sativus L. was isolated and purified with blue-Sepharose 4B. Specific antibodies against the NR protein were raised by immunization of a goat. Using polyclonal antibodies anti-NR properties of the nitrate reductase from various cucumber tissues were examined. Experiments showed difference in immuno-logical properties of nitrate reductase (NR from cotyledon roots and leaves.

  1. Histochemical Localization of Glutathione Dependent NBT-Reductase in Mouse Skin

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective Localization of the glutathione dependent Nitroblue tetrazolium (NBT) reductase in fresh frozen sections of mouse skin and possible dependence of NBT reductase on tissue thiol levels has been investigated. Methods The fresh frozen tissue sections (8m thickness) were prepared and incubated in medium containing NBT, reduced glutathione (GSH) and phosphate buffer. The staining for GSH was performed with mercury orange. Results  The activity of the NBT-reductase in mouse skin has been found to be localized in the areas rich in glutathione and actively proliferating area of the skin. Conclusion The activity of the NBT-reductase seems to be dependent on the glutathione contents.

  2. High-resolution structures of Thermus thermophilus enoyl-acyl carrier protein reductase in the apo form, in complex with NAD+ and in complex with NAD+ and triclosan

    International Nuclear Information System (INIS)

    T. thermophilus enoyl-acyl carrier protein reductase was crystallized in the apo form, with NAD+ bound and with NAD+ and the inhibitor triclosan bound. The structures were solved by molecular replacement and refined at 1.50, 1.86 and 1.90 Å resolution, respectively. The structures are described, analysed and compared with those of enoyl-acyl carrier protein reductases from other species. Enoyl-acyl carrier protein reductase (ENR; the product of the fabI gene) is an important enzyme that is involved in the type II fatty-acid-synthesis pathway of bacteria, plants, apicomplexan protozoa and mitochondria. Harmful pathogens such as Mycobacterium tuberculosis and Plasmodium falciparum use the type II fatty-acid-synthesis system, but not mammals or fungi, which contain a type I fatty-acid-synthesis pathway consisting of one or two multifunctional enzymes. For this reason, specific inhibitors of ENR are attractive antibiotic candidates. Triclosan, a broad-range antibacterial agent, binds to ENR, inhibiting fatty-acid synthesis. As humans do not have an ENR enzyme, they are not affected. Here, high-resolution structures of Thermus thermophilus (Tth) ENR in the apo form, bound to NAD+ and bound to NAD+ plus triclosan are reported. Differences from and similarities to other known ENR structures are reported; in general, the structures are very similar. The cofactor-binding site is also very similar to those of other ENRs and, as reported for other species, triclosan leads to greater ordering of the loop that covers the cofactor-binding site, which, together with the presence of triclosan itself, presumably provides tight binding of the dinucleotide, preventing cycling of the cofactor. Differences between the structures of Tth ENR and other ENRs are the presence of an additional β-sheet at the N-terminus and a larger number of salt bridges and side-chain hydrogen bonds. These features may be related to the high thermal stability of Tth ENR

  3. Crystallization and preliminary X-ray crystallographic studies of enoyl-acyl carrier protein reductase (FabI) from Psuedomonas aeruginosa

    International Nuclear Information System (INIS)

    Enoyl-acyl carrier protein reductase (FabI) from P. aeruginosa was purified and crystallized. FabI was also cocrystallized with the inhibitor triclosan and the cofactor NADH. Crystals of native and complexed FabI diffracted to resolutions of 2.6 and 1.8 Å, respectively. During fatty-acid biosynthesis, enoyl-acyl carrier protein (enoyl-ACP) reductase catalyzes the reduction of trans-2-enoyl-ACP to fully saturated acyl-ACP via the ubiquitous fatty-acid synthase system. NADH-dependent enoyl-ACP reductase (FabI) from Pseudomonas aeruginosa has been purified and crystallized as an apoenzyme and in a complex form with NADH and triclosan. Triclosan is an inhibitor of FabI and forms a stable ternary complex in the presence of NADH. The crystals of native and complexed FabI diffracted to resolutions of 2.6 and 1.8 Å, respectively. The crystals both belonged to space group P21, with unit-cell parameters a = 117.32, b = 155.844, c = 129.448 Å, β = 111.061° for the native enzyme and a = 64.784, b = 107.573, c = 73.517 Å, β = 116.162° for the complex. Preliminary molecular replacement further confirmed the presence of four tetramers of native FabI and one tetramer of the complex in the asymmetric unit, corresponding to Matthews coefficients (VM) of 2.46 and 2.05 Å3 Da−1 and solvent contents of 50.1 and 40.1%, respectively

  4. Substrate-dependent modulation of the enzymatic catalytic activity: reduction of nitrate, chlorate and perchlorate by respiratory nitrate reductase from Marinobacter hydrocarbonoclasticus 617.

    Science.gov (United States)

    Marangon, Jacopo; Paes de Sousa, Patrícia M; Moura, Isabel; Brondino, Carlos D; Moura, José J G; González, Pablo J

    2012-07-01

    The respiratory nitrate reductase complex (NarGHI) from Marinobacter hydrocarbonoclasticus 617 (Mh, formerly Pseudomonas nautica 617) catalyzes the reduction of nitrate to nitrite. This reaction is the first step of the denitrification pathway and is coupled to the quinone pool oxidation and proton translocation to the periplasm, which generates the proton motive force needed for ATP synthesis. The Mh NarGH water-soluble heterodimer has been purified and the kinetic and redox properties have been studied through in-solution enzyme kinetics, protein film voltammetry and spectropotentiometric redox titration. The kinetic parameters of Mh NarGH toward substrates and inhibitors are consistent with those reported for other respiratory nitrate reductases. Protein film voltammetry showed that at least two catalytically distinct forms of the enzyme, which depend on the applied potential, are responsible for substrate reduction. These two forms are affected differentially by the oxidizing substrate, as well as by pH and inhibitors. A new model for the potential dependence of the catalytic efficiency of Nars is proposed. PMID:22561116

  5. The effect of copper and gallium compounds on ribonucleotide reductase

    Energy Technology Data Exchange (ETDEWEB)

    Narasimhan, J.

    1992-01-01

    The mode of action of copper complexes (CuL and CuKTS) and gallium compounds (gallium nitrate and citrate) in cytotoxicity was studied. The effects of these agents on the enzyme ribonucleotide reductase was investigated by monitoring the tyrosyl free radical present in the active site of the enzyme through electron spin resonance (ESR) spectroscopy. Ribonucleotide reductase, a key enzyme in cellular proliferation, consists of two subunits. M1, a dimer of molecular weight 170,000 contains the substrate and effector binding sites. M2, a dimer of molecular weight 88,000, contains non-heme iron and tyrosyl free radical essential for the activity of the enzyme. In studies using copper complexes, the cellular oxidative chemistry was examined by ESR studies on adduct formation with membranes, and oxidation of thiols. Membrane thiols were oxidized through the reduction of the ESR signal of the thiol adduct and the analysis of sulfhydryl content. Using the radiolabel [sup 59]Fe, the inhibitory action of copper thiosemicarbazones on cellular iron uptake was shown. The inhibitory action of CuL on ribonucleotide reductase was shown by the quenching of the tyrosyl free radical on the M2 subunit. The hypothesis that gallium directly interacts with the M2 subunit of the enzyme and displaces the iron from it was proven. The tyrosyl free radical signal from cell lysates was inhibited by the direct addition of gallium compounds. Gallium content in the cells was measured by a fluorimetric method, to ensure the presence of sufficient amounts of gallium to compete with the iron in the M2 subunit. The enzyme activity, measured by the conversion of [sup 14]C-CDP to the labeled deoxy CDP, was inhibited by the addition of gallium nitrate in a cell free assay system. The immunoprecipitation studies of the [sup 59]Fe labeled M2 protein using the monoclonal antibody directed against this subunit suggested that gallium releases iron from the M2 subunit.

  6. biliverdin. Is there a role for biliverdin reductase?

    Directory of Open Access Journals (Sweden)

    AndreasDaiber

    2012-03-01

    Full Text Available Reactive oxygen species (ROS and signaling events are involved in the pathogenesis of endothelial dysfunction and represent a major contribution to vascular regulation. Molecular signaling is highly dependent on reactive oxygen species. But depending on the amount of ROS production it might have toxic or protective effects. Despite a large number of negative outcomes in large clinical trials (e.g. HOPE, HOPE-TOO, antioxidant molecules and agents are important players to influence the critical balance between production and elimination of RONS. However, chronic systemic antioxidant therapy lacks clinical efficacy, probably by interfering with important physiological redox signaling pathways. Therefore, it may be a much more promising attempt to induce intrinsic antioxidant pathways in order to increase the antioxidants not systemically but at the place of oxidative stress and complications. Among others, heme oxygenase (HO has been shown to be important for attenuating the overall production of ROS in a broad range of disease states through its ability to degrade heme and to produce carbon monoxide (CO, biliverdin/bilirubin, and the release of free iron with subsequent ferritin induction. With the present review we would like to highlight the important antioxidant role of the heme oxygenase system and especially discuss the contribution of the biliverdin, bilirubin and biliverdin reductase to these beneficial effects. The bilierdin reductase was reported to confer an antioxidant redox amplification cycle by which low, physiological bilirubin concentrations confer potent antioxidant protection via recycling of biliverdin from oxidized bilirubin by the biliverdin reductase, linking this sink for oxidants to the NADPH pool. To date the existence and role of this antioxidant redox cycle is still under debate and we present and discuss the pros and cons as well as our own findings on this topic.

  7. Substrate Specificity, Inhibitor Selectivity and Structure-Function Relationships of Aldo-Keto Reductase 1B15: A Novel Human Retinaldehyde Reductase

    Czech Academy of Sciences Publication Activity Database

    Giménez-Dejoz, J.; Kolář, Michal H.; Ruiz, F. X.; Crespo, I.; Cousido-Siah, A.; Podjarny, A.; Barski, O. A.; Fanfrlík, Jindřich; Parés, X.; Farrés, J.; Porté, S.

    2015-01-01

    Roč. 10, č. 7 (2015), e0134506/1-e0134506/19. E-ISSN 1932-6203 Institutional support: RVO:61388963 Keywords : retinoic acid biosynthesis * site-directed mutagenesis * tumor marker AKR1B15 Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.234, year: 2014 http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0134506

  8. Applications of Carboxylic Acid Reductases in Oleaginous Microbes

    Energy Technology Data Exchange (ETDEWEB)

    Resch, Michael G.; Linger, Jeffrey; McGeehan, John; Tyo, Keith; Beckham, Gregg

    2016-04-24

    Carboxylic acid reductases (CARs) are recently emerging reductive enzymes for the direct production of aldehydes from biologically-produced carboxylic acids. Recent work has demonstrated that these powerful enzymes are able to reduce a very broad range of volatile- to long-chain fatty acids as well as aromatic acids. Here, we express four CAR enzymes from different fungal origins to test their activity against fatty acids commonly produced in oleaginous microbes. These in vitro results will inform metabolic engineering strategies to conduct mild biological reduction of carboxylic acids in situ, which is conventionally done via hydrotreating catalysis at high temperatures and hydrogen pressures.

  9. Mediated electrochemistry of dimethyl sulfoxide reductase promoted by carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    BERNHARDT; Paul; V

    2010-01-01

    Mediated electrochemistry of dimethyl sulfoxide reductase from Rhodobacter capsulatus (DMSOR) which is immobilized on a bare glassy carbon (GC) electrode and a carbon nanotube (CNT)-modified GC electrode was studied using the Co complex (trans-6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane-6,13-diamine)cobalt(III) ([Co(trans-diammac)] +) as a mediator.The cyclic voltammograms of different electrodes were carried out at different substrate (DMSO) concentrations.The results demonstrated that the catalytic current was increased by employing CNT as a promoter.

  10. Vibrio harveyi Nitroreductase Is Also a Chromate Reductase

    OpenAIRE

    Kwak, Young Hak; Lee, Dong Seok; Kim, Han Bok

    2003-01-01

    The chromate reductase purified from Pseudomonas ambigua was found to be homologous with several nitroreductases. Escherichia coli DH5α and Vibrio harveyi KCTC 2720 nitroreductases were chosen for the present study, and their chromate-reducing activities were determined. A fusion between glutathione S-transferase (GST) and E. coli DH5α NfsA (GST-EcNfsA), a fusion between GST and E. coli DH5α NfsB (GST-EcNfsB), and a fusion between GST and V. harveyi KCTC 2720 NfsA (GST-VhNfsA) were prepared f...

  11. Pulse radiolysis studies on superoxide reductase from Treponema pallidum.

    OpenAIRE

    Nivière, V; Lombard, M.; Fontecave, M.; Houée-Levin, C

    2001-01-01

    Superoxide reductases (SORs) are small metalloenzymes, which catalyze reduction of O2*- to H2O2. The reaction of the enzyme from Treponema pallidum with superoxide was studied by pulse radiolysis methods. The first step is an extremely fast bi-molecular reaction of the ferrous center with O2, with a rate constant of 6 x 10 (8) M(-1) s(-1). A first intermediate is formed which is converted to a second one with a slower rate constant of 4800 s(-1). This latter value is 10 times higher than the ...

  12. Methylenetetrahydrofolate reductase (MTHFR) deficiency presenting as a rash.

    LENUS (Irish Health Repository)

    Crushell, Ellen

    2012-09-01

    We report on the case of a 2-year-old girl recently diagnosed with Methylenetetrahydrofolate reductase (MTHFR) deficiency who originally presented in the neonatal period with a distinctive rash. At 11 weeks of age she developed seizures, she had acquired microcephaly and developmental delay. The rash deteriorated dramatically following commencement of phenobarbitone; both rash and seizures abated following empiric introduction of pyridoxine and folinic acid as treatment of possible vitamin responsive seizures. We postulate that phenobarbitone in combination with MTHFR deficiency may have caused her rash to deteriorate and subsequent folinic acid was helpful in treating the rash and preventing further acute neurological decline as commonly associated with this condition.

  13. Determination of the specific activities of methionine sulfoxide reductase A and B by capillary electrophoresis

    Science.gov (United States)

    A capillary electrophoresis (CE) method for the determination of methionine sulfoxide reductase A and methionine sulfoxide reductase B activities in mouse liver is described. The method is based on detection of the 4-(dimethylamino)azobenzene-4’-sulfonyl derivative of L-methionine (dabsyl Met), the ...

  14. Sucrose mimics the light induction of Arabidopsis nitrate reductase gene transcription

    DEFF Research Database (Denmark)

    Cheng, Chi-Lien; Acedo, Gregoria N; Kristensen, Michael;

    1992-01-01

    Nitrate reductase, the first enzyme in nitrate assimilation, is located at the crossroad of two energy-consuming pathways: nitrate assimilation and carbon fixation. Light, which regulates the expression of many higher-plant carbon fixation genes, also regulates nitrate reductase gene expression. ...

  15. Functions of Flavin Reductase and Quinone Reductase in 2,4,6-Trichlorophenol Degradation by Cupriavidus necator JMP134▿

    OpenAIRE

    Belchik, Sara Mae; Xun, Luying

    2007-01-01

    The tcpRXABCYD operon of Cupriavidus necator JMP134 is involved in the degradation of 2,4,6-trichlorophenol (2,4,6-TCP), a toxic pollutant. TcpA is a reduced flavin adenine dinucleotide (FADH2)-dependent monooxygenase that converts 2,4,6-TCP to 6-chlorohydroxyquinone. It has been implied via genetic analysis that TcpX acts as an FAD reductase to supply TcpA with FADH2, whereas the function of TcpB in 2,4,6-TCP degradation is still unclear. In order to provide direct biochemical evidence for t...

  16. The effect of ionic and non-ionic surfactants on the growth, nitrate reductase and nitrite reductase activities of Spirodela polyrrhiza (L. Schleiden

    Directory of Open Access Journals (Sweden)

    Józef Buczek

    2014-02-01

    Full Text Available Inclusion into the medium of 5 mg•dm-3 of non-ionic (ENF or ionic (DBST surfactant caused 50-60% inhibition of nitrite reductase MR activity in S. polyrrhiza. At the same time, increased accumulation of NO2- in the plant tissues and lowering of the total and soluble protein contents were found. DBST also lowered the nitrate reductase (NR activity and the dry mass of the plants.

  17. Co-Expression of Monodehydroascorbate Reductase and Dehydroascorbate Reductase from Brassica rapa Effectively Confers Tolerance to Freezing-Induced Oxidative Stress

    OpenAIRE

    Shin, Sun-Young; Kim, Myung-Hee; Kim, Yul-Ho; Park, Hyang-Mi; Yoon, Ho-Sung

    2013-01-01

    Plants are exposed to various environmental stresses and have therefore developed antioxidant enzymes and molecules to protect their cellular components against toxicity derived from reactive oxygen species (ROS). Ascorbate is a very important antioxidant molecule in plants, and monodehydroascorbate reductase (MDHAR; EC 1.6.5.4) and dehydroascorbate reductase (DHAR; EC 1.8.5.1) are essential to regeneration of ascorbate for maintenance of ROS scavenging ability. The MDHAR and DHAR genes from ...

  18. Optimisation of nitrate reductase enzyme activity to synthesise silver nanoparticles.

    Science.gov (United States)

    Khodashenas, Bahareh; Ghorbani, Hamid Reza

    2016-06-01

    Today, the synthesis of silver nanoparticles (Ag NPs) is very common since it has many applications in different areas. The synthesis of these nanoparticles is done by means of physical, chemical, or biological methods. However, due to its inexpensive and environmentally friendly features, the biological method is more preferable. In the present study, using nitrate reductase enzyme available in the Escherichia coli (E. coli) bacterium, the biosynthesis of Ag NPs was investigated. In addition, the activity of the nitrate reductase enzyme was optimised by changing its cultural conditions, and the effects of silver nitrate (AgNO3) concentration and enzyme amount on nanoparticles synthesis were studied. Finally, the produced nanoparticles were studied using ultraviolet -visible (UV-Vis) spectrophotometer, dynamic light scattering technique, and transmission electron microscopy. UV-Visible spectrophotometric study showed the characteristic peak for Ag NPs at wavelength 405-420 nm for 1 mM metal precursor solution (AgNO3) with 1, 5, 10, and 20 cc supernatant and 435 nm for 0.01M AgNO3 with 20 cc supernatant. In this study, it was found that there is a direct relationship between the AgNO3 concentration and the size of produced Ag NPs. PMID:27256897

  19. Azotobacter vinelandii NADPH:ferredoxin reductase cloning, sequencing, and overexpression.

    Science.gov (United States)

    Isas, J M; Yannone, S M; Burgess, B K

    1995-09-01

    Azotobacter vinelandii ferredoxin I (AvFdI) controls the expression of another protein that was originally designated Protein X. Recently we reported that Protein X is a NADPH-specific flavoprotein that binds specifically to FdI (Isas, J.M., and Burgess, B.K. (1994) J. Biol. Chem. 269, 19404-19409). The gene encoding this protein has now been cloned and sequenced. Protein X is 33% identical and has an overall 53% similarity with the fpr gene product from Escherichia coli that encodes NADPH:ferredoxin reductase. On the basis of this similarity and the similarity of the physical properties of the two proteins, we now designate Protein X as A. vinelandii NADPH:ferredoxin reductase and its gene as the fpr gene. The protein has been overexpressed in its native background in A. vinelandii by using the broad host range multicopy plasmid, pKT230. In addition to being regulated by FdI, the fpr gene product is overexpressed when A. vinelandii is grown under N2-fixing conditions even though the fpr gene is not preceded by a nif specific promoter. By analogy to what is known about fpr expression in E. coli, we propose that FdI may exert its regulatory effect on fpr by interacting with the SoxRS regulon. PMID:7673160

  20. Nitrate metabolism in tobacco leaves overexpressing Arabidopsis nitrite reductase.

    Science.gov (United States)

    Davenport, Susie; Le Lay, Pascaline; Sanchez-Tamburrrino, Juan Pablo

    2015-12-01

    Primary nitrogen assimilation in plants includes the reduction of nitrite to ammonium in the chloroplasts by the enzyme nitrite reductase (NiR EC:1.7.7.1) or in the plastids of non-photosynthetic organs. Here we report on a study overexpressing the Arabidopsis thaliana NiR (AtNiR) gene in tobacco plants under the control of a constitutive promoter (CERV - Carnation Etched Ring Virus). The aim was to overexpress AtNiR in an attempt to alter the level of residual nitrite in the leaf which can act as precursor to the formation of nitrosamines. The impact of increasing the activity of AtNiR produced an increase in leaf protein and a stay-green phenotype in the primary transformed AtNiR population. Investigation of the T1 homozygous population demonstrated elevated nitrate reductase (NR) activity, reductions in leaf nitrite and nitrate and the amino acids proline, glutamine and glutamate. Chlorophyl content of the transgenic lines was increased, as evidenced by the stay-green phenotype. This reveals the importance of NiR in primary nitrogen assimilation and how modification of this key enzyme affects both the nitrogen and carbon metabolism of tobacco plants. PMID:26447683

  1. Pinpointing a Mechanistic Switch Between Ketoreduction and "Ene" Reduction in Short-Chain Dehydrogenases/Reductases.

    Science.gov (United States)

    Lygidakis, Antonios; Karuppiah, Vijaykumar; Hoeven, Robin; Ní Cheallaigh, Aisling; Leys, David; Gardiner, John M; Toogood, Helen S; Scrutton, Nigel S

    2016-08-01

    Three enzymes of the Mentha essential oil biosynthetic pathway are highly homologous, namely the ketoreductases (-)-menthone:(-)-menthol reductase and (-)-menthone:(+)-neomenthol reductase, and the "ene" reductase isopiperitenone reductase. We identified a rare catalytic residue substitution in the last two, and performed comparative crystal structure analyses and residue-swapping mutagenesis to investigate whether this determines the reaction outcome. The result was a complete loss of native activity and a switch between ene reduction and ketoreduction. This suggests the importance of a catalytic glutamate vs. tyrosine residue in determining the outcome of the reduction of α,β-unsaturated alkenes, due to the substrate occupying different binding conformations, and possibly also to the relative acidities of the two residues. This simple switch in mechanism by a single amino acid substitution could potentially generate a large number of de novo ene reductases. PMID:27411040

  2. Low toxicity corrosion inhibitors

    International Nuclear Information System (INIS)

    This paper discusses the design and testing of low toxicity corrosion inhibitors. New chemistries have been investigated with respect to corrosion protection and impact on the marine environment. The resulting chemicals, while they are effective corrosion inhibitors, present significant improvements in terms of environmental properties over current products. The discussion includes results of the corrosion inhibition, toxicity, biodegradability and partitioning studies

  3. Structure of the Francisella tularensis enoyl-acyl carrier protein reductase (FabI) in complex with NAD[superscript +] and triclosan

    Energy Technology Data Exchange (ETDEWEB)

    Mehboob, Shahila; Truong, Kent; Santarsiero, Bernard D.; Johnson, Michael E. (UIC)

    2010-11-19

    Enoyl-acyl carrier protein reductase (FabI) catalyzes the last rate-limiting step in the elongation cycle of the fatty-acid biosynthesis pathway and has been validated as a potential antimicrobial drug target in Francisella tularensis. The development of new antibiotic therapies is important both to combat potential drug-resistant bioweapons and to address the broader societal problem of increasing antibiotic resistance among many pathogenic bacteria. The crystal structure of FabI from F. tularensis (FtuFabI) in complex with the inhibitor triclosan and the cofactor NAD{sup +} has been solved to a resolution of 2.1 {angstrom}. Triclosan is known to effectively inhibit FabI from different organisms. Precise characterization of the mode of triclosan binding is required to develop highly specific inhibitors. Comparison of our structure with the previously determined FtuFabI structure (PDB code 2jjy) which is bound to only NAD{sup +} reveals the conformation of the substrate-binding loop, electron density for which was missing in the earlier structure, and demonstrates a shift in the conformation of the NAD{sup +} cofactor. This shift in the position of the phosphate groups allows more room in the active site for substrate or inhibitor to bind and be better accommodated. This information will be crucial for virtual screening studies to identify novel scaffolds for development into new active inhibitors.

  4. Functional complementation of a nitrate reductase defective mutant of a green alga Dunaliella viridis by introducing the nitrate reductase gene.

    Science.gov (United States)

    Sun, Yu; Gao, Xiaoshu; Li, Qiyun; Zhang, Qingqi; Xu, Zhengkai

    2006-08-01

    Nitrate reductase (NR) catalyzes NAD (P) H dependent reduction of nitrate to nitrite. Transformation systems have been established in several species of green algae by nitrate reductase gene functional complementation. In this report, an endogenous NR cDNA (3.4 kb) and a genomic fragment (14.6 kb) containing the NR gene (DvNIA1) were isolated from the D. viridis cDNA and genomic libraries respectively. Southern blot and Northern blot analyses showed that this gene exists as a single copy in D. viridis and is induced by nitrate. To obtain a NR defective mutant as a recipient strain, D. viridis cells were treated with a chemical mutagen and then cultured on a chlorate-containing plate to enrich chlorate tolerant mutants. Southern analysis showed that one isolate, B14, had a deletion in the DvNIA1 gene region. Using electroporation conditions determined in this laboratory, plasmid pDVNR containing the intact DvNIA1 gene has been electroporated into the defective mutant B14. Strains retaining a nitrate assimilation phenotype were obtained from nitrate plates after spreading the electroporated cells. In some individual strains, transcription of the introduced gene was detected. NR activity in these strains was slightly higher than that in the defective B14 cell, but excretion of nitrite into culture media was almost as high as that of the wild-type cell. Possible episomal presence of the introduced DNA in D. viridis is discussed. PMID:16797881

  5. Dimerization and enzymatic activity of fungal 17β-hydroxysteroid dehydrogenase from the short-chain dehydrogenase/reductase superfamily

    Directory of Open Access Journals (Sweden)

    Kristan Katja

    2005-12-01

    Full Text Available Abstract Background 17β-hydroxysteroid dehydrogenase from the fungus Cochliobolus lunatus (17β-HSDcl is a member of the short-chain dehydrogenase/reductase (SDR superfamily. SDR proteins usually function as dimers or tetramers and 17β-HSDcl is also a homodimer under native conditions. Results We have investigated here which secondary structure elements are involved in the dimerization of 17β-HSDcl and examined the importance of dimerization for the enzyme activity. Sequence similarity with trihydroxynaphthalene reductase from Magnaporthe grisea indicated that Arg129 and His111 from the αE-helices interact with the Asp121, Glu117 and Asp187 residues from the αE and αF-helices of the neighbouring subunit. The Arg129Asp and His111Leu mutations both rendered 17β-HSDcl monomeric, while the mutant 17β-HSDcl-His111Ala was dimeric. Circular dichroism spectroscopy analysis confirmed the conservation of the secondary structure in both monomers. The three mutant proteins all bound coenzyme, as shown by fluorescence quenching in the presence of NADP+, but both monomers showed no enzymatic activity. Conclusion We have shown by site-directed mutagenesis and structure/function analysis that 17β-HSDcl dimerization involves the αE and αF helices of both subunits. Neighbouring subunits are connected through hydrophobic interactions, H-bonds and salt bridges involving amino acid residues His111 and Arg129. Since the substitutions of these two amino acid residues lead to inactive monomers with conserved secondary structure, we suggest dimerization is a prerequisite for catalysis. A detailed understanding of this dimerization could lead to the development of compounds that will specifically prevent dimerization, thereby serving as a new type of inhibitor.

  6. Vibrio harveyi Nitroreductase Is Also a Chromate Reductase

    Science.gov (United States)

    Kwak, Young Hak; Lee, Dong Seok; Kim, Han Bok

    2003-01-01

    The chromate reductase purified from Pseudomonas ambigua was found to be homologous with several nitroreductases. Escherichia coli DH5α and Vibrio harveyi KCTC 2720 nitroreductases were chosen for the present study, and their chromate-reducing activities were determined. A fusion between glutathione S-transferase (GST) and E. coli DH5α NfsA (GST-EcNfsA), a fusion between GST and E. coli DH5α NfsB (GST-EcNfsB), and a fusion between GST and V. harveyi KCTC 2720 NfsA (GST-VhNfsA) were prepared for their overproduction and easy purification. GST-EcNfsA, GST-EcNFsB, and GST-VhNFsA efficiently reduced nitrofurazone and 2,4,6-trinitrotoluene (TNT) as their nitro substrates. The Km values for GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA for chromate reduction were 11.8, 23.5, and 5.4 μM, respectively. The Vmax values for GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA were 3.8, 3.9, and 10.7 nmol/min/mg of protein, respectively. GST-VhNfsA was the most effective of the three chromate reductases, as determined by each Vmax/Km value. The optimal temperatures of GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA for chromate reduction were 55, 30, and 30°C, respectively. Thus, it is confirmed that nitroreductase can also act as a chromate reductase. Nitroreductases may be used in chromate remediation. GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA have a molecular mass of 50 kDa and exist as a monomer in solution. Thin-layer chromatography showed that GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA contain FMN as a cofactor. GST-VhNfsA reduced Cr(VI) to Cr(III). Cr(III) was much less toxic to E. coli than Cr(VI). PMID:12902220

  7. Interaction Energy Analysis of Nonclassical Antifolates with Pneumocystis carinii Dihydrofolate Reductase

    Directory of Open Access Journals (Sweden)

    William M. Southerland

    2002-11-01

    Full Text Available Abstract: The x-ray structure of the Pneumocystis carinii dihydrofolate reductase (DHFR:trimethoprim:NADPH ternary complex obtained from the Protein Databank was used as a structural template to generate models for the following complexes: P. carinii DHFR:piritrexim:NADPH, P. carinii DHFR:epiroprim:NADPH, and P. carinii DHFR:trimetrexate:NADPH. Each of these complexes, including the original trimethoprim complex was then modeled in 60 angstrom cubes of explicit water and minimized to a rms gradient between 1.0 to 3.0 x 10-5 kcal/angstrom. Subsequently, each antifolate structure was subdivided into distinct substructural regions. The minimized complexes were used to calculate interaction energies for each intact antifolate and its corresponding substructural regions with the P. carinii DHFR binding site residues, the DHFR protein, the solvated complex ( which consists of P. carinii DHFR, NADPH, and solvent water, solvent water alone, and NADPH. Antifolate substructural regions which contained nitrogen and carbon atoms in an aromatic environment (i. e. the pteridyl, pyridopyrimidinyl, and diaminopyrimidinyl subregions contributed most to the stability of antifolate interactions, while interaction energies for the hydrocarbon aromatic rings, methoxy, and ethoxy groups were much less stable. Additionally, interaction energy analyses were calculated for carbon and nitrogen atoms of the pteridyl, pyridopyrimidinyl, and diaminopyrimidinyl subregions and for the carbon and oxygen atoms of methoxy and ethoxy subregions. The contributions of hydrogen atoms were included with those of the carbon, nitrogen and oxygen atoms to which they are attached. These analyses revealed that the carbon atoms of the pteridyl, pyridopyrimidinyl, and diaminopyrimidinyl subregions generally contributed most to the stability of those regions. Carbon atoms also contributed favorably to the stability of the methoxy group interactions. Those substructural regions which exhibit

  8. Structure determination and functional analysis of a chromate reductase from Gluconacetobacter hansenii.

    Directory of Open Access Journals (Sweden)

    Hongjun Jin

    Full Text Available Environmental protection through biological mechanisms that aid in the reductive immobilization of toxic metals (e.g., chromate and uranyl has been identified to involve specific NADH-dependent flavoproteins that promote cell viability. To understand the enzyme mechanisms responsible for metal reduction, the enzyme kinetics of a putative chromate reductase from Gluconacetobacter hansenii (Gh-ChrR was measured and the crystal structure of the protein determined at 2.25 Å resolution. Gh-ChrR catalyzes the NADH-dependent reduction of chromate, ferricyanide, and uranyl anions under aerobic conditions. Kinetic measurements indicate that NADH acts as a substrate inhibitor; catalysis requires chromate binding prior to NADH association. The crystal structure of Gh-ChrR shows the protein is a homotetramer with one bound flavin mononucleotide (FMN per subunit. A bound anion is visualized proximal to the FMN at the interface between adjacent subunits within a cationic pocket, which is positioned at an optimal distance for hydride transfer. Site-directed substitutions of residues proposed to involve in both NADH and metal anion binding (N85A or R101A result in 90-95% reductions in enzyme efficiencies for NADH-dependent chromate reduction. In comparison site-directed substitution of a residue (S118A participating in the coordination of FMN in the active site results in only modest (50% reductions in catalytic efficiencies, consistent with the presence of a multitude of side chains that position the FMN in the active site. The proposed proximity relationships between metal anion binding site and enzyme cofactors is discussed in terms of rational design principles for the use of enzymes in chromate and uranyl bioremediation.

  9. Comparative induction of nitrate reductase by nitrate and nitrite in barley leaves

    Science.gov (United States)

    Aslam, M.; Rosichan, J. L.; Huffaker, R. C.

    1987-01-01

    The comparative induction of nitrate reductase (NR) by ambient NO3- and NO2- as a function of influx, reduction (as NR was induced) and accumulation in detached leaves of 8-day-old barley (Hordeum vulgare L.) seedlings was determined. The dynamic interaction of NO3- influx, reduction and accumulation on NR induction was shown. The activity of NR, as it was induced, influenced its further induction by affecting the internal concentration of NO3-. As the ambient concentration of NO3- increased, the relative influences imposed by influx and reduction on NO3- accumulation changed with influx becoming a more predominant regulant. Significant levels of NO3- accumulated in NO2(-)-fed leaves. When the leaves were supplied cycloheximide or tungstate along with NO2-, about 60% more NO3- accumulated in the leaves than in the absence of the inhibitors. In NO3(-)-supplied leaves NR induction was observed at an ambient concentration of as low as 0.02 mM. No NR induction occurred in leaves supplied with NO2- until the ambient NO2- concentration was 0.5 mM. In fact, NR induction from NO2- solutions was not seen until NO3- was detected in the leaves. The amount of NO3- accumulating in NO2(-)-fed leaves induced similar levels of NR as did equivalent amounts of NO3- accumulating from NO3(-)-fed leaves. In all cases the internal concentration of NO3-, but not NO2-, was highly correlated with the amount of NR induced. The evidence indicated that NO3- was a more likely inducer of NR than was NO2-.

  10. A multiscale, mechanism-driven, dynamic model for the effects of 5α-reductase inhibition on prostate maintenance.

    Science.gov (United States)

    Zager, Michael G; Barton, Hugh A

    2012-01-01

    A systems-level mathematical model is presented that describes the effects of inhibiting the enzyme 5α-reductase (5aR) on the ventral prostate of the adult male rat under chronic administration of the 5aR inhibitor, finasteride. 5aR is essential for androgen regulation in males, both in normal conditions and disease states. The hormone kinetics and downstream effects on reproductive organs associated with perturbing androgen regulation are complex and not necessarily intuitive. Inhibition of 5aR decreases the metabolism of testosterone (T) to the potent androgen 5α-dihydrotestosterone (DHT). This results in decreased cell proliferation, fluid production and 5aR expression as well as increased apoptosis in the ventral prostate. These regulatory changes collectively result in decreased prostate size and function, which can be beneficial to men suffering from benign prostatic hyperplasia (BPH) and could play a role in prostate cancer. There are two distinct isoforms of 5aR in male humans and rats, and thus developing a 5aR inhibitor is a challenging pursuit. Several inhibitors are on the market for treatment of BPH, including finasteride and dutasteride. In this effort, comparisons of simulated vs. experimental T and DHT levels and prostate size are depicted, demonstrating the model accurately described an approximate 77% decrease in prostate size and nearly complete depletion of prostatic DHT following 21 days of daily finasteride dosing in rats. This implies T alone is not capable of maintaining a normal prostate size. Further model analysis suggests the possibility of alternative dosing strategies resulting in similar or greater effects on prostate size, due to complex kinetics between T, DHT and gene occupancy. With appropriate scaling and parameterization for humans, this model provides a multiscale modeling platform for drug discovery teams to test and generate hypotheses about drugging strategies for indications like BPH and prostate cancer, such as compound

  11. A multiscale, mechanism-driven, dynamic model for the effects of 5α-reductase inhibition on prostate maintenance.

    Directory of Open Access Journals (Sweden)

    Michael G Zager

    Full Text Available A systems-level mathematical model is presented that describes the effects of inhibiting the enzyme 5α-reductase (5aR on the ventral prostate of the adult male rat under chronic administration of the 5aR inhibitor, finasteride. 5aR is essential for androgen regulation in males, both in normal conditions and disease states. The hormone kinetics and downstream effects on reproductive organs associated with perturbing androgen regulation are complex and not necessarily intuitive. Inhibition of 5aR decreases the metabolism of testosterone (T to the potent androgen 5α-dihydrotestosterone (DHT. This results in decreased cell proliferation, fluid production and 5aR expression as well as increased apoptosis in the ventral prostate. These regulatory changes collectively result in decreased prostate size and function, which can be beneficial to men suffering from benign prostatic hyperplasia (BPH and could play a role in prostate cancer. There are two distinct isoforms of 5aR in male humans and rats, and thus developing a 5aR inhibitor is a challenging pursuit. Several inhibitors are on the market for treatment of BPH, including finasteride and dutasteride. In this effort, comparisons of simulated vs. experimental T and DHT levels and prostate size are depicted, demonstrating the model accurately described an approximate 77% decrease in prostate size and nearly complete depletion of prostatic DHT following 21 days of daily finasteride dosing in rats. This implies T alone is not capable of maintaining a normal prostate size. Further model analysis suggests the possibility of alternative dosing strategies resulting in similar or greater effects on prostate size, due to complex kinetics between T, DHT and gene occupancy. With appropriate scaling and parameterization for humans, this model provides a multiscale modeling platform for drug discovery teams to test and generate hypotheses about drugging strategies for indications like BPH and prostate cancer

  12. Studies of Toxoplasma gondii and Plasmodium falciparum enoyl acyl carrier protein reductase and implications for the development of antiparasitic agents

    Energy Technology Data Exchange (ETDEWEB)

    Muench, Stephen P. [The Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN (United Kingdom); Prigge, Sean T. [Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205 (United States); McLeod, Rima [Department of Ophthalmology and Visual Sciences, Paediatrics (Infectious Diseases) and Pathology and the Committees on Molecular Medicine, Genetics, Immunology and The College, The University of Chicago, Chicago, IL 60637 (United States); Rafferty, John B. [The Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN (United Kingdom); Kirisits, Michael J. [Department of Ophthalmology and Visual Sciences, Paediatrics (Infectious Diseases) and Pathology and the Committees on Molecular Medicine, Genetics, Immunology and The College, The University of Chicago, Chicago, IL 60637 (United States); Roberts, Craig W. [Department of Immunology, University of Strathclyde, Glasgow G4 0NR, Scotland (United Kingdom); Mui, Ernest J. [Department of Ophthalmology and Visual Sciences, Paediatrics (Infectious Diseases) and Pathology and the Committees on Molecular Medicine, Genetics, Immunology and The College, The University of Chicago, Chicago, IL 60637 (United States); Rice, David W., E-mail: d.rice@sheffield.ac.uk [The Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN (United Kingdom)

    2007-03-01

    The crystal structures of T. gondii and P. falciparum ENR in complex with NAD{sup +} and triclosan and of T. gondii ENR in an apo form have been solved to 2.6, 2.2 and 2.8 Å, respectively. Recent studies have demonstrated that submicromolar concentrations of the biocide triclosan arrest the growth of the apicomplexan parasites Plasmodium falciparum and Toxoplasma gondii and inhibit the activity of the apicomplexan enoyl acyl carrier protein reductase (ENR). The crystal structures of T. gondii and P. falciparum ENR in complex with NAD{sup +} and triclosan and of T. gondii ENR in an apo form have been solved to 2.6, 2.2 and 2.8 Å, respectively. The structures of T. gondii ENR have revealed that, as in its bacterial and plant homologues, a loop region which flanks the active site becomes ordered upon inhibitor binding, resulting in the slow tight binding of triclosan. In addition, the T. gondii ENR–triclosan complex reveals the folding of a hydrophilic insert common to the apicomplexan family that flanks the substrate-binding domain and is disordered in all other reported apicomplexan ENR structures. Structural comparison of the apicomplexan ENR structures with their bacterial and plant counterparts has revealed that although the active sites of the parasite enzymes are broadly similar to those of their bacterial counterparts, there are a number of important differences within the drug-binding pocket that reduce the packing interactions formed with several inhibitors in the apicomplexan ENR enzymes. Together with other significant structural differences, this provides a possible explanation of the lower affinity of the parasite ENR enzyme family for aminopyridine-based inhibitors, suggesting that an effective antiparasitic agent may well be distinct from equivalent antimicrobials.

  13. Studies of Toxoplasma gondii and Plasmodium falciparum enoyl acyl carrier protein reductase and implications for the development of antiparasitic agents

    International Nuclear Information System (INIS)

    The crystal structures of T. gondii and P. falciparum ENR in complex with NAD+ and triclosan and of T. gondii ENR in an apo form have been solved to 2.6, 2.2 and 2.8 Å, respectively. Recent studies have demonstrated that submicromolar concentrations of the biocide triclosan arrest the growth of the apicomplexan parasites Plasmodium falciparum and Toxoplasma gondii and inhibit the activity of the apicomplexan enoyl acyl carrier protein reductase (ENR). The crystal structures of T. gondii and P. falciparum ENR in complex with NAD+ and triclosan and of T. gondii ENR in an apo form have been solved to 2.6, 2.2 and 2.8 Å, respectively. The structures of T. gondii ENR have revealed that, as in its bacterial and plant homologues, a loop region which flanks the active site becomes ordered upon inhibitor binding, resulting in the slow tight binding of triclosan. In addition, the T. gondii ENR–triclosan complex reveals the folding of a hydrophilic insert common to the apicomplexan family that flanks the substrate-binding domain and is disordered in all other reported apicomplexan ENR structures. Structural comparison of the apicomplexan ENR structures with their bacterial and plant counterparts has revealed that although the active sites of the parasite enzymes are broadly similar to those of their bacterial counterparts, there are a number of important differences within the drug-binding pocket that reduce the packing interactions formed with several inhibitors in the apicomplexan ENR enzymes. Together with other significant structural differences, this provides a possible explanation of the lower affinity of the parasite ENR enzyme family for aminopyridine-based inhibitors, suggesting that an effective antiparasitic agent may well be distinct from equivalent antimicrobials

  14. Aspects of Ribonucleotide Reductase Regulation and Genome Stability

    DEFF Research Database (Denmark)

    Nielsen, Helena Berner Nedergaard

    In all living cells, synthesis of the DNA building blocks, deoxyribonucleoside triphosphates (dNTPs), is tightly regulated to ensure a precise DNA replication to maintain genomic stability. Ribonucleotide reductase (RNR) is the enzyme responsible for reducing ribonucleotides to their deoxy forms....... RNR consists of two subunits: R1 and R2, both of which are essential. The activity of RNR is strictly regulated to control the dNTP pool, both by allosteric feedback control and transcriptional and translational controls. Four inhibitory proteins of RNR have been identified in yeast: Spd1 in fission...... yeast, and Sml1, Hug1, and Dif1 in budding yeast. An elevated, as well as a reduced dNTP pool is shown to lead to an increase in spontaneous mutation rates, hence regulation of RNR is very important in order to maintain genomic stability. No human inhibitory proteins have yet been identified to regulate...

  15. Two methylenetetrahydrofolate reductase gene (MTHFR) polymorphisms, schizophrenia and bipolar disorder

    DEFF Research Database (Denmark)

    Jönsson, Erik G; Larsson, Kristina; Vares, Maria;

    2008-01-01

    disorder. In a replication attempt the MTHFR C677T and A1298C SNPs were analyzed in three Scandinavian schizophrenia case-control samples. In addition, Norwegian patients with bipolar disorder were investigated. There were no statistically significant allele or genotype case-control differences. The...... present Scandinavian results do not verify previous associations between the putative functional MTHFR gene polymorphisms and schizophrenia or bipolar disorder. However, when combined with previous studies in meta-analyses there is still evidence for association between the MTHFR C677T polymorphism and......Recent meta-analyses of the methylenetetrahydrofolate reductase gene (MTHFR) have suggested association between two of its functional single gene polymorphisms (SNPs; C677T and A1298C) and schizophrenia. Studies have also suggested association between MTHFR C677T and A1298C variation and bipolar...

  16. Crystal structure of isoflavone reductase from alfalfa (Medicago sativa L.).

    Science.gov (United States)

    Wang, Xiaoqiang; He, Xianzhi; Lin, Jianqiao; Shao, Hui; Chang, Zhenzhan; Dixon, Richard A

    2006-05-19

    Isoflavonoids play important roles in plant defense and exhibit a range of mammalian health-promoting activities. Isoflavone reductase (IFR) specifically recognizes isoflavones and catalyzes a stereospecific NADPH-dependent reduction to (3R)-isoflavanone. The crystal structure of Medicago sativa IFR with deletion of residues 39-47 has been determined at 1.6A resolution. Structural analysis, molecular modeling and docking, and comparison with the structures of other NADPH-dependent enzymes, defined the putative binding sites for co-factor and substrate and potential key residues for enzyme activity and substrate specificity. Further mutagenesis has confirmed the role of Lys144 as a catalytic residue. This study provides a structural basis for understanding the enzymatic mechanism and substrate specificity of IFRs as well as the functions of IFR-like proteins. PMID:16600295

  17. Pulse radiolysis studies on superoxide reductase from Treponema pallidum

    CERN Document Server

    Nivière, V; Fontecave, M; Houée-Levin, C

    2015-01-01

    Superoxide reductases (SORs) are small metalloenzymes, which catalyze reduction of O2*- to H2O2. The reaction of the enzyme from Treponema pallidum with superoxide was studied by pulse radiolysis methods. The first step is an extremely fast bi-molecular reaction of the ferrous center with O2, with a rate constant of 6 x 10 (8) M(-1) s(-1). A first intermediate is formed which is converted to a second one with a slower rate constant of 4800 s(-1). This latter value is 10 times higher than the corresponding one previously reported in the case of SOR from Desulfoarculus baarsii. The reconstituted spectra for the two intermediates are consistent with formation of transient iron-peroxide species.

  18. Two methylenetetrahydrofolate reductase gene (MTHFR) polymorphisms, schizophrenia and bipolar disorder

    DEFF Research Database (Denmark)

    Jönsson, Erik G; Larsson, Kristina; Vares, Maria; Hansen, Thomas; Wang, August G; Djurovic, Srdjan; Rønningen, Kjersti S; Andreassen, Ole A; Agartz, Ingrid; Werge, Thomas; Terenius, Lars; Hall, Håkan

    disorder. In a replication attempt the MTHFR C677T and A1298C SNPs were analyzed in three Scandinavian schizophrenia case-control samples. In addition, Norwegian patients with bipolar disorder were investigated. There were no statistically significant allele or genotype case-control differences. The...... present Scandinavian results do not verify previous associations between the putative functional MTHFR gene polymorphisms and schizophrenia or bipolar disorder. However, when combined with previous studies in meta-analyses there is still evidence for association between the MTHFR C677T polymorphism and......Recent meta-analyses of the methylenetetrahydrofolate reductase gene (MTHFR) have suggested association between two of its functional single gene polymorphisms (SNPs; C677T and A1298C) and schizophrenia. Studies have also suggested association between MTHFR C677T and A1298C variation and bipolar...

  19. Two isosteric fluorinated derivatives of the powerful glucosidase inhibitors1-deoxynojirimycin and 2,5-dideoxy-2,5-imino-D-mannitol: Syntheses and glycosidase-inhibitory activities of 1,2,5-trideoxy-2-fluoro-1,5-imino-D-glucitol and of 1,2,5-trideoxy-1-fluoro-2,5-imino-D-mannitol

    DEFF Research Database (Denmark)

    Andersen, Søren Møller; Ebner, Michael; Ekhart, Christian W.; Gradnig, Günther; Legler, Günther; Lundt, Inge; Stütz, A.E.; Withers, S.G.; Wrodnigg, T.

    1,2,5-trideoxy-2-fluoro-1,5-imino-D-glucitol, the 2-deoxyfluoro derivative of 1-deoxynojirimycin, as well as 1,2,5-trideoxy-1-fluoro-2,5-imino-D-mannitol and 2,5-dideoxy-2,5-imino-1-O-methyl-D-mannitol, two new analogues of the natural product and powerful glucosidase inhibitor 2,5-dideoxy-2......,5-imino-D-mannitol, were synthesised featuring glucose isomerase-catalysed aldose-ketose interconvertion reactions as the key steps of the syntheses.Results of inhibition studies conducted with these compounds and previously obtained deoxyfluoro derivatives of 1-deoxynojirimycin, employing glucosidases...... from various sources, showed that the replacement of a hydroxyl function by fluorine caused an impairment of the inhibitory potency. This effect was smallest for the hydroxyl group at C-6 and up to four orders of magnitude larger for replacements at C-2 and C-3....

  20. Isolation and characterization of nitric oxide reductase from Paracoccus halodenitrificans.

    Science.gov (United States)

    Sakurai, N; Sakurai, T

    1997-11-11

    Nitric oxide reductase was isolated from the membrane fraction of a denitrifying bacterium, Paracoccus halodenitrificans, in the presence of n-dodecyl beta-D-maltoside. A relatively simple and effective procedure to purify NO reductase using DEAE-Toyopearl and hydroxyapatite (ceramic) chromatographies has been developed. The enzyme consisted of two subunits with molecular masses of 20 and 42 kDa associated with the c-type heme and two b-type hemes, respectively. The optical and magnetic circular dichroism (MCD) spectra of the oxidized (as isolated) and reduced enzymes indicated that the heme c is in the low-spin state and the hemes b are in the high- and low-spin states. The EPR spectrum also showed the presence of the split high-spin component (g perpendicular = 6.6, 6.0) and two low spin components (gz,y,x = 2.96, 2.26, 1.46, gz = 3.59). Although the presence of an extra iron was suggested from atomic absorption spectroscopy, a non-heme iron could not be detected by colorimetric titrations using ferene and 2-(5-nitro-2-pyridylazo)- 5-(N-propyl-N-sulfopropylamino)phenolate (PAPS). One of the extra signals at g = 4.3 and 2.00 might come from a non-heme iron, while they may originate from an adventitious iron and a certain nonmetallic radical, respectively. When CO acted on the reduced enzyme, both of the low-spin hemes were not affected, and when NO acted on the reduced enzyme, the optical and MCD spectra were of a mixture of the oxidized and reduced enzymes. Consequently, the reduction of NO was supposed to take place at the high-spin heme b. The heme c and the low-spin heme b centers were considered to function as electron mediators during the intermolecular and intramolecular processes. PMID:9374857

  1. Identification of imine reductase-specific sequence motifs.

    Science.gov (United States)

    Fademrecht, Silvia; Scheller, Philipp N; Nestl, Bettina M; Hauer, Bernhard; Pleiss, Jürgen

    2016-05-01

    Chiral amines are valuable building blocks for the production of a variety of pharmaceuticals, agrochemicals and other specialty chemicals. Only recently, imine reductases (IREDs) were discovered which catalyze the stereoselective reduction of imines to chiral amines. Although several IREDs were biochemically characterized in the last few years, knowledge of the reaction mechanism and the molecular basis of substrate specificity and stereoselectivity is limited. To gain further insights into the sequence-function relationships, the Imine Reductase Engineering Database (www.IRED.BioCatNet.de) was established and a systematic analysis of 530 putative IREDs was performed. A standard numbering scheme based on R-IRED-Sk was introduced to facilitate the identification and communication of structurally equivalent positions in different proteins. A conservation analysis revealed a highly conserved cofactor binding region and a predominantly hydrophobic substrate binding cleft. Two IRED-specific motifs were identified, the cofactor binding motif GLGxMGx5 [ATS]x4 Gx4 [VIL]WNR[TS]x2 [KR] and the active site motif Gx[DE]x[GDA]x[APS]x3 {K}x[ASL]x[LMVIAG]. Our results indicate a preference toward NADPH for all IREDs and explain why, despite their sequence similarity to β-hydroxyacid dehydrogenases (β-HADs), no conversion of β-hydroxyacids has been observed. Superfamily-specific conservations were investigated to explore the molecular basis of their stereopreference. Based on our analysis and previous experimental results on IRED mutants, an exclusive role of standard position 187 for stereoselectivity is excluded. Alternatively, two standard positions 139 and 194 were identified which are superfamily-specifically conserved and differ in R- and S-selective enzymes. Proteins 2016; 84:600-610. © 2016 Wiley Periodicals, Inc. PMID:26857686

  2. Fatty acyl-CoA reductases of birds

    Directory of Open Access Journals (Sweden)

    Hellenbrand Janine

    2011-12-01

    Full Text Available Abstract Background Birds clean and lubricate their feathers with waxes that are produced in the uropygial gland, a holocrine gland located on their back above the tail. The type and the composition of the secreted wax esters are dependent on the bird species, for instance the wax ester secretion of goose contains branched-chain fatty acids and unbranched fatty alcohols, whereas that of barn owl contains fatty acids and alcohols both of which are branched. Alcohol-forming fatty acyl-CoA reductases (FAR catalyze the reduction of activated acyl groups to fatty alcohols that can be esterified with acyl-CoA thioesters forming wax esters. Results cDNA sequences encoding fatty acyl-CoA reductases were cloned from the uropygial glands of barn owl (Tyto alba, domestic chicken (Gallus gallus domesticus and domestic goose (Anser anser domesticus. Heterologous expression in Saccharomyces cerevisiae showed that they encode membrane associated enzymes which catalyze a NADPH dependent reduction of acyl-CoA thioesters to fatty alcohols. By feeding studies of transgenic yeast cultures and in vitro enzyme assays with membrane fractions of transgenic yeast cells two groups of isozymes with different properties were identified, termed FAR1 and FAR2. The FAR1 group mainly synthesized 1-hexadecanol and accepted substrates in the range between 14 and 18 carbon atoms, whereas the FAR2 group preferred stearoyl-CoA and accepted substrates between 16 and 20 carbon atoms. Expression studies with tissues of domestic chicken indicated that FAR transcripts were not restricted to the uropygial gland. Conclusion The data of our study suggest that the identified and characterized avian FAR isozymes, FAR1 and FAR2, can be involved in wax ester biosynthesis and in other pathways like ether lipid synthesis.

  3. Evidence for a hexaheteromeric methylenetetrahydrofolate reductase in Moorella thermoacetica.

    Science.gov (United States)

    Mock, Johanna; Wang, Shuning; Huang, Haiyan; Kahnt, Jörg; Thauer, Rudolf K

    2014-09-01

    Moorella thermoacetica can grow with H₂ and CO₂, forming acetic acid from 2 CO₂ via the Wood-Ljungdahl pathway. All enzymes involved in this pathway have been characterized to date, except for methylenetetrahydrofolate reductase (MetF). We report here that the M. thermoacetica gene that putatively encodes this enzyme, metF, is part of a transcription unit also containing the genes hdrCBA, mvhD, and metV. MetF copurified with the other five proteins encoded in the unit in a hexaheteromeric complex with an apparent molecular mass in the 320-kDa range. The 40-fold-enriched preparation contained per mg protein 3.1 nmol flavin adenine dinucleotide (FAD), 3.4 nmol flavin mononucleotide (FMN), and 110 nmol iron, almost as predicted from the primary structure of the six subunits. It catalyzed the reduction of methylenetetrahydrofolate with reduced benzyl viologen but not with NAD(P)H in either the absence or presence of oxidized ferredoxin. It also catalyzed the reversible reduction of benzyl viologen with NADH (diaphorase activity). Heterologous expression of the metF gene in Escherichia coli revealed that the subunit MetF contains one FMN rather than FAD. MetF exhibited 70-fold-higher methylenetetrahydrofolate reductase activity with benzyl viologen when produced together with MetV, which in part shows sequence similarity to MetF. Heterologously produced HdrA contained 2 FADs and had NAD-specific diaphorase activity. Our results suggested that the physiological electron donor for methylenetetrahydrofolate reduction in M. thermoacetica is NADH and that the exergonic reduction of methylenetetrahydrofolate with NADH is coupled via flavin-based electron bifurcation with the endergonic reduction of an electron acceptor, whose identity remains unknown. PMID:25002540

  4. Nitrite and nitrous oxide reductase regulation by nitrogen oxides in Rhodobacter sphaeroides f. sp. denitrificans IL106.

    Science.gov (United States)

    Sabaty, M; Schwintner, C; Cahors, S; Richaud, P; Verméglio, A

    1999-10-01

    We have cloned the nap locus encoding the periplasmic nitrate reductase in Rhodobacter sphaeroides f. sp. denitrificans IL106. A mutant with this enzyme deleted is unable to grow under denitrifying conditions. Biochemical analysis of this mutant shows that in contrast to the wild-type strain, the level of synthesis of the nitrite and N(2)O reductases is not increased by the addition of nitrate. Growth under denitrifying conditions and induction of N oxide reductase synthesis are both restored by the presence of a plasmid containing the genes encoding the nitrate reductase. This demonstrates that R. sphaeroides f. sp. denitrificans IL106 does not possess an efficient membrane-bound nitrate reductase and that nitrate is not the direct inducer for the nitrite and N(2)O reductases in this species. In contrast, we show that nitrite induces the synthesis of the nitrate reductase. PMID:10498715

  5. Characterization and regulation of Leishmania major 3-hydroxy-3-methylglutaryl-CoA reductase

    DEFF Research Database (Denmark)

    Montalvetti, A; Pena Diaz, Javier; Hurtado, R;

    2000-01-01

    In eukaryotes the enzyme 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase catalyses the synthesis of mevalonic acid, a common precursor to all isoprenoid compounds. Here we report the isolation and overexpression of the gene coding for HMG-CoA reductase from Leishmania major. The protein from...... Leishmania lacks the membrane domain characteristic of eukaryotic cells but exhibits sequence similarity with eukaryotic reductases. Highly purified protein was achieved by ammonium sulphate precipitation followed by chromatography on hydroxyapatite. Kinetic parameters were determined for the protozoan...

  6. NMR evaluation of total statin content and HMG-CoA reductase inhibition in red yeast rice (Monascus spp. food supplements

    Directory of Open Access Journals (Sweden)

    Lachenmeier Dirk W

    2012-03-01

    Full Text Available Abstract Background Red yeast rice (i.e., rice fermented with Monascus spp., as a food supplement, is claimed to be blood cholesterol-lowering. The red yeast rice constituent monacolin K, also known as lovastatin, is an inhibitor of the hydroxymethylglutaryl-CoA (HMG-CoA reductase. This article aims to develop a sensitive nuclear magnetic resonance (NMR method to determine the total statin content of red yeast rice products. Methods The total statin content was determined by a 400 MHz 1H NMR spectroscopic method, based on the integration of the multiplet at δ 5.37-5.32 ppm of a hydrogen at the hexahydronaphthalene moiety in comparison to an external calibration with lovastatin. The activity of HMG-CoA reductase was measured by a commercial spectrophotometric assay kit. Results The NMR detection limit for total statins was 6 mg/L (equivalent to 0.3 mg/capsule, if two capsules are dissolved in 50 mL ethanol. The relative standard deviations were consistently lower than 11%. The total statin concentrations of five red yeast rice supplements were between 1.5 and 25.2 mg per specified daily dose. A dose-dependent inhibition of the HMG-CoA reductase enzyme activity by the red yeast rice products was demonstrated. Conclusion A simple and direct NMR assay was developed to determine the total statin content in red yeast rice. The assay can be applied for the determination of statin content for the regulatory control of red yeast rice products.

  7. Overview of the current attempts toward the medical treatment of cataract

    International Nuclear Information System (INIS)

    A variety of agents are currently available that claim to either prevent, delay, or reverse cataracts associated with aging (senile cataracts), radiation, or diabetes and galactosemia (sugar cataracts). Senile cataract therapy includes formulation containing inorganic salts, nutritional supplements, natural product extracts, sulfhydryl, and sulfonic acid containing compounds and miscellaneous redox and nonsteroidal anti-inflammatory compounds. Agents associated with the treatment of radiation cataracts include antioxidants and free radial scavengers. Aldose reductase inhibitors have been effective in the prevention of sugar cataracts. A summary of these agents and their potential ocular effects are presented

  8. Overview of the current attempts toward the medical treatment of cataract

    Energy Technology Data Exchange (ETDEWEB)

    Kador, P.F.

    1983-04-01

    A variety of agents are currently available that claim to either prevent, delay, or reverse cataracts associated with aging (senile cataracts), radiation, or diabetes and galactosemia (sugar cataracts). Senile cataract therapy includes formulation containing inorganic salts, nutritional supplements, natural product extracts, sulfhydryl, and sulfonic acid containing compounds and miscellaneous redox and nonsteroidal anti-inflammatory compounds. Agents associated with the treatment of radiation cataracts include antioxidants and free radial scavengers. Aldose reductase inhibitors have been effective in the prevention of sugar cataracts. A summary of these agents and their potential ocular effects are presented.

  9. Advances in pharmacological strategies for the prevention of cataract development

    Directory of Open Access Journals (Sweden)

    Gupta S

    2009-01-01

    Full Text Available Cataractous-opacification of the lens is one of the leading causes of blindness in India. The situation can be managed by surgical removal of the cataractous lens. Various pharmacological strategies have been proposed for the prevention and treatment of cataract. Information on possible benefits of putative anticataract agents comes from a variety of approaches, ranging from laboratory experiments, both in vitro and in vivo , to epidemiological studies in patients. This review deals with the various mechanisms, and possible pharmacological interventions for the prevention of cataract. The article also reviews research on potential anticataractous agents, including aldose reductase inhibitors, glutathione boosters, antiglycating agents, vitamins and various drugs from indigenous sources.

  10. Photoaffinity analogues of methotrexate as folate antagonist binding probes. 1. Photoaffinity labeling of murine L1210 dihydrofolate reductase and amino acid sequence of the binding region

    International Nuclear Information System (INIS)

    N/sup α/-(4-Amino-4-deoxy-10-methylpteroyl)-N/sup epsilon/-(4-azido-5-[125I]iodosalicylyl)-L-lysine, a photoaffinity analogue of methotrexate, is only 2-fold less potent than methotrexate in the inhibition of murine L1210 dihydrofolate reductase. Irradiation of the enzyme in the presence of an equimolar concentration of the 125I-labeled analogue ultimately leads to an 8% incorporation of the photoprobe. A 100-fold molar excess of methotrexate essentially blocks this incorporation. Cyanogen bromide digestion of the labeled enzyme, followed by high-pressure liquid chromatography purification of the generated peptides, indicates that greater than 85% of the total radioactivity is incorporated into a single cyanogen bromide peptide. Sequence analysis revealed this peptide to be residues 53-111, with a majority of the radioactivity centered around residues 63-65 (Lys-Asn-Arg). These data demonstrate that the photoaffinity analogue specifically binds to dihydrofolate reductase and covalently modifies the enzyme following irradiation and is therefore a photolabeling agent useful for probing the inhibitor binding domain of the enzyme

  11. Identification of new superwarfarin-type rodenticides by structural similarity. The docking of ligands on the vitamin K epoxide reductase enzyme’s active site

    Directory of Open Access Journals (Sweden)

    Ferencz László

    2015-12-01

    Full Text Available The rodenticide brodifacoum is highly toxic to mammals and birds, and extremely toxic to fish. It is a highly cumulative poison due to its high lipophilicity and extremely slow elimination. For this reason, it may be interesting to find similar compounds in order to enlarge the spectrum of vitamin K epoxide reductase enzyme inhibitors used today in pest control. We used the Similar Compounds search type of the Chemical Structure Search of the PubChem Compound Database to locate records that are similar to the chemical structure of brodifacoum, using pre-specified similarity thresholds. Using the threshold ≥ than 95% for the similar structures criteria, we found 14 compounds (from over 30 million entries that meet this criteria. Two of these compounds have a better binding affinity to vitamin K epoxide reductase enzyme than brodifacoum, but the binding energy of the other 12 substances is also high, having identical or lower lipophilicity; consequently, they will eliminate faster, possibly lacking a part of the adverse effects.

  12. Association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and age of onset in schizophrenia

    DEFF Research Database (Denmark)

    Vares, Maria; Saetre, Peter; Deng, Hong;

    2010-01-01

    Different lines of evidence indicate that methylenetetrahydrofolate reductase (MTHFR) functional gene polymorphisms, causative in aberrant folate-homocysteine metabolism, are associated with increased vulnerability to several heritable developmental disorders. Opposing views are expressed...

  13. Histochemical Localization of Glutathione Dependent NBT—Reductase in Mouse Skin

    Institute of Scientific and Technical Information of China (English)

    YOESHWERSHUKLA

    2001-01-01

    Objective:Localization of the glutathione dependent Nitroblue tetrazolium(NBT) reductase in fresh frozen sections of mouse skin and possible dependence of NBT reductase on tissue thiol levels has been investigated.Methods:The fresh frozen tissue sections(8m thickness)were prepared and incuated in medium containing NBT,reduced glutathione(GSH) and Phosphate uffer,The staining for GSH was performed with mercury orange.Results:The activity of the NBT-reductase in mouse skin has een found to be localized in the areas rich in glutatione and actively proliferating area of the skin.Conclusion:The activity of the NBT-reductase seems to be dependent on the glutatione contents.

  14. Redesigning alcohol dehydrogenases/reductases for more efficient biosynthesis of enantiopure isomers.

    Science.gov (United States)

    Zhang, Rongzhen; Xu, Yan; Xiao, Rong

    2015-12-01

    Alcohol dehydrogenases/reductases predominantly catalyze the asymmetric biosynthesis of optically pure stereoisomers because of their unique chiral constitutions. The enantioselectivities of alcohol dehydrogenases/reductases are substrate- and cofactor-dependent, and therefore they usually catalyze specific reactions with high enantioselectivity under physiological conditions; this may not be suitable for asymmetric biosynthesis with non-natural substrates or non-natural cofactors, and under nonphysiological conditions. It is therefore necessary to modify alcohol dehydrogenases/reductases using various redesigning tools such as directed evolution and rational design, and their combinations, as well as engineering enzyme modules for more efficient production of "non-natural" products. In this article, progress in these aspects of alcohol dehydrogenase/reductase design is reviewed, and future challenges are discussed. PMID:26320091

  15. Small-molecule caspase inhibitors

    International Nuclear Information System (INIS)

    The review considers low-molecular weight inhibitors of caspases, cysteine proteases being key contributors to apoptosis (programmed cell death). The inhibitors with aspartic acid residues or various heterocyclic systems (both synthetic and natural) are covered. Their possible mechanisms of action are discussed. Data on inhibitor structure-activity relationship studies are systematically surveyed. The interactions of the non-peptide fragments of an inhibitor with the enzymes are examined. Examples of the use of some inhibitors for apoptosis suppression are provided.

  16. Small-molecule caspase inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Zhenodarova, S M [Institute for Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow region (Russian Federation)

    2010-02-28

    The review considers low-molecular weight inhibitors of caspases, cysteine proteases being key contributors to apoptosis (programmed cell death). The inhibitors with aspartic acid residues or various heterocyclic systems (both synthetic and natural) are covered. Their possible mechanisms of action are discussed. Data on inhibitor structure-activity relationship studies are systematically surveyed. The interactions of the non-peptide fragments of an inhibitor with the enzymes are examined. Examples of the use of some inhibitors for apoptosis suppression are provided.

  17. Small-molecule caspase inhibitors

    Science.gov (United States)

    Zhenodarova, S. M.

    2010-02-01

    The review considers low-molecular weight inhibitors of caspases, cysteine proteases being key contributors to apoptosis (programmed cell death). The inhibitors with aspartic acid residues or various heterocyclic systems (both synthetic and natural) are covered. Their possible mechanisms of action are discussed. Data on inhibitor structure-activity relationship studies are systematically surveyed. The interactions of the non-peptide fragments of an inhibitor with the enzymes are examined. Examples of the use of some inhibitors for apoptosis suppression are provided.

  18. Comparison of the Stereospecificity and Immunoreactivity of NADH-Ferricyanide Reductases in Plant Membranes

    OpenAIRE

    Fredlund, Kenneth M.; Struglics, André; Widell, Susanne; ASKERLUND, Per; Kader, Jean-Claude; Møller, Ian M.

    1994-01-01

    The substrate stereospecificity of NADH-ferricyanide reductase activities in the inner mitochondrial membrane and peroxisomal membrane of potato (Solanum tuberosum L.) tubers, spinach (Spinacea oleracea L.) leaf plasma membrane, and red beetroot (Beta vulgaris L.) tonoplast were all specific for the [beta]-hydrogen of NADH, whereas the reductases in wheat root (Triticum aestivum L.) endoplasmic reticulum and potato tuber outer mitochondrial membrane were both [alpha]-hydrogen specific. In all...

  19. Nucleotide sequence of a cyanobacterial nifH gene coding for nitrogenase reductase

    OpenAIRE

    Mevarech, Moshe; Rice, Douglas; Haselkorn, Robert

    1980-01-01

    The nucleotide sequence of nifH, the structural gene for nitrogenase reductase (component II or Fe protein of nitrogenase) from the cyanobacterium Anabaena 7120 has been determined. Also reported are 194 bases of the 5′-flanking sequence and 170 bases of the 3′-flanking sequence. The predicted amino acid sequence was compared with that determined for the complete nitrogenase reductase of Clostridium pasteurianum and the cysteine-containing peptides of the protein from Azotobacter vinelandii. ...

  20. Overexpression of Soybean Isoflavone Reductase (GmIFR) Enhances Resistance to Phytophthora sojae in Soybean

    OpenAIRE

    Cheng, Qun; Li, Ninghui; Dong, Lidong; Zhang, Dayong; Fan, Sujie; Jiang, Liangyu; Wang, Xin; Xu, Pengfei; Zhang, Shuzhen

    2015-01-01

    Isoflavone reductase (IFR) is an enzyme involved in the biosynthetic pathway of isoflavonoid phytoalexin in plants. IFRs are unique to the plant kingdom and are considered to have crucial roles in plant response to various biotic and abiotic environmental stresses. Here, we report the characterization of a novel member of the soybean isoflavone reductase gene family GmIFR. Overexpression of GmIFR transgenic soybean exhibited enhanced resistance to Phytophthora sojae. Following stress treatmen...

  1. Protein Method for Investigating Mercuric Reductase Gene Expression in Aquatic Environments

    OpenAIRE

    Ogunseitan, O A

    1998-01-01

    A colorimetric assay for NADPH-dependent, mercuric ion-specific oxidoreductase activity was developed to facilitate the investigation of mercuric reductase gene expression in polluted aquatic ecosystems. Protein molecules extracted directly from unseeded freshwater and samples seeded with Pseudomonas aeruginosa PU21(Rip64) were quantitatively assayed for mercuric reductase activity in microtiter plates by stoichiometric coupling of mercuric ion reduction to a colorimetric redox chain through ...

  2. Soil acidity as affecting micronutrients concentration, nitrato reductase enzyme activity and yield in upland rice plants

    OpenAIRE

    Edemar Moro; Carlos Alexandre Costa Crusciol; Heitor Cantarella; Adriano Stephan Nascente; Adriana Lima Moro; Fernando Broetto

    2013-01-01

    The lowest grain yield of rice under no-tillage system (NTS) in relation to the conventional system may be due to the predominance nitrate in the soil and the low nitrate reductase activity. Another reason may be caused by micronutrient deficiency because of superficially soil acidity corrections. Therefore, the objective of this study was to evaluate the changes caused by soil pH in the N forms in the soil, micronutrients concentration in rice plants, nitrate reductase activity, yield of ric...

  3. Glutathione Reductase/Glutathione Is Responsible for Cytotoxic Elemental Sulfur Tolerance via Polysulfide Shuttle in Fungi*

    OpenAIRE

    Sato, Ikuo; Shimatani, Kanami; Fujita, Kensaku; Abe, Tsuyoshi; Shimizu, Motoyuki; Fujii, Tatsuya; Hoshino, Takayuki; Takaya, Naoki

    2011-01-01

    Fungi that can reduce elemental sulfur to sulfide are widely distributed, but the mechanism and physiological significance of the reaction have been poorly characterized. Here, we purified elemental sulfur-reductase (SR) and cloned its gene from the elemental sulfur-reducing fungus Fusarium oxysporum. We found that NADPH-glutathione reductase (GR) reduces elemental sulfur via glutathione as an intermediate. A loss-of-function mutant of the SR/GR gene generated less sulfide from elemental sulf...

  4. Expression of the mouse dihydrofolate reductase complementary deoxyribonucleic acid in simian virus 40 vectors.

    OpenAIRE

    Subramani, S.; Mulligan, R.; Berg, P

    1981-01-01

    A mouse complementary deoxyribonucleic acid segment coding for the enzyme dihydrofolate reductase has been cloned in two general classes of vectors containing simian virus 40 deoxyribonucleic acid: (i) those that can be propagated as virions in permissive cells and (ii) those that can be introduced into and maintained stably in various mammalian cells. Both types of vectors express the mouse dihydrofolate reductase by using signals supplied by simian virus 40 deoxyribonucleic acid sequences. ...

  5. Interaction of Product Analogs with the Active Site of Rhodobacter sphaeroides Dimethylsulfoxide Reductase

    OpenAIRE

    George, Graham N.; Nelson, Kimberly Johnson; Harris, Hugh H.; Doonan, Christian J.; Rajagopalan, K V

    2007-01-01

    We report a structural characterization using X-ray absorption spectroscopy of Rhodobacter sphaeroides dimethylsulfoxide (DMSO) reductase reduced with trimethylarsine, and show that this is structurally analogous to the physiologically relevant dimethylsulfide-reduced DMSO reductase. Our data unambiguously indicate that these species should be regarded as formal MoIV species, and indicate a classical coordination complex of trimethylarsine oxide, with no special structural distortions. The si...

  6. Purification and properties of a mitochondrial lipoprotein inhibitor of sterol synthesis

    International Nuclear Information System (INIS)

    A lipoprotein inhibitor of hydroxymethylglutaryl CoA reductase (EC 1.1.1.34) and of cholesterol synthesis by rat liver homogenates, was isolated from the mitochondria of starved rats' livers. The isolated lipoprotein complex contained a low molecular weight protein and fatty acids. The fatty acids identified were arachidonic, linoleic, oleic, stearic and palmitic. The saturated fatty acids and oleic acid did not inhibit. Inhibition of the enzyme was to a large extent related to the degree of fatty acid unsaturation. (auth.)

  7. Opposing Effects of Cyclooxygenase-2 (COX-2) on Estrogen Receptor β (ERβ) Response to 5α-Reductase Inhibition in Prostate Epithelial Cells.

    Science.gov (United States)

    Liu, Teresa T; Grubisha, Melanie J; Frahm, Krystle A; Wendell, Stacy G; Liu, Jiayan; Ricke, William A; Auchus, Richard J; DeFranco, Donald B

    2016-07-01

    Current pharmacotherapies for symptomatic benign prostatic hyperplasia (BPH), an androgen receptor-driven, inflammatory disorder affecting elderly men, include 5α-reductase (5AR) inhibitors (i.e. dutasteride and finasteride) to block the conversion of testosterone to the more potent androgen receptor ligand dihydrotestosterone. Because dihydrotestosterone is the precursor for estrogen receptor β (ERβ) ligands, 5AR inhibitors could potentially limit ERβ activation, which maintains prostate tissue homeostasis. We have uncovered signaling pathways in BPH-derived prostate epithelial cells (BPH-1) that are impacted by 5AR inhibition. The induction of apoptosis and repression of the cell adhesion protein E-cadherin by the 5AR inhibitor dutasteride requires both ERβ and TGFβ. Dutasteride also induces cyclooxygenase type 2 (COX-2), which functions in a negative feedback loop in TGFβ and ERβ signaling pathways as evidenced by the potentiation of apoptosis induced by dutasteride or finasteride upon pharmacological inhibition or shRNA-mediated ablation of COX-2. Concurrently, COX-2 positively impacts ERβ action through its effect on the expression of a number of steroidogenic enzymes in the ERβ ligand metabolic pathway. Therefore, effective combination pharmacotherapies, which have included non-steroidal anti-inflammatory drugs, must take into account biochemical pathways affected by 5AR inhibition and opposing effects of COX-2 on the tissue-protective action of ERβ. PMID:27226548

  8. The role of glutathione reductase and related enzymes on cellular redox homoeostasis network.

    Science.gov (United States)

    Couto, Narciso; Wood, Jennifer; Barber, Jill

    2016-06-01

    In this review article we examine the role of glutathione reductase in the regulation, modulation and maintenance of cellular redox homoeostasis. Glutathione reductase is responsible for maintaining the supply of reduced glutathione; one of the most abundant reducing thiols in the majority of cells. In its reduced form, glutathione plays key roles in the cellular control of reactive oxygen species. Reactive oxygen species act as intracellular and extracellular signalling molecules and complex cross talk between levels of reactive oxygen species, levels of oxidised and reduced glutathione and other thiols, and antioxidant enzymes such as glutathione reductase determine the most suitable conditions for redox control within a cell or for activation of programmed cell death. Additionally, we discuss the translation and expression of glutathione reductase in a number of organisms including yeast and humans. In yeast and human cells, a single gene expresses more than one form of glutathione reductase, destined for residence in the cytoplasm or for translocation to different organelles; in plants, however, two genes encoding this protein have been described. In general, insects and kinetoplastids (a group of protozoa, including Plasmodia and Trypanosoma) do not express glutathione reductase or glutathione biosynthetic enzymes. Instead, they express either the thioredoxin system or the trypanothione system. The thioredoxin system is also present in organisms that have the glutathione system and there may be overlapping functions with cross-talk between the two systems. Finally we evaluate therapeutic targets to overcome oxidative stress associated cellular disorders. PMID:26923386

  9. Nitrate reductase activity and its relationship with applied nitrogen in soybean

    International Nuclear Information System (INIS)

    Field experiments were conducted to study the nitrate reductase activity and its relationship to nitrogen by using frame tests (pot without bottom), sand culture and 15N-urea at transplanting in soybean variety Suinong 14. Results showed that the activity of nitrate reductase in leaf changed as a signal peak curve with the soybean growth, lower in vegetative growth phase, higher in reproductive growth period and reached the peak in blooming period, then decreased gradually. Nitrogen application showed obvious effect on the nitrate reductase activity. The activities of nitrate reductase in leaves followed the order of N135 > N90 > N45 > N0 in vegetative growth stage, no clear regularity was found during the whole reproductive growth period. The activities of nitrate reductase in leaves were accorded with the order of upper leaves > mid leaves > lower leaves, and it was very significant differences (P15N labeling method during beginning seed stage and full seed stage shown that 15N abundance in various organs at different node position also followed the same order, suggesting that high level of nitrate reductase activity at upper leaves of soybean promoted the assimilation of NO3-. (authors)

  10. Isobutyraldehyde production from Escherichia coli by removing aldehyde reductase activity

    Directory of Open Access Journals (Sweden)

    Rodriguez Gabriel M

    2012-06-01

    Full Text Available Abstract Background Increasing global demand and reliance on petroleum-derived chemicals will necessitate alternative sources for chemical feedstocks. Currently, 99% of chemical feedstocks are derived from petroleum and natural gas. Renewable methods for producing important chemical feedstocks largely remain unaddressed. Synthetic biology enables the renewable production of various chemicals from microorganisms by constructing unique metabolic pathways. Here, we engineer Escherichia coli for the production of isobutyraldehyde, which can be readily converted to various hydrocarbons currently derived from petroleum such as isobutyric acid, acetal, oxime and imine using existing chemical catalysis. Isobutyraldehyde can be readily stripped from cultures during production, which reduces toxic effects of isobutyraldehyde. Results We adopted the isobutanol pathway previously constructed in E. coli, neglecting the last step in the pathway where isobutyraldehyde is converted to isobutanol. However, this strain still overwhelmingly produced isobutanol (1.5 g/L/OD600 (isobutanol vs 0.14 g/L/OD600 (isobutyraldehyde. Next, we deleted yqhD which encodes a broad-substrate range aldehyde reductase known to be active toward isobutyraldehyde. This strain produced isobutanol and isobutyraldehyde at a near 1:1 ratio, indicating further native isobutyraldehyde reductase (IBR activity in E. coli. To further eliminate isobutanol formation, we set out to identify and remove the remaining IBRs from the E. coli genome. We identified 7 annotated genes coding for IBRs that could be active toward isobutyraldehyde: adhP, eutG, yiaY, yjgB, betA, fucO, eutE. Individual deletions of the genes yielded only marginal improvements. Therefore, we sequentially deleted all seven of the genes and assessed production. The combined deletions greatly increased isobutyraldehyde production (1.5 g/L/OD600 and decreased isobutanol production (0.4 g/L/OD600. By assessing production by

  11. Cholinesterase inhibitors from botanicals

    Directory of Open Access Journals (Sweden)

    Faiyaz Ahmed

    2013-01-01

    Full Text Available Alzheimer′s disease (AD is a progressive neurodegenerative disease, wherein a progressive loss of cholinergic synapses occurs in hippocampus and neocortex. Decreased concentration of the neurotransmitter, acetylcholine (ACh, appears to be critical element in the development of dementia, and the most appropriate therapeutic approach to treat AD and other form of dementia is to restore acetylcholine levels by inhibiting both major form of cholinesterase: Acetylcholinesterase (AChE and butyrylcholinesterase (BChE. Consequently, researches have focused their attention towards finding cholinesterase inhibitors from natural products. A large number of such inhibitors have been isolated from medicinal plants. This review presents a comprehensive account of the advances in field of cholinesterase inhibitor phytoconstituents. The structures of some important phytoconstituents (collected through www.Chemspider.com are also presented and the scope for future research is discussed.

  12. Phosphodiesterase-5 inhibitors.

    Science.gov (United States)

    Cockrill, Barbara A; Waxman, Aaron B

    2013-01-01

    Nitric oxide (NO) signaling plays a key role in modulating vascular tone and remodeling in the pulmonary circulation. The guanylate cyclase/cyclic guanylate monophosphate-signaling pathway primarily mediates nitric oxide signaling. This pathway is critical in normal regulation of the pulmonary vasculature, and is an important target for therapy in patients with pulmonary hypertension. In the pulmonary vasculature, degradation of cGMP is primarily regulated by PDE-5, and inhibition of this enzyme has important effects on pulmonary vasculature smooth muscle tone. Large randomized placebo-controlled trials of PDE-5 inhibitors demonstrated improved exercise capacity, hemodynamics and quality of life in adult patients with PAH. This chapter will discuss the mechanisms of NO signaling in the vasculature, characteristics of the PDE5-inhibitors approved for treatment of PH, and review available data on the use of phosphodiesterase inhibitors in PH. PMID:24092343

  13. Characterization of two alkyl hydroperoxide reductase C homologs alkyl hydroperoxide reductase C_H1 and alkyl hydroperoxide reductase C_H2 in Bacillus subtilis

    Institute of Scientific and Technical Information of China (English)

    Mee-Kyung; Cha; Yoo-Jeen; Bae; Kyu-Jeong; Kim; Byung-Joon; Park; Il-Han; Kim

    2015-01-01

    AIM: To identify alkyl hydroperoxide reductase subunit C(AhpC) homologs in Bacillus subtilis(B. subtilis) and to characterize their structural and biochemical properties. AhpC is responsible for the detoxification of reactive oxygen species in bacteria.METHODS: Two AhpC homologs(AhpC_H1 and AhpC_H2) were identified by searching the B. subtilis database; these were then cloned and expressed in Escherichia coli. AhpC mutants carrying substitutions of catalytically important Cys residues(C37S, C47 S, C166 S, C37/47 S, C37/166 S, C47/166 S, and C37/47/166 S for AhpC_H1; C52 S, C169 S, and C52/169 S for AhpC_H2) were obtained by site-directed mutagenesis and purified, and their structure-function relationship was analyzed. The B. subtilis ahp C genes were disrupted by the short flanking homology method, and the phenotypes of the resulting AhpC-deficient bacteria were examined.RESULTS: Comparative characterization of AhpC homologs indicates that AhpC_H1 contains an extra C37, which forms a disulfide bond with the peroxidatic C47, and behaves like an atypical 2-Cys AhpC, while AhpC_H2 functions like a typical 2-Cys AhpC. Tryptic digestion analysis demonstrated the presence of intramolecular Cys37-Cys47 linkage, which could be reduced by thioredoxin, resulting in the association of the dimer into higher-molecular-mass complexes. Peroxidase activity analysis of Cys→Ser mutants indicated that three Cys residues were involved in the catalysis. AhpC_H1 was resistant to inactivation by peroxide substrates, but had lower activity at physiological H2O2 concentrations compared to AhpC_H2, suggesting that in B. subtilis, the enzymes may be physiologically functional at different substrate concentrations. The exposure to organic peroxides induced AhpC_H1 expression, while AhpC_H1-deficient mutants exhibited growth retardation in the stationary phase, suggesting the role of AhpC_H1 as an antioxidant scavenger of lipid hydroperoxides and a stress-response factor in B. subtilis

  14. Expression analysis of dihydroflavonol 4-reductase genes in Petunia hybrida.

    Science.gov (United States)

    Chu, Y X; Chen, H R; Wu, A Z; Cai, R; Pan, J S

    2015-01-01

    Dihydroflavonol 4-reductase (DFR) genes from Rosa chinensis (Asn type) and Calibrachoa hybrida (Asp type), driven by a CaMV 35S promoter, were integrated into the petunia (Petunia hybrida) cultivar 9702. Exogenous DFR gene expression characteristics were similar to flower-color changes, and effects on anthocyanin concentration were observed in both types of DFR gene transformants. Expression analysis showed that exogenous DFR genes were expressed in all of the tissues, but the expression levels were significantly different. However, both of them exhibited a high expression level in petals that were starting to open. The introgression of DFR genes may significantly change DFR enzyme activity. Anthocyanin ultra-performance liquid chromatography results showed that anthocyanin concentrations changed according to DFR enzyme activity. Therefore, the change in flower color was probably the result of a DFR enzyme change. Pelargonidin 3-O-glucoside was found in two different transgenic petunias, indicating that both CaDFR and RoDFR could catalyze dihydrokaempferol. Our results also suggest that transgenic petunias with DFR gene of Asp type could biosynthesize pelargonidin 3-O-glucoside. PMID:25966276

  15. Methylenetetrahydrofolate Reductase Genotypes, Dietary Habits and Susceptibility to Stomach Cancer

    Institute of Scientific and Technical Information of China (English)

    ChangmingGao; TakezakiToshiro; JianzhongWu; JianhuoDing; YantingLiu; SupingLi; PingSu; XuHu; TianliongXu; HamajimaNobuyuki; TajimaKazuo

    2004-01-01

    OBJECTIVE To study the relation among methylenetetrahydrofolate reductase (MTHFR) C677T genotypes, dietary habits and the risk of stomach cancer (SC).METHODS A case-control study was conducted with 107 cases of SC and 200 population-based controls in Chuzhou district, Huaian, Jiangsu province, China. The epidemiological data were collected, and DNA of peripheral blood leukocytes was obtained from all of the subjects..MTHFR genotypes were detected by PCR-RFLP. RESULTS (1) The prevalence of the MTHFR C/T or T/T genotypes was found to be significantly different between controls (68.5%) and SC cases (79.4%,P=0.0416), the increased risk had an adjusted OR of 1.79 (95%C1:1.01-3.19). (2) Among subjects who had a low intake of garlic or Chinese onion, MTHFR C/T or T/T genotypes significantly increased the risk of developing SC. Among non-tea drinkers or among subjects who had a frequent intakeof meat, the carriers of the MTHFR C/T or T/T genotypes had a higher risk of SC than individuals with the C/C type MTHFR. CONCLUSION The polymorphism of MTHFR C677T was associated with increased risk of developing SC, and that individuals with differing genotypes may have different susceptibilities to SC, based on their exposure level to environmental factors.

  16. Alkyl hydroperoxide reductase: a candidate Helicobacter pylori vaccine.

    Science.gov (United States)

    O'Riordan, Avril A; Morales, Veronica Athie; Mulligan, Linda; Faheem, Nazia; Windle, Henry J; Kelleher, Dermot P

    2012-06-01

    Helicobacter pylori (H. pylori) is the most important etiological agent of chronic active gastritis, peptic ulcer disease and gastric cancer. The aim of this study was to evaluate the efficacy of alkyl hydroperoxide reductase (AhpC) and mannosylated AhpC (mAhpC) as candidate vaccines in the C57BL/6J mouse model of H. pylori infection. Recombinant AhpC was cloned, over-expressed and purified in an unmodified form and was also engineered to incorporate N and C-terminal mannose residues when expressed in the yeast Pichia pastoris. Mice were immunized systemically and mucosally with AhpC and systemically with mAhpC prior to challenge with H. pylori. Serum IgG responses to AhpC were determined and quantitative culture was used to determine the efficacy of vaccination strategies. Systemic prophylactic immunization with AhpC/alum and mAhpC/alum conferred protection against infection in 55% and 77.3% of mice, respectively. Mucosal immunization with AhpC/cholera toxin did not protect against infection and elicited low levels of serum IgG in comparison with systemic immunization. These data support the use of AhpC as a potential vaccine candidate against H. pylori infection. PMID:22512976

  17. Determination of Nitrate Reductase Assay Depending on the Microbial Growth

    International Nuclear Information System (INIS)

    A rapid micro-dilution assay for determination of the antimicrobial susceptibility of different bacterial isolates was developed. This assay is based on the ability of the most of viable organisms to reduce nitrates. The MIC or MBC could be determined by nitrate reductase (NR) only after 30 to 90 min of incubation depending on the behaviour of microbial growth. Bacterial viability is detected by a positive nitrite reduction rather than visible turbidity. The nitrate reduction assay was compared with standard micro-assay using 250 isolates of different taxa against 10 antibiotics belonging to different classes. An excellent agreement of 82.5 % was found between the two methods and only 17.5 % of 1794 trials showed difference in the determined MIC by tow-dilution interval above or below the MIC determined by the turbidimetric method under the same test conditions. However, the nitrate reduction assay was more rapid and sensitive in detecting viable bacteria and so, established an accurate estimate of the minimal inhibitory concentration (MIC) or the minimal bacterial concentration (MBC). The nitrate reduction assay offers the additional advantage that it could be used to determine the MBC without having to subculture the broth. 232 cases of resistance were detected by NR and 4 different media were tested for susceptibility test. The bacterial isolates were exposed to ultra violet (UV) light for different period

  18. Glyoxalase 1 and glutathione reductase 1 regulate anxiety in mice.

    Science.gov (United States)

    Hovatta, Iiris; Tennant, Richard S; Helton, Robert; Marr, Robert A; Singer, Oded; Redwine, Jeffrey M; Ellison, Julie A; Schadt, Eric E; Verma, Inder M; Lockhart, David J; Barlow, Carrolee

    2005-12-01

    Anxiety and fear are normal emotional responses to threatening situations. In human anxiety disorders--such as panic disorder, obsessive-compulsive disorder, post-traumatic stress disorder, social phobia, specific phobias and generalized anxiety disorder--these responses are exaggerated. The molecular mechanisms involved in the regulation of normal and pathological anxiety are mostly unknown. However, the availability of different inbred strains of mice offers an excellent model system in which to study the genetics of certain behavioural phenotypes. Here we report, using a combination of behavioural analysis of six inbred mouse strains with quantitative gene expression profiling of several brain regions, the identification of 17 genes with expression patterns that correlate with anxiety-like behavioural phenotypes. To determine if two of the genes, glyoxalase 1 and glutathione reductase 1, have a causal role in the genesis of anxiety, we performed genetic manipulation using lentivirus-mediated gene transfer. Local overexpression of these genes in the mouse brain resulted in increased anxiety-like behaviour, while local inhibition of glyoxalase 1 expression by RNA interference decreased the anxiety-like behaviour. Both of these genes are involved in oxidative stress metabolism, linking this pathway with anxiety-related behaviour. PMID:16244648

  19. Crystal structures and kinetic properties of enoyl-acyl carrier protein reductase I from Candidatus Liberibacter asiaticus.

    Science.gov (United States)

    Jiang, Ling; Gao, Zengqiang; Li, Yanhua; Wang, Shennan; Dong, Yuhui

    2014-04-01

    Huanglongbing (HLB) is a destructive citrus disease. The leading cause of HLB is Candidatus Liberibacter asiaticus. Fatty acid biosynthesis is essential for bacterial viability and has been validated as a target for the discovery of novel antibacterial agents. Enoyl-acyl carrier protein reductase (also called ENR or FabI and a product of the fabI gene) is an enzyme required in a critical step of bacterial fatty acid biosynthesis and has attracted attention as a target of novel antimicrobial agents. We determined the crystal structures of FabI from Ca. L. asiaticus in its apoform as well as in complex with b-nicotinamide adenine dinucleotide (NAD) at 1.7 and 2.7 Å resolution, respectively, to facilitate the design and screening of small molecule inhibitors of FabI. The monomeric ClFabI is highly similar to other known FabI structures as expected; however, unlike the typical tetramer, ClFabI exists as a hexamer in crystal, whereas as dimer in solution, on the other hand, the substrate binding loop which always disordered in apoform FabI structures is ordered in apo-ClFabI. Interestingly, the structure of ClFabI undergoes remarkable conformational change in the substrate-binding loop in the presence of NAD. We conclude that the signature sequence motif of FabI can be considered as Gly-(Xaa)5-Ser-(Xaa)n-Val-Tyr-(Xaa)6-Lys-(Xaa)n-Thr instead of Tyr-(Xaa)6-Lys. We have further identified isoniazid as a competitive inhibitor with NADH. PMID:24407918

  20. Cross-talk between two antioxidants, thioredoxin reductase and heme oxygenase-1, and therapeutic implications for multiple myeloma.

    Science.gov (United States)

    Raninga, Prahlad V; Di Trapani, Giovanna; Vuckovic, Slavica; Tonissen, Kathryn F

    2016-08-01

    Multiple myeloma (MM) is characterized by an accumulation of abnormal clonal plasma cells in the bone marrow. Despite recent advancements in anti-myeloma therapies, MM remains an incurable disease. Antioxidant molecules are upregulated in many cancers, correlating with tumor proliferation, survival, and chemoresistance and therefore, have been suggested as potential therapeutic targets. This study investigated the cross-talk between two antioxidant molecules, thioredoxin reductase (TrxR) and heme oxygenase-1 (HO-1), and their therapeutic implications in MM. We found that although auranofin, a TrxR inhibitor, significantly inhibited TrxR activity by more than 50% at lower concentrations, myeloma cell proliferation was only inhibited at higher concentrations of auranofin. Inhibition of TrxR using lower auranofin concentrations induced HO-1 protein expression in myeloma cells. Using a sub-lethal concentration of auranofin to inhibit TrxR activity in conjunction with HO-1 inhibition significantly decreased myeloma cell growth and induced apoptosis. TrxR was shown to regulate HO-1 via the Nrf2 signaling pathway in a ROS-dependent manner. Increased HO-1 mRNA levels were observed in bortezomib-resistant myeloma cells compared to parent cells and HO-1 inhibition restored the sensitivity to bortezomib in bortezomib-resistant myeloma cells. These findings indicate that concurrent inhibition of HO-1 with either a TrxR inhibitor or with bortezomib would improve therapeutic outcomes in MM patients. Hence, our findings further support the need to target multiple antioxidant systems alone or in combination with other therapeutics to improve therapeutic outcomes in MM patients. PMID:26795735

  1. Different patterns of 5α-reductase expression, cellular distribution, and testosterone metabolism in human follicular dermal papilla cells

    International Nuclear Information System (INIS)

    Androgens regulate hair growth, and 5α-reductase (5αR) plays a pivotal role in the action of androgens on target organs. To clarify the molecular mechanisms responsible for controlling hair growth, the present study presents evidence that the human follicular dermal papilla cells (DPCs) from either beard (bDPCs) or scalp hair (sDPCs) possess endogenous 5αR activity. Real-time RT-PCR revealed that the highest level of 5αR1 mRNA was found in bDPCs, followed by sDPCs, and a low but detectable level of 5αR1 mRNA was observed in fibroblasts. Minimally detectable levels of 5αR2 mRNA were found in all three cell types. A weak band at 26 kDa corresponding to the human 5αR1 protein was detected by Western blot in both DPCs, but not in fibroblasts. Immuonofluorescence analysis confirmed that 5αR1 was localized to the cytoplasm rather than in the nuclei in both DPCs Furthermore, a 5αR assay using [14C]testosterone labeling in intact cells revealed that testosterone was transformed primarily into androstenedione, and in small amounts, into DHT. Our results demonstrate that the 5αR activities of either bDPCs or sDPCs are stronger than that of dermal fibroblasts, despite the fact that the major steroidogenic activity is attributed to 17β-HSD rather than 5αR among the three cell types. The 5αR1 inhibitor MK386 exhibited a more potent inhibitory effect on 5αR activity than finasteride (5αR2 inhibitor) in bDPCs

  2. Spectrophotometric method for the assay of steroid 5α-reductase activity of rat liver and prostate microsomes.

    Science.gov (United States)

    Iwai, Atsushi; Yoshimura, Teruki; Wada, Keiji; Watabe, Satoshi; Sakamoto, Yuki; Ito, Etsuro; Miura, Toshiaki

    2013-01-01

    A simple spectrophotometric method for the assay of steroid 5α-reductase (5α-SR) was developed in which 5α-dihydrotestosterone (5α-DHT) and 5α-androstane-3α,17β-diol (5α-diol), metabolites formed in the NADPH-dependent reduction of testosterone with enzyme sources of 5α-SR, were measured by enzymatic cycling using 3α-hydroxysteroid dehydrogenase in the presence of excess thionicotinamide-adenine dinucleotide (thio-NAD) and NADH. It was found that 5α-SR activity was proportional to the accumulated thio-NADH having an absorption maximum at 400 nm. Because of the high cycling rate (> 600 cycle per min) and no interference from testosterone, enzymatic cycling can determine the sum of 5α-DHT and 5α-diol at the picomole level without separation from excess testosterone. The present method was readily applicable to the assay of 5α-SR activity of rat liver and prostate microsomes as well as to the assay of inhibitory activity of finasteride, a synthetic inhibitor of 5α-SR. PMID:23574674

  3. Induction of Thioredoxin Reductase 1 by Korean Red Ginseng Water Extract Regulates Cytoprotective Effects on Human Endothelial Cells

    Directory of Open Access Journals (Sweden)

    Hye Rim Park

    2015-01-01

    Full Text Available Korean Red Ginseng is a popular herbal medicine and is widely used in many food products. KRG has biological benefits related to vascular diseases including diabetes, hypertension, atherosclerosis, and other cardiac diseases and KRG has antioxidant and anti-hyperlipidemic actions. KRG decreases the level of oxidative stress and suppresses proinflammatory cytokines and cell adhesion molecules, thus protecting endothelial dysfunction. Mammalian Thioredoxin reductase 1 is an NADPH-dependent selenoprotein, essential for antioxidant defense and DNA synthesis and repair, that regulates the redox system by modulating redox-sensitive transcription factors and thiol-containing proteins. Here, we show that KRG water extract increases the expression of TrxR1 in human umbilical vein endothelial cells via the p38 and PKC-δ signaling pathways. The induction of TrxR1 expression by KRG was confirmed by Western blot analysis and reverse transcription polymerase chain reaction. However, the increase in TrxR1 expression was abolished by specific silencing of the p38 and PKC-δ genes. In addition, we demonstrated that auranofin, a TrxR1 inhibitor, weakens the protective effect of KRG against H2O2-induced cell death as measured by the terminal transferase dUTP nick end labeling assay. These results suggest that KRG may have protective effects in vascular diseases by upregulating TrxR1 in endothelial cells, thereby inhibiting the generation of reactive oxygen species and cell death.

  4. RNA-dependent inhibition of ribonucleotide reductase is a major pathway for 5-azacytidine activity in acute myeloid leukemia

    Science.gov (United States)

    Aimiuwu, Josephine; Wang, Hongyan; Chen, Ping; Xie, Zhiliang; Wang, Jiang; Liu, Shujun; Klisovic, Rebecca; Mims, Alice; Blum, William; Marcucci, Guido

    2012-01-01

    5-Azacytidine (5-azaC) is an azanucleoside approved for myelodysplastic syndrome. Approximately 80%-90% of 5-azaC is believed to be incorporated into RNA, which disrupts nucleic acid and protein metabolism leading to apoptosis. A smaller fraction (10%-20%) of 5-azaC inhibits DNA methylation and synthesis through conversion to decitabine triphosphate and subsequent DNA incorporation. However, its precise mechanism of action remains unclear. Ribonucleotide reductase (RR) is a highly regulated enzyme comprising 2 subunits, RRM1 and RRM2, that provides the deoxyribonucleotides required for DNA synthesis/repair. In the present study, we found for the first time that 5-azaC is a potent inhibitor of RRM2 in leukemia cell lines, in a mouse model, and in BM mononuclear cells from acute myeloid leukemia (AML) patients. 5-azaC–induced RRM2 gene expression inhibition involves its direct RNA incorporation and an attenuated RRM2 mRNA stability. Therefore, 5-azaC causes a major perturbation of deoxyribonucleotide pools. We also demonstrate herein that the initial RR-mediated 5-azaC conversion to decitabine is terminated through its own inhibition. In conclusion, we identify RRM2 as a novel molecular target of 5-azaC in AML. Our findings provide a basis for its more widespread clinical use either alone or in combination. PMID:22517893

  5. Expression of the Aldo-Keto Reductases AKR1B1 and AKR1B10 in Human Cancers.

    Directory of Open Access Journals (Sweden)

    BrianLaffin

    2012-06-01

    Full Text Available The American Cancer Society estimates that there will be more than 1.5 million new cases of cancer in 2011, underscoring the need for identification of new therapeutic targets and development of novel cancer therapies. Previous studies have implicated the human aldo-keto reductases AKR1B1 and AKR1B10 in cancer, and therefore we examined AKR1B1 and AKR1B10 expression across all major human cancer types using the Oncomine cancer gene expression database (Compendia Biosciences, www.oncomine.com. Using this database, we found that expression of of AKR1B1 and AKR1B10 varies greatly by cancer type and tissue of origin, including agreement with previous reports that AKR1B10 is significantly over-expressed in cancers of the lungs and liver. AKR1B1 is more broadly over-expressed in human cancers than AKR1B10, albeit at a generally lower magnitude. AKR1B1 over-expression was found to be associated with shortened patient survival in acute myelogenous leukemias and multiple myelomas. High AKR1B10 expression tends to predict less aggressive clinical course generally, notably within lung cancers, where it tends to be highly over-expressed compared to normal tissue. These findings suggest that AKR1B1 inhibitors in particular hold great potential as novel cancer therapeutics.

  6. 3-oxoacyl-ACP reductase from Schistosoma japonicum: integrated in silico-in vitro strategy for discovering antischistosomal lead compounds.

    Directory of Open Access Journals (Sweden)

    Jian Liu

    Full Text Available BACKGROUND: Schistosomiasis is a disease caused by parasitic worms and more than 200 million people are infected worldwide. The emergence of resistance to the most commonly used drug, praziquantel (PZQ, makes the development of novel drugs an urgent task. 3-oxoacyl-ACP reductase (OAR, a key enzyme involved in the fatty acid synthesis pathway, has been identified as a potential drug target against many pathogenic organisms. However, no research on Schistosoma japonicum OAR (SjOAR has been reported. The characterization of the SjOAR protein will provide new strategies for screening antischistosomal drugs that target SjOAR. METHODOLOGY/PRINCIPAL FINDINGS: After cloning the SjOAR gene, recombinant SjOAR protein was purified and assayed for enzymatic activity. The tertiary structure of SjOAR was obtained by homology modeling and 27 inhibitor candidates were identified from 14,400 compounds through molecular docking based on the structure. All of these compounds were confirmed to be able to bind to the SjOAR protein by BIAcore analysis. Two compounds exhibited strong antischistosomal activity and inhibitory effects on the enzymatic activity of SjOAR. In contrast, these two compounds showed relatively low toxicity towards host cells. CONCLUSIONS/SIGNIFICANCE: The work presented here shows the feasibility of isolation of new antischistosomal compounds using a combination of virtual screening and experimental validation. Based on this strategy, we successfully identified 2 compounds that target SjOAR with strong antischistosomal activity but relatively low cytotoxicity to host cells.

  7. Protein protease inhibitors in insects and comparison with mammalian inhibitors.

    Science.gov (United States)

    Eguchi, M

    1993-01-01

    1. Studies on insect protein protease inhibitors are summarized. Biochemical, genetic and physiological investigations of the silkworm are performed. 2. In addition, the properties and characteristics of fungal protease inhibitors from the silkworm (Bombyx mori) are described and their importance as defensive functions is emphasized. 3. This review also concerns comparative and evolutionary studies of protease inhibitors from various sources. 4. The biological significance of inhibitors is discussed in view of the extensive experimental results. PMID:8365101

  8. Nitrite and Nitrous Oxide Reductase Regulation by Nitrogen Oxides in Rhodobacter sphaeroides f. sp. denitrificans IL106

    OpenAIRE

    Sabaty, Monique; Schwintner, Carole; Cahors, Sandrine; Richaud, Pierre; Verméglio, Andre

    1999-01-01

    We have cloned the nap locus encoding the periplasmic nitrate reductase in Rhodobacter sphaeroides f. sp. denitrificans IL106. A mutant with this enzyme deleted is unable to grow under denitrifying conditions. Biochemical analysis of this mutant shows that in contrast to the wild-type strain, the level of synthesis of the nitrite and N2O reductases is not increased by the addition of nitrate. Growth under denitrifying conditions and induction of N oxide reductase synthesis are both restored b...

  9. Corrosion inhibitor compositions

    International Nuclear Information System (INIS)

    A corrosion inhibitor compositon for hydrocarbon fuels consisting essentially of, by weight, (A) about 75% to 95% of at least one polymerized unsaturated aliphatic monocarboxylic acid, said unsaturated acid having 16 to 18 carbons per molecule, and (B) about 5% to 25% of at least one monoalkenylsuccinic acid in which the alkenyl group as 8 to 18 carbons

  10. Thymidine Phosphorylase Inhibitors

    Czech Academy of Sciences Publication Activity Database

    Nencka, Radim

    Karachi : Bentham Science Publishers, 2011 - (Atta-ur-Rahman, F.; Choudhary, M.), s. 116-147 ISBN 978-1-60805-162-5 R&D Projects: GA MŠk 1M0508; GA AV ČR 1QS400550501 Institutional research plan: CEZ:AV0Z40550506 Keywords : thymidine phosphorylase inhibitors * angiogenesis * cancer chemotherapy Subject RIV: CC - Organic Chemistry

  11. Sunflower trypsin inhibitor-1.

    Science.gov (United States)

    Korsinczky, Michael L J; Schirra, Horst Joachim; Craik, David J

    2004-10-01

    SFTI-1 is a bicyclic 14 amino acid peptide that was originally isolated from the seeds of the sunflower Helianthus annuus. It is a potent inhibitor of trypsin, with a sub-nanomolar K(i) value and is homologous to the active site region of the well-known family of serine protease inhibitors known as the Bowman-Birk trypsin inhibitors. It has a cyclic backbone that is cross-braced by a single disulfide bridge and a network of hydrogen bonds that result in a well-defined structure. SFTI-1 is amenable to chemical synthesis, allowing for the creation of synthetic variants. Alterations to the structure such as linearising the backbone or removing the disulfide bridge do not reduce the potency of SFTI-1 significantly, and minimising the peptide to as few as nine residues results in only a small decrease in reactivity. The creation of linear variants of SFTI-1 also provides a tool for investigating putative linear precursor peptides. The mechanism of biosynthesis of SFTI-1 is not yet known but it seems likely that it is a gene-coded product that has arisen from a precursor protein that may be evolutionarily related to classic Bowman-Birk inhibitors. PMID:15544530

  12. Inhibitors of histone demethylases

    DEFF Research Database (Denmark)

    Lohse, Brian; Kristensen, Jesper L; Kristensen, Line H; Agger, Karl; Helin, Kristian; Gajhede, Michael; Clausen, Rasmus P

    2011-01-01

    Methylated lysines are important epigenetic marks. The enzymes involved in demethylation have recently been discovered and found to be involved in cancer development and progression. Despite the relative recent discovery of these enzymes a number of inhibitors have already appeared. Most of the...

  13. Expression, purification, crystallization and preliminary X-ray analysis of perakine reductase, a new member of the aldo-keto reductase enzyme superfamily from higher plants

    International Nuclear Information System (INIS)

    Perakine reductase, a novel member of the aldo-keto reductase enzyme superfamily of higher plants, is involved in the biosynthesis of monoterpenoid indole alkaloids in the Indian medicinal plant Rauvolfia serpentina. The enzyme has been crystallized in C-centered orthorhombic space group and diffracts to 2.0 Å resolution. Perakine reductase (PR) is a novel member of the aldo-keto reductase enzyme superfamily from higher plants. PR from the plant Rauvolfia serpentina is involved in the biosynthesis of monoterpenoid indole alkaloids by performing NADPH-dependent reduction of perakine, yielding raucaffrinoline. However, PR can also reduce cinnamic aldehyde and some of its derivatives. After heterologous expression of a triple mutant of PR in Escherichia coli, crystals of the purified and methylated enzyme were obtained by the hanging-drop vapour-diffusion technique at 293 K with 100 mM sodium citrate pH 5.6 and 27% PEG 4000 as precipitant. Crystals belong to space group C2221 and diffract to 2.0 Å, with unit-cell parameters a = 58.9, b = 93.0, c = 143.4 Å

  14. Cholesterol, C-Reactive Protein, and Periodontitis: HMG-CoA-Reductase Inhibitors (Statins) as Effect Modifiers

    OpenAIRE

    Thomas Kocher; Peter Meisel; Henri Wallaschofski; Kroemer, Heyo K.; Thomas Kohlmann

    2011-01-01

    Common risk factors of periodontitis and cardiovascular diseases fuel the debate on interrelationships between them. The aim is to prove whether statins may influence periodontal parameters by affecting either of these factors. Out of the 4,290 subjects of SHIP (Study of Health in Pomerania), we included subjects aged >30 years (219 with statins, 2937 without) and excluded edentulous. We determined periodontal measures, cholesterol fractions, and inflammation markers. Statin use and periodont...

  15. Cholesterol, C-Reactive Protein, and Periodontitis: HMG-CoA-Reductase Inhibitors (Statins) as Effect Modifiers.

    Science.gov (United States)

    Meisel, Peter; Kohlmann, Thomas; Wallaschofski, Henri; Kroemer, Heyo K; Kocher, Thomas

    2011-01-01

    Common risk factors of periodontitis and cardiovascular diseases fuel the debate on interrelationships between them. The aim is to prove whether statins may influence periodontal parameters by affecting either of these factors. Out of the 4,290 subjects of SHIP (Study of Health in Pomerania), we included subjects aged >30 years (219 with statins, 2937 without) and excluded edentulous. We determined periodontal measures, cholesterol fractions, and inflammation markers. Statin use and periodontal risk factors were assessed. Gingival plaque and periodontal attachment loss were associated with systemic LDL cholesterol (P dental service, statins were identified as effect modifiers abolishing the relationship between attachment loss and LDL and between gingival plaque and LDL (interactions P < 0.001). No statin-related interaction was detected with increase in CRP. The interaction supports the view of inter-relationships between periodontal and systemic inflammatory mediators. PMID:22203908

  16. Enhanced skin permeation of 5α-reductase inhibitors entrapped into surface-modified liquid crystalline nanoparticles.

    Science.gov (United States)

    Madheswaran, Thiagarajan; Baskaran, Rengarajan; Sundaramoorthy, Pasupathi; Yoo, Bong Kyu

    2015-04-01

    The objective of this study is to enhance skin permeation of finasteride and dutasteride for the treatment of androgenetic alopecia using surface-modified liquid crystalline nanoparticle (sm-LCN) dispersion. LCN entrapped with the drugs was prepared by using monoolein as a liquid crystal former, and surface modification was performed by treatment of the LCN dispersion with same volume of 1 % v/v acetic acid solution containing chitosan. Physicochemical properties of the LCN's were studied with regard to particle size, polydispersity index, zeta potential, and release of the drugs. Skin permeation of drugs entrapped into the LCN and sm-LCN was investigated with porcine abdominal skin using Franz diffusion cell. Cytotoxicity of the LCN's was also studied using human skin keratinocytes. The particle size and zeta potential of the LCN were 197.9 ± 2.5 nm and -20.2 ± 1.9 mV, respectively, and sm-LCN showed slightly bigger size and positive zeta potential due to the presence of thin coating on the surface of the nanoparticles. Compared to LCN, sm-LCN resulted in significantly enhanced skin permeation of the drugs whereas in vitro release was significantly reduced. Cell viability as a measure of cytotoxicity was above 80 % up to 20 μg/ml concentration of both LCN and sm-LCN. In conclusion, sm-LCN may provide a strategy to maximize therapeutic efficacy minimizing unwanted systemic side effects associated with the use of the drugs for the treatment of androgenetic alopecia. PMID:25085659

  17. Mechanisms of the 3- hydroxyl-3-methylglutaryl-coenzyme a reductase inhibitor- induced myotoxicity in human skeletal muscle cell cultures

    OpenAIRE

    Ndountse Tchapda, Léopold

    2005-01-01

    Die Hydroxymethylglutaryl-CoenzymA-(HMG-CoA)-Reduktaseinhibitoren Simvastatin, Lovastatin, Atorvastatin, Pravastatin, Fluvastatin und Pitavastatin wurden im Hinblick auf ihre Wirkungen auf humane Skelettmuskelzellen untersucht. Wir waren in der Lage zu zeigen, dass Statine oxidativen Stress (Dichlorofluoresceindiacetat, Glutathion-Depletierung, Thiobarbitursäure-reaktive Substanzen), Apoptose (mitochondriales Membranpotential DeltaPsim, Caspase-3, Kernmorphologie) und Nekrose (Laktatdehydroge...

  18. Methylenetetrahydrofolate reductase gene polymorphism in Indian stroke patients

    Directory of Open Access Journals (Sweden)

    Kalita J

    2006-01-01

    Full Text Available Background and Aims: In view of the prevailing controversy about the role of Methylenetetrahydrofolate reductase (MTHFR C677T mutation in stroke and paucity of studies from India, this study has been undertaken to evaluate MTHFR C677T gene polymorphism in consecutive ischemic stroke patients and correlate these with folic acid, homocysteine (Hcy and conventional risk factors. Settings and Design: Ischemic stroke patients prospectively evaluated in a tertiary care teaching hospital. Materials and Methods: Computerized tomography proven ischemic stroke patients were prospectively evaluated including clinical, family history of stroke, dietary habits and addictions. Their fasting and postprandial blood sugar, lipid profile, vitamin B12, folic acid and MTHFR gene analysis were done. Statistical Analysis: MTHFR gene polymorphism was correlated with serum folic acid, Vitamin B12 and Hcy levels; family history of stroke in first-degree relatives; and dietary habits; employing Chi-square test. Results: There were 58 patients with ischemic stroke, whose mean age was 50 (4-79 years; among them, 10 were females. MTHFR gene polymorphism was present in 19 (32.8% patients, 3 were homozygous and 16 were heterozygous. Both serum folate and B12 levels were low in 29 (50% patients and Hcy in 48 (83%. Hypertension was present in 28 (48% patients, diabetes in 12 (21%, hyperlipidemia in 52 (90%, smoking in 17 (29%, obesity in 1 (1.7% and family history of stroke in first-degree relatives in 13 (22.4%. There was no significant relationship of MTHFR gene polymorphism with folic acid, B12, Hcy levels, dietary habits and number of risk factors. Vitamin B12 level was low in vegetarians ( P Conclusion: MTHFR gene polymorphism was found in one-third of patients with ischemic stroke and was insignificantly associated with higher frequency of elevated Hcy.

  19. Metabolism of bupropion by carbonyl reductases in liver and intestine.

    Science.gov (United States)

    Connarn, Jamie N; Zhang, Xinyuan; Babiskin, Andrew; Sun, Duxin

    2015-07-01

    Bupropion's metabolism and the formation of hydroxybupropion in the liver by cytochrome P450 2B6 (CYP2B6) has been extensively studied; however, the metabolism and formation of erythro/threohydrobupropion in the liver and intestine by carbonyl reductases (CR) has not been well characterized. The purpose of this investigation was to compare the relative contribution of the two metabolism pathways of bupropion (by CYP2B6 and CR) in the subcellular fractions of liver and intestine and to identify the CRs responsible for erythro/threohydrobupropion formation in the liver and the intestine. The results showed that the liver microsome generated the highest amount of hydroxybupropion (Vmax = 131 pmol/min per milligram, Km = 87 μM). In addition, liver microsome and S9 fractions formed similar levels of threohydrobupropion by CR (Vmax = 98-99 pmol/min per milligram and Km = 186-265 μM). Interestingly, the liver has similar capability to form hydroxybupropion (by CYP2B6) and threohydrobupropion (by CR). In contrast, none of the intestinal fractions generate hydroxybupropion, suggesting that the intestine does not have CYP2B6 available for metabolism of bupropion. However, intestinal S9 fraction formed threohydrobupropion to the extent of 25% of the amount of threohydrobupropion formed by liver S9 fraction. Enzyme inhibition and Western blots identified that 11β-dehydrogenase isozyme 1 in the liver microsome fraction is mainly responsible for the formation of threohydrobupropion, and in the intestine AKR7 may be responsible for the same metabolite formation. These quantitative comparisons of bupropion metabolism by CR in the liver and intestine may provide new insight into its efficacy and side effects with respect to these metabolites. PMID:25904761

  20. Short-chain dehydrogenases/reductases in cyanobacteria.

    Science.gov (United States)

    Kramm, Anneke; Kisiela, Michael; Schulz, Rüdiger; Maser, Edmund

    2012-03-01

    The short-chain dehydrogenases/reductases (SDRs) represent a large superfamily of enzymes, most of which are NAD(H)-dependent or NADP(H)-dependent oxidoreductases. They display a wide substrate spectrum, including steroids, alcohols, sugars, aromatic compounds, and xenobiotics. On the basis of characteristic sequence motifs, the SDRs are subdivided into two main (classical and extended) and three smaller (divergent, intermediate, and complex) families. Despite low residue identities in pairwise comparisons, the three-dimensional structure among the SDRs is conserved and shows a typical Rossmann fold. Here, we used a bioinformatics approach to determine whether and which SDRs are present in cyanobacteria, microorganisms that played an important role in our ecosystem as the first oxygen producers. Cyanobacterial SDRs could indeed be identified, and were clustered according to the SDR classification system. Furthermore, because of the early availability of its genome sequence and the easy application of transformation methods, Synechocystis sp. PCC 6803, one of the most important cyanobacterial strains, was chosen as the model organism for this phylum. Synechocystis sp. SDRs were further analysed with bioinformatics tools, such as hidden Markov models (HMMs). It became evident that several cyanobacterial SDRs show remarkable sequence identities with SDRs in other organisms. These so-called 'homologous' proteins exist in plants, model organisms such as Drosophila melanogaster and Caenorhabditis  elegans, and even in humans. As sequence identities of up to 60% were found between Synechocystis and humans, it was concluded that SDRs seemed to have been well conserved during evolution, even after dramatic terrestrial changes such as the conversion of the early reducing atmosphere to an oxidizing one by cyanobacteria. PMID:22251568

  1. Aldo-keto reductase (AKR) superfamily: genomics and annotation.

    Science.gov (United States)

    Mindnich, Rebekka D; Penning, Trevor M

    2009-07-01

    Aldo-keto reductases (AKRs) are phase I metabolising enzymes that catalyse the reduced nicotinamide adenine dinucleotide (phosphate) (NAD(P)H)-dependent reduction of carbonyl groups to yield primary and secondary alcohols on a wide range of substrates, including aliphatic and aromatic aldehydes and ketones, ketoprostaglandins, ketosteroids and xenobiotics. In so doing they functionalise the carbonyl group for conjugation (phase II enzyme reactions). Although functionally diverse, AKRs form a protein superfamily based on their high sequence identity and common protein fold, the (alpha/beta) 8 -barrel structure. Well over 150 AKR enzymes, from diverse organisms, have been annotated so far and given systematic names according to a nomenclature that is based on multiple protein sequence alignment and degree of identity. Annotation of non-vertebrate AKRs at the National Center for Biotechnology Information or Vertebrate Genome Annotation (vega) database does not often include the systematic nomenclature name, so the most comprehensive overview of all annotated AKRs is found on the AKR website (http://www.med.upenn.edu/akr/). This site also hosts links to more detailed and specialised information (eg on crystal structures, gene expression and single nucleotide polymorphisms [SNPs]). The protein-based AKR nomenclature allows unambiguous identification of a given enzyme but does not reflect the wealth of genomic and transcriptomic variation that exists in the various databases. In this context, identification of putative new AKRs and their distinction from pseudogenes are challenging. This review provides a short summary of the characteristic features of AKR biochemistry and structure that have been reviewed in great detail elsewhere, and focuses mainly on nomenclature and database entries of human AKRs that so far have not been subject to systematic annotation. Recent developments in the annotation of SNP and transcript variance in AKRs are also summarised. PMID:19706366

  2. Aldo-keto reductase (AKR superfamily: Genomics and annotation

    Directory of Open Access Journals (Sweden)

    Mindnich Rebekka D

    2009-07-01

    Full Text Available Abstract Aldo-keto reductases (AKRs are phase I metabolising enzymes that catalyse the reduced nicotinamide adenine dinucleotide (phosphate (NAD(PH-dependent reduction of carbonyl groups to yield primary and secondary alcohols on a wide range of substrates, including aliphatic and aromatic aldehydes and ketones, ketoprostaglan-dins, ketosteroids and xenobiotics. In so doing they functionalise the carbonyl group for conjugation (phase II enzyme reactions. Although functionally diverse, AKRs form a protein superfamily based on their high sequence identity and common protein fold, the (α/(β8-barrel structure. Well over 150 AKR enzymes, from diverse organisms, have been annotated so far and given systematic names according to a nomenclature that is based on multiple protein sequence alignment and degree of identity. Annotation of non-vertebrate AKRs at the National Center for Biotechnology Information or Vertebrate Genome Annotation (vega database does not often include the systematic nomenclature name, so the most comprehensive overview of all annotated AKRs is found on the AKR website (http://www.med.upenn.edu/akr/. This site also hosts links to more detailed and specialised information (eg on crystal structures, gene expression and single nucleotide polymorphisms [SNPs]. The protein-based AKR nomenclature allows unambiguous identification of a given enzyme but does not reflect the wealth of genomic and transcriptomic variation that exists in the various databases. In this context, identification of putative new AKRs and their distinction from pseudogenes are challenging. This review provides a short summary of the characteristic features of AKR biochemistry and structure that have been reviewed in great detail elsewhere, and focuses mainly on nomenclature and database entries of human AKRs that so far have not been subject to systematic annotation. Recent developments in the annotation of SNP and transcript variance in AKRs are also summarised.

  3. Interactions between Barley a-Amylases, Substrates, Inhibitors and Regulatory Proteins

    DEFF Research Database (Denmark)

    Hachem, Maher Abou; Bozonnet, Sophie; Willemoës, Martin;

    2006-01-01

    Barley a-amylase binds sugars at two sites on the enzyme surface in addition to the active site. Crystallography and site-directed mutagenesis highlight the importance of aromatic residues at these surface sites as demonstrated by Kd values determined for ß-cyclodextrin by surface plasmon resonance...... is studied by mutagenesis, crystallography and microcalorimetry. Further improvement of recombinant AMY2 production allows future direct mutational analysis in this isozyme. Specific proteinaceous inhibitors act on a-amylases of different origin. In the complex of barley a-amylase...... are targets of the disulphide reductase thioredoxin h that attacks a specific disulphide bond in BASI and, remarkably, reduces two different disulphide bonds in the barley monomeric and dimeric amylase inhibitors that both belong to the CM-proteins and inhibit animal a-amylase....

  4. Antitubercular drugs for an old target: GSK693 as a promising InhA direct inhibitor.

    Science.gov (United States)

    Martínez-Hoyos, María; Perez-Herran, Esther; Gulten, Gulcin; Encinas, Lourdes; Álvarez-Gómez, Daniel; Alvarez, Emilio; Ferrer-Bazaga, Santiago; García-Pérez, Adolfo; Ortega, Fátima; Angulo-Barturen, Iñigo; Rullas-Trincado, Joaquin; Blanco Ruano, Delia; Torres, Pedro; Castañeda, Pablo; Huss, Sophie; Fernández Menéndez, Raquel; González Del Valle, Silvia; Ballell, Lluis; Barros, David; Modha, Sundip; Dhar, Neeraj; Signorino-Gelo, François; McKinney, John D; García-Bustos, Jose Francisco; Lavandera, Jose Luis; Sacchettini, James C; Jimenez, M Soledad; Martín-Casabona, Nuria; Castro-Pichel, Julia; Mendoza-Losana, Alfonso

    2016-06-01

    Despite being one of the first antitubercular agents identified, isoniazid (INH) is still the most prescribed drug for prophylaxis and tuberculosis (TB) treatment and, together with rifampicin, the pillars of current chemotherapy. A high percentage of isoniazid resistance is linked to mutations in the pro-drug activating enzyme KatG, so the discovery of direct inhibitors (DI) of the enoyl-ACP reductase (InhA) has been pursued by many groups leading to the identification of different enzyme inhibitors, active against Mycobacterium tuberculosis (Mtb), but with poor physicochemical properties to be considered as preclinical candidates. Here, we present a series of InhA DI active against multidrug (MDR) and extensively (XDR) drug-resistant clinical isolates as well as in TB murine models when orally dosed that can be a promising foundation for a future treatment. PMID:27428438

  5. Expression of 5α-Reductase Type 2 Gene in Human Testis, Epididymis and Vas Deferens

    Institute of Scientific and Technical Information of China (English)

    刘德瑜; 吴燕婉; 罗宏志; 张桂元

    2002-01-01

    Objectives To study the expression pattern of 5α-reductase type 2 gene in human malereproductive organsMethods The expression level of 5α-reductase type 2 gene inhuman testis, epididymisand vas deferens tissues was determined by in situ hybridization using Digoxin labeled5α-reductase type 2 cRNA probe.Results The brown granules of hybridizing signals distributed in the cytoplasm ofSertoli and Leydig cells of the testis, the principle cells of epididymis and the epithe-lial cells of vas deferens, but there was no positive signal in the nuclei of above-men-tioned cells. No positive signal was observed in germ cells, basement of the testis,interstium of epididymis and basement, as well as smooth muscle of vas deferens.Conclusion This study confirmed that the 5α-reductase type 2 gene expressed in Ser-toli, Leydig cells of the testis, and the principle cells of epididymis. The expressionpattern of the gene in these cells in human was similar to that of rat and monkey. Thepresence of 5a-reductase type 2 gene in epithelial cells of the vas deferens suggested itmight possess an important physiological role in human reproduction.

  6. Pseudomonas stutzeri N2O reductase contains CuA-type sites

    International Nuclear Information System (INIS)

    N2O reductase (N2O → N2) is the terminal enzyme in the energy-conserving denitrification pathway of soil and marine denitrifying bacteria. The protein is composed of two identical subunits and contains eight copper ions per enzyme molecule. The magnetic circular dichroism spectrum of resting (oxidized) N2O reductase is strikingly similar to the magnetic circular dichroism spectrum of the CuA site in mammalian cytochrome c oxidase and is unlike the magnetic circular dichroism spectra of all other biological copper chromophores obtained to data. Sulfur (or chlorine) scatterers are required to fit the copper extended x-ray absorption fine structure data of both the oxidized and reduced forms of N2O reductase. Satisfactory fits require a Cu-N or Cu-O interaction at 2.0 angstrom, a Cu-(S, Cl) interaction at 2.3 angstrom and an additional Cu-(S, Cl) interaction at ∼ 2.6 angstrom (oxidized) or ∼ 2.7 angstrom (reduced). Comparison of the N2O reductase sequence, determined by translating the structural NosZ gene, with cytochrome c oxidase subunit II sequences from several sources indicates that a Gly-Xaa-Xaa-Xaa-Xaa-Xaa-Cys-Ser-Xaa-Xaa-Cys-Xaa-Xaa-Xaa-Xaa-Xaa-His stretch if high conserved. This sequence contains three of the probable ligands in a CuA-type site Collectively these data establish that Pseudomonas stutzeri N2O reductase contains CuA-type sites

  7. Structural and biochemical properties of cloned and expressed human and rat steroid 5α-reductases

    International Nuclear Information System (INIS)

    The microsomal enzyme steroid 5α-reductase is responsible for the conversion of testosterone into the more potent androgen dihydrotestosterone. In man, this steroid acts on a variety of androgen-responsive target tissues to mediate such diverse endocrine processes as male sexual differentiation in the fetus and prostatic growth in men. Here we describe the isolation, structure, and expression of a cDNA encoding the human steroid 5α-reductase. A rat cDNA was used as a hybridization probe to screen a human prostate cDNA library. A 2.1-kilobase cDNA was identified and DNA sequence analysis indicated that the human steroid 5α-reductase was a hydrophobic protein of 259 amino acids with a predicted molecular weight of 29,462. A comparison of the human and rat protein sequences revealed a 60% identity. Transfection of expression vectors containing the human and rat cDNAs into simian COS cells resulted in the synthesis of high levels of steroid 5α-reductase enzyme activity. Both enzymes expressed in COS cells showed similar substrate specificities for naturally occurring steroid hormones. However, synthetic 4-azasteroids demonstrated marked differences in their abilities to inhibit the human and rat steroid 5α-reductases

  8. Crystal Structures of Wild-type and Mutant Methicillin-resistant Staphylococcus aureus Dihydrofolate Reductase Reveal an Alternative Conformation of NADPH that may be Linked to Trimethoprim Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Frey, K.; Liu, J; Lombardo, M; Bolstad, D; Wright, D; Anderson, A

    2009-01-01

    Both hospital- and community-acquired Staphylococcus aureus infections have become major health concerns in terms of morbidity, suffering and cost. Trimethoprim-sulfamethoxazole (TMP-SMZ) is an alternative treatment for methicillin-resistant S. aureus (MRSA) infections. However, TMP-resistant strains have arisen with point mutations in dihydrofolate reductase (DHFR), the target for TMP. A single point mutation, F98Y, has been shown biochemically to confer the majority of this resistance to TMP. Using a structure-based approach, we have designed a series of novel propargyl-linked DHFR inhibitors that are active against several trimethoprim-resistant enzymes. We screened this series against wild-type and mutant (F98Y) S. aureus DHFR and found that several are active against both enzymes and specifically that the meta-biphenyl class of these inhibitors is the most potent. In order to understand the structural basis of this potency, we determined eight high-resolution crystal structures: four each of the wild-type and mutant DHFR enzymes bound to various propargyl-linked DHFR inhibitors. In addition to explaining the structure-activity relationships, several of the structures reveal a novel conformation for the cofactor, NADPH. In this new conformation that is predominantly associated with the mutant enzyme, the nicotinamide ring is displaced from its conserved location and three water molecules complete a network of hydrogen bonds between the nicotinamide ring and the protein. In this new position, NADPH has reduced interactions with the inhibitor. An equilibrium between the two conformations of NADPH, implied by their occupancies in the eight crystal structures, is influenced both by the ligand and the F98Y mutation. The mutation induced equilibrium between two NADPH-binding conformations may contribute to decrease TMP binding and thus may be responsible for TMP resistance.

  9. [JAK2 inhibitors].

    Science.gov (United States)

    Hernández Boluda, Juan Carlos; Gómez, Montse; Pérez, Ariadna

    2016-07-15

    Pharmacological inhibition of the kinase activity of JAK proteins can interfere with the signaling of immunomodulatory cytokines and block the constitutive activation of the JAK-STAT pathway that characterizes certain malignancies, including chronic myeloproliferative neoplasms. JAK inhibitors may, therefore, be useful to treat malignancies as well as inflammatory or immune disorders. Currently, the most significant advances have been made in the treatment of myelofibrosis, where these drugs may lead to a remarkable improvement in the control of hyperproliferative manifestations. However, available data suggest that this treatment is not curative of myelofibrosis. In general, JAK2 inhibition induces cytopaenias, with this being considered a class side-effect. By contrast, the extrahaematologic toxicity profile varies significantly among the different JAK inhibitors. At present, there are several clinical trials evaluating the combination of ruxolitinib with other drugs, in order to improve its therapeutic activity as well as reducing haematologic toxicity. PMID:27033437

  10. Benzoylurea Chitin Synthesis Inhibitors.

    Science.gov (United States)

    Sun, Ranfeng; Liu, Chunjuan; Zhang, Hao; Wang, Qingmin

    2015-08-12

    Benzoylurea chitin synthesis inhibitors are widely used in integrated pest management (IPM) and insecticide resistance management (IRM) programs due to their low toxicity to mammals and predatory insects. In the past decades, a large number of benzoylurea derivatives have been synthesized, and 15 benzoylurea chitin synthesis inhibitors have been commercialized. This review focuses on the history of commercial benzolyphenylureas (BPUs), synthetic methods, structure-activity relationships (SAR), action mechanism research, environmental behaviors, and ecotoxicology. Furthermore, their disadvantages of high risk to aquatic invertebrates and crustaceans are pointed out. Finally, we propose that the para-substituents at anilide of benzoylphenylureas should be the functional groups, and bipartite model BPU analogues are discussed in an attempt to provide new insight for future development of BPUs. PMID:26168369

  11. Alpha glucosidase inhibitors.

    Science.gov (United States)

    Kalra, Sanjay

    2014-04-01

    Alpha glucosidase inhibitors (AGIs) are a unique class of anti-diabetic drugs. Derived from bacteria, these oral drugs are enzyme inhibitors which do not have a pancreato -centred mechanism of action. Working to delay carbohydrate absorption in the gastrointestinal tract, they control postprandial hyperglycaemia and provide unquestioned cardiovascular benefit. Specially suited for a traditional Pakistani carbohydrate-rich diet, AGIs have been termed the 'untapped diamonds' of diabetology. The use of these oral antidiabetic drugs (OADs) that target pathophysiology in the early stages of type 2 diabetes, notably to reduce postprandial hyperglycaemia and hyperinsulinaemia will inevitably increase with time. This review describes the history of their development, mechanism of action, basic and clinical pharmacology, and suggests practical, evidence-based guidance for their optimal use. PMID:24864650

  12. Triclosan Derivatives: Towards Potent Inhibitors of Drug-Sensitive and Drug-Resistant Mycobacterium tuberculosis

    Energy Technology Data Exchange (ETDEWEB)

    Freundlich, Joel S.; Wang, Feng; Vilchèze, Catherine; Gulten, Gulcin; Langley, Robert; Schiehser, Guy A.; Jacobus, David P.; Jacobs, Jr., William R.; Sacchettini, James C.; (Einstein); (TAM); (Jacobus)

    2009-06-30

    Isoniazid (INH) is a frontline antitubercular drug that inhibits the enoyl acyl carrier protein reductase InhA. Novel inhibitors of InhA that are not cross-resistant to INH represent a significant goal in antitubercular chemotherapy. The design, synthesis, and biological activity of a series of triclosan-based inhibitors is reported, including their promising efficacy against INH-resistant strains of M. tuberculosis. Triclosan has been previously shown to inhibit InhA, an essential enoyl acyl carrier protein reductase involved in mycolic acid biosynthesis, the inhibition of which leads to the lysis of Mycobacterium tuberculosis. Using a structure-based drug design approach, a series of 5-substituted triclosan derivatives was developed. Two groups of derivatives with alkyl and aryl substituents, respectively, were identified with dramatically enhanced potency against purified InhA. The most efficacious inhibitor displayed an IC{sub 50} value of 21 nM, which was 50-fold more potent than triclosan. X-ray crystal structures of InhA in complex with four triclosan derivatives revealed the structural basis for the inhibitory activity. Six selected triclosan derivatives were tested against isoniazid-sensitive and resistant strains of M. tuberculosis. Among those, the best inhibitor had an MIC value of 4.7 {mu}g mL{sup -1} (13 {mu}M), which represents a tenfold improvement over the bacteriocidal activity of triclosan. A subset of these triclosan analogues was more potent than isoniazid against two isoniazid-resistant M. tuberculosis strains, demonstrating the significant potential for structure-based design in the development of next generation antitubercular drugs.

  13. Update on Aromatase Inhibitors

    Directory of Open Access Journals (Sweden)

    Seifert-Klauss V

    2015-01-01

    Full Text Available Aromatase inhibitors (AI block the last phase of estrogen production in many types of tissues which express the enzym aromatase, among them muscle, liver, adrenal, brain and fat. The enzyme catalyzes the last step of the biosynthesis of the estrogens, i. e. the aromatisation of testosterone to estradiol and of androstendion to estrone. Aromatase is localized in the membrane of the endoplasmatic reticulum and is also produced in the placenta and the gonads. Mutations in the gene CYP19A1, which codes for aromatase, can lead either to lack or excess of aromatase. Gene polymorphisms also influence the amount of bioavailable estrogen and bone density.br Indications: AI are approved for the treatment of postmenopausal women with hormone receptor positive breast cancer, both in the adjuvant setting as well as after recurrence and in progressive disease. In premenopausal and in perimenopausal women AI cause an increased sensitivity of the ovaries to follicle stimulating hormone (FSH and can thereby lead to a boosted estrogen answer – this effect is particularly pronounced in early perimenopausal women – so that these situations demand a combination with GnRH-analogue if AI treatment is to be initiated. Alternatively, tamoxifene may be used in premenopausal patients, with or without GnRH analogues. Treatment of premenopausal patients with hormone receptor positive breast cancer with aromatase inhibiting therapy alone constitutes an absolute contraindication. Aromatase inhibitors do not lead to estrogen receptor downregulation or block the receptor such as tamoxifene. An exceptional application is the application in reproductive medicine in women who do not have hormone receptor positive breast cancer: because of the higher sensitivity induced by AI-co-therapy, FSH-doses and -costs for assisted reproduction are reduced, and ovarian hyperstimulation syndrome (OHSS may be avoided. For premenopausal diseases which are said to be positively affected by

  14. Biochemical predetermination of the NO synthase and nitrite reductase components of the nitric oxide cycle.

    Science.gov (United States)

    Reutov, V P

    1999-05-01

    This review presents some aspects of a concept of cellular evolution bearing a relationship to nitrate--nitrite respiration, the endosymbiosis theory, and the origin of NO synthase and nitrite reductase activity in heme-containing proteins. Analysis of structural and functional unity of the NO synthase and nitrite reductase systems suggests that these systems did not arise without any relation to evolutionarily ancient energetic systems of cells. The use of symmetry principles reveals commonalities among many electron transport chains which in the language of physics is called "invariance". This work also comparatively analyzes the nitric oxide cycle and the known nitrogen cycle. The ideas about evolution of the NO synthase and nitrite reductase systems developed here are clearly compatible with the endosymbiotic theory and the hypothesis that nitrate--nitrite respiration was a precursor of oxygen-dependent respiration. PMID:10381613

  15. Crystallization and preliminary X-ray crystallographic studies of pig heart carbonyl reductase

    International Nuclear Information System (INIS)

    Pig heart carbonyl reductase has been crystallized in the presence of NADPH. Diffraction data have been collected using synchrotron radiation. Pig heart carbonyl reductase (PHCR), which belongs to the short-chain dehydrogenase/reductase (SDR) family, has been crystallized by the hanging-drop vapour-diffusion method. Two crystal forms (I and II) have been obtained in the presence of NADPH. Form I crystals belong to the tetragonal space group P42, with unit-cell parameters a = b = 109.61, c = 94.31 Å, and diffract to 1.5 Å resolution. Form II crystals belong to the tetragonal space group P41212, with unit-cell parameters a = b = 120.10, c = 147.00 Å, and diffract to 2.2 Å resolution. Both crystal forms are suitable for X-ray structure analysis at high resolution

  16. Putative Role of the Aldo-Keto Reductase from Trypanosoma cruzi in Benznidazole Metabolism.

    Science.gov (United States)

    Garavaglia, Patricia Andrea; Laverrière, Marc; Cannata, Joaquín J B; García, Gabriela Andrea

    2016-05-01

    Benznidazole (Bz), the drug used for treatment of Chagas' disease (caused by the protozoan Trypanosoma cruzi), is activated by a parasitic NADH-dependent type I nitroreductase (NTR I). However, several studies have shown that other enzymes are involved. The aim of this study was to evaluate whether the aldo-keto reductase from T. cruzi (TcAKR), a NADPH-dependent oxido-reductase previously described by our group, uses Bz as the substrate. We demonstrated that both recombinant and native TcAKR enzymes reduce Bz by using NADPH, but not NADH, as a cofactor. TcAKR-overexpressing epimastigotes showed higher NADPH-dependent Bz reductase activity and a 50% inhibitory concentration (IC50) value for Bz 1.8-fold higher than that of the controls, suggesting that TcAKR is involved in Bz detoxification instead of activation. To understand the role of TcAKR in Bz metabolism, we studied TcAKR expression and NADPH/NADH-dependent Bz reductase activities in two T. cruzi strains with differential susceptibility to Bz: CL Brener and Nicaragua. Taking into account the results obtained with TcAKR-overexpressing epimastigotes, we expected the more resistant strain, Nicaragua, to have higher TcAKR levels than CL Brener. However, the results were the opposite. CL Brener showed 2-fold higher TcAKR expression and 5.7-fold higher NADPH-Bz reduction than the Nicaragua strain. In addition, NADH-dependent Bz reductase activity, characteristic of NTR I, was also higher in CL Brener than in Nicaragua. We conclude that although TcAKR uses Bz as the substrate, TcAKR activity is not a determinant of Bz resistance in wild-type strains and may be overcome by other enzymes involved in Bz activation, such as NADPH- and NADH-dependent reductases. PMID:26856844

  17. Characterisation of a desmosterol reductase involved in phytosterol dealkylation in the silkworm, Bombyx mori.

    Directory of Open Access Journals (Sweden)

    Leonora F Ciufo

    Full Text Available Most species of invertebrate animals cannot synthesise sterols de novo and many that feed on plants dealkylate phytosterols (mostly C(29 and C(28 yielding cholesterol (C(27. The final step of this dealkylation pathway involves desmosterol reductase (DHCR24-catalysed reduction of desmosterol to cholesterol. We now report the molecular characterisation in the silkworm, Bombyx mori, of such a desmosterol reductase involved in production of cholesterol from phytosterol, rather than in de novo synthesis of cholesterol. Phylogenomic analysis of putative desmosterol reductases revealed the occurrence of various clades that allowed for the identification of a strong reductase candidate gene in Bombyx mori (BGIBMGA 005735. Following PCR-based cloning of the cDNA (1.6 kb and its heterologous expression in Saccharomyces cerevisae, the recombinant protein catalysed reduction of desmosterol to cholesterol in an NADH- and FAD-dependent reaction.Conceptual translation of the cDNA, that encodes a 58.9 kDa protein, and database searching, revealed that the enzyme belongs to an FAD-dependent oxidoreductase family. Western blotting revealed reductase protein expression exclusively in the microsomal subcellular fraction and primarily in the gut. The protein is peripherally associated with microsomal membranes. 2D-native gel and PAGE analysis revealed that the reductase is part of a large complex with molecular weight approximately 250 kDa. The protein occurs in midgut microsomes at a fairly constant level throughout development in the last two instars, but is drastically reduced during the wandering stage in preparation for metamorphosis. Putative Broad Complex transcription factor-binding sites detectable upstream of the DHCR24 gene may play a role in this down-regulation.

  18. GENERATION OF THE GLYCYL RADICAL OF THE ANAEROBIC ESCHERICHIA-COLI RIBONUCLEOTIDE REDUCTASE REQUIRES A SPECIFIC ACTIVATING ENZYME

    NARCIS (Netherlands)

    SUN, XY; ELIASSON, R; PONTIS, E; ANDERSSON, J; BUIST, G; SJOBERG, BM; REICHARD, P

    1995-01-01

    The anaerobic ribonucleotide reductase from Escherichia coli contains a glycyl radical as part of its polypeptide structure. The radical is generated by an enzyme system present in E. coli. The reductase is coded for by the nrdD gene located at 96 min. Immediately downstream, we now find an open rea

  19. Direct enzyme assay evidence confirms aldehyde reductase function of Ydr541cp and Ygl039wp from Saccharomyces cerevisiae

    Science.gov (United States)

    Aldehyde reductase gene ARI1 is a recently characterized member of intermediate subfamily under SDR (short-chain dehydrogenase/reductase) superfamily that revealed mechanisms of in situ detoxification of furfural and HMF for tolerance of Saccharomyces cerevisiae. Uncharacterized open reading frames ...

  20. Feedback regulation of cholesterol synthesis:sterol-accelerated ubiquitination and degradation of HMG CoA reductase

    Institute of Scientific and Technical Information of China (English)

    Russell A DeBose-Boyd

    2008-01-01

    3Hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase produces mevalonate,an important intermediate in the synthesis of cholesterol and essential nonsterol isoprenoids.The reductase is subject to an exorbitant amount of feedback control through multiple mechanisms that are mediated by sterol and nonsterol end-products of mevalonate metabolism.Here,Ⅰwill discuss recent advances that shed light on one mechanism for control of reductase,which involves rapid degradation of the enzyme.Accumulation of certain sterols triggers binding of reductase to endoplasmic reticulum (ER) membrane proteins called Insig-1 and Insig-2.Reductase-Insig binding results in recruitment of a membrane-associated ubiquitin ligase called gp78,which initiates ubiquitination of reductase.This ubiquitination is an obligatory reaction for recognition and degradation of reductase from ER membranes by cytosolic 26S proteasomes.Thus,sterol-accelerated degradation of reductase represents an example of how a general cellular process (ER-associated degradation) is used to control an important metabolic pathway (cholesterol synthesis).

  1. Multiple Types of 8-Vinyl Reductases for (Bacterio)Chlorophyll Biosynthesis Occur in Many Green Sulfur Bacteria ▿

    OpenAIRE

    Liu, Zhenfeng; Bryant, Donald A.

    2011-01-01

    Two 8-vinyl reductases, BciA and BciB, have been identified in chlorophototrophs. The bciA gene of Chlorobaculum tepidum was replaced with genes similar to bciB from other green sulfur bacteria. Pigment analyses of the complemented strains showed that the bciB homologs encode 8-vinyl reductases similar to those of cyanobacteria.

  2. Studies on some characteristics of nitrate reductase from sugar beet (Beta vulgaris L.)leaves

    Institute of Scientific and Technical Information of China (English)

    LiWenhua; YanGuiping; 等

    1994-01-01

    Some characteristics of nitrate reductase from sugar beet leaves shown in this paper were as follows:The nitrate reductase from sugar beet leaves required NADH as an electron donor.Accordingly,the nitrate reductase was classified as NADH-dependent(E.C.1.6.61).The Km value of the nitrate reductase for NADH and NO3- were 0.86m mol and 0.18μ mol respectively.The optimum pH in reaction mixture solution for nitrate reduction activity was 7.5.The effect of variable concentrations of inorganic phosphorus in the reaction buffer on nitrate reductase activity was investigated.When the inorganic phosphorus concentration was below 35m mol,the nitrate reductase activity was increased with increase of inorganic phosphorus concentration.Conversely,when the inorganic phosphorus concentration was over 35m mol,the nitrate reductase activity was inhibited.The nitrate reductase activity assayed in vitro was 3.2 and 5.6times of that assayed in vivo under the condition of exogenous and endogenous ground substance respectively.

  3. The role of 5'-adenylylsulfate reductase in the sulfur assimilation pathway of soybean: molecular cloning, kinetic characterization, and gene expression

    Science.gov (United States)

    Soybean seeds are a major source of protein, but contain low levels of sulfur-containing amino acids. With the objective of studying the sulfur assimilation pathway of soybean, a full-length cDNA clone for 5’-adenylylsulfate reductase (APS reductase) was isolated and characterized. The cDNA clone ...

  4. Inverse relationship between age-dependent erythrocyte activity of methaemoglobin reductase and prilocaine-induced methaemoglobinaemia during infancy

    DEFF Research Database (Denmark)

    Nilsson, A; Engberg, G; Henneberg, S; Danielson, K; De Verdier, C H

    1990-01-01

    concentrations of local anaesthetics were low (maximum values: prilocaine 78 ng ml-1, lignocaine 412 ng ml-1). The activity of erythrocyte MetHb reductase (cytochrome b5 reductase) was analysed. Data from a previously studied group of infants aged 3-12 months were included also. Enzyme activity did not reach...

  5. Identification of the bchP gene, encoding geranylgeranyl reductase in Chlorobaculum tepidum

    DEFF Research Database (Denmark)

    Gomez Maqueo Chew, Aline; Frigaard, Niels-Ulrik; Bryant, Donald A

    2008-01-01

    The Chlorobaculum tepidum genome contains two paralogous genes, CT2256 and CT1232, whose products are members of the FixC dehydrogenase superfamily and have sequence similarity to geranylgeranyl reductases. Each gene was insertionally inactivated, and the resulting mutants were characterized. CT2......2256 encodes geranylgeranyl reductase (BchP); CT1232 is not involved in bacteriochlorophyll or chlorophyll biosynthesis....

  6. Synthesis and degradation of nitrate reductase during the cell cycle of Chlorella sorokiniana

    Science.gov (United States)

    Velasco, P. J.; Tischner, R.; Huffaker, R. C.; Whitaker, J. R.

    1989-01-01

    Studies on the diurnal variations of nitrate reductase (NR) activity during the life cycle of synchronized Chlorella sorokiniana cells grown with a 7:5 light-dark cycle showed that the NADH:NR activity, as well as the NR partial activities NADH:cytochrome c reductase and reduced methyl viologen:NR, closely paralleled the appearance and disappearance of NR protein as shown by sodium dodecyl sulfate gel electrophoresis and immunoblots. Results of pulse-labeling experiments with [35S]methionine further confirmed that diurnal variations of the enzyme activities can be entirely accounted for by the concomitant synthesis and degradation of the NR protein.

  7. Glyphosate inhibition of ferric reductase activity in iron deficient sunflower roots

    OpenAIRE

    Öztürk, Levent; Ozturk, Levent; Yazıcı, Mustafa Atilla; Yazici, Mustafa Atilla; Eker, Selim; Gökmen, Özay Özgür; Gokmen, Ozay Ozgur; Römheld, Volker; Romheld, Volker; ÇAKMAK, İsmail; Cakmak, Ismail

    2007-01-01

    Iron (Fe) deficiency is increasingly being observed in cropping systems with frequent glyphosate applications. A likely reason for this is that glyphosate interferes with root uptake of Fe by inhibiting ferric reductase in roots required for Fe acquisition by dicot and nongrass species. This study investigated the role of drift rates of glyphosate (0.32, 0.95 or 1.89 mM glyphosate corresponding to 1, 3 and 6% of the recommended herbicidal dose, respectively) on ferric reductase activity of...

  8. Mutational analysis of the nor gene cluster which encodes nitric-oxide reductase from Paracoccus denitrificans.

    Science.gov (United States)

    de Boer, A P; van der Oost, J; Reijnders, W N; Westerhoff, H V; Stouthamer, A H; van Spanning, R J

    1996-12-15

    The genes that encode the hc-type nitric-oxide reductase from Paracoccus denitrificans have been identified. They are part of a cluster of six genes (norCBQDEF) and are found near the gene cluster that encodes the cd1-type nitrite reductase, which was identified earlier [de Boer, A. P. N., Reijnders, W. N. M., Kuenen, J. G., Stouthamer, A. H. & van Spanning, R. J. M. (1994) Isolation, sequencing and mutational analysis of a gene cluster involved in nitrite reduction in Paracoccus denitrificans, Antonie Leeu wenhoek 66, 111-127]. norC and norB encode the cytochrome-c-containing subunit II and cytochrome b-containing subunit I of nitric-oxide reductase (NO reductase), respectively. norQ encodes a protein with an ATP-binding motif and has high similarity to NirQ from Pseudomonas stutzeri and Pseudomonas aeruginosa and CbbQ from Pseudomonas hydrogenothermophila. norE encodes a protein with five putative transmembrane alpha-helices and has similarity to CoxIII, the third subunit of the aa3-type cytochrome-c oxidases. norF encodes a small protein with two putative transmembrane alpha-helices. Mutagenesis of norC, norB, norQ and norD resulted in cells unable to grow anaerobically. Nitrite reductase and NO reductase (with succinate or ascorbate as substrates) and nitrous oxide reductase (with succinate as substrate) activities were not detected in these mutant strains. Nitrite extrusion was detected in the medium, indicating that nitrate reductase was active. The norQ and norD mutant strains retained about 16% and 23% of the wild-type level of NorC, respectively. The norE and norF mutant strains had specific growth rates and NorC contents similar to those of the wild-type strain, but had reduced NOR and NIR activities, indicating that their gene products are involved in regulation of enzyme activity. Mutant strains containing the norCBQDEF region on the broad-host-range vector pEG400 were able to grow anaerobically, although at a lower specific growth rate and with lower

  9. Properties of a Thermostable Nitrate Reductase from the Hyperthermophilic Archaeon Pyrobaculum aerophilum

    OpenAIRE

    Afshar, Sepideh; Johnson, Eric; de Vries, Simon; Schröder, Imke

    2001-01-01

    The nitrate reductase of the hyperthermophilic archaeon Pyrobaculum aerophilum was purified 137-fold from the cytoplasmic membrane. Based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, the enzyme complex consists of three subunits with apparent molecular weights of 130,000, 52,000, and 32,000. The enzyme contained molybdenum (0.8-mol/mol complex), iron (15.4-mol/mol complex) and cytochrome b (0.49-mol/mol complex) as cofactors. The P. aerophilum nitrate reductase disti...

  10. Imaging the activity of nitrate reductase by means of a scanning electrochemical microscope.

    Science.gov (United States)

    Zaumseil, J; Wittstock, G; Bahrs, S; Steinrücke, P

    2000-06-01

    Scanning electrochemical microscopy (SECM) was used to characterize immobilized nitrate reductase (NaR) from Pseudonomonas stutzeri (E.C. 1.7.99.4). Nitrate reductase with membrane fragment was embedded in a polyurethane hydrogel in a capillary and solubilized NaR without membrane fragment was covalently coupled to a diaminoethyl-cellulose-carbamitate film on glass. After systematic studies of possible mediators, SECM feedback imaging of both forms of immobilized NaR was accomplished with methylviologen as redox mediator. PMID:11225859

  11. Crystallization and preliminary X-ray diffraction studies of ferredoxin reductase from Leptospira interrogans

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Alessandro S.; Ferrarezi, Thiago [Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador Saocarlense 400, São Carlos, SP, 13560-970 (Brazil); Catalano-Dupuy, Daniela L.; Ceccarelli, Eduardo A. [Facultad de Ciencias Bioquímicas y Farmacéuticas, Molecular Biology Division, Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario (Argentina); Polikarpov, Igor, E-mail: ipolikarpov@if.sc.usp.br [Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador Saocarlense 400, São Carlos, SP, 13560-970 (Brazil)

    2006-07-01

    Crystals adequate for X-ray diffraction analysis have been prepared from L. interrogans ferredoxin-NADP{sup +} reductase. Ferredoxin-NADP{sup +} reductase (FNR) is an FAD-containing enzyme that catalyzes electron transfer between NADP(H) and ferredoxin. Here, results are reported of the recombinant expression, purification and crystallization of FNR from Leptospira interrogans, a parasitic bacterium of animals and humans. The L. interrogans FNR crystals belong to a primitive monoclinic space group and diffract to 2.4 Å resolution at a synchrotron source.

  12. Crystallization and preliminary X-ray diffraction studies of ferredoxin reductase from Leptospira interrogans

    International Nuclear Information System (INIS)

    Crystals adequate for X-ray diffraction analysis have been prepared from L. interrogans ferredoxin-NADP+ reductase. Ferredoxin-NADP+ reductase (FNR) is an FAD-containing enzyme that catalyzes electron transfer between NADP(H) and ferredoxin. Here, results are reported of the recombinant expression, purification and crystallization of FNR from Leptospira interrogans, a parasitic bacterium of animals and humans. The L. interrogans FNR crystals belong to a primitive monoclinic space group and diffract to 2.4 Å resolution at a synchrotron source

  13. Cloning, Expression, and Purification of Histidine-Tagged Escherichia coli Dihydrodipicolinate Reductase

    OpenAIRE

    Trigoso, Yvonne D.; Russell C Evans; Karsten, William E.; Lilian Chooback

    2016-01-01

    The enzyme dihydrodipicolinate reductase (DHDPR) is a component of the lysine biosynthetic pathway in bacteria and higher plants. DHDPR catalyzes the NAD(P)H dependent reduction of 2,3-dihydrodipicolinate to the cyclic imine L-2,3,4,5,-tetrahydropicolinic acid. The dapB gene that encodes dihydrodipicolinate reductase has previously been cloned, but the expression of the enzyme is low and the purification is time consuming. Therefore the E. coli dapB gene was cloned into the pET16b vector to i...

  14. Avicequinone C Isolated from Avicennia marina Exhibits 5α-Reductase-Type 1 Inhibitory Activity Using an Androgenic Alopecia Relevant Cell-Based Assay System

    Directory of Open Access Journals (Sweden)

    Ruchy Jain

    2014-05-01

    Full Text Available Avicennia marina (AM exhibits various biological activities and has been traditionally used in Egypt to cure skin diseases. In this study, the methanolic heartwood extract of AM was evaluated for inhibitory activity against 5α-reductase (5α-R [E.C.1.3.99.5], the enzyme responsible for the over-production of 5α-dihydrotestosterone (5α-DHT causing androgenic alopecia (AGA. An AGA-relevant cell-based assay was developed using human hair dermal papilla cells (HHDPCs, the main regulator of hair growth and the only cells within the hair follicle that are the direct site of 5α-DHT action, combined with a non-radioactive thin layer chromatography (TLC detection technique. The results revealed that AM is a potent 5α-R type 1 (5α-R1 inhibitor, reducing the 5α-DHT production by 52% at the final concentration of 10 µg/mL. Activity-guided fractionation has led to the identification of avicequinone C, a furanonaphthaquinone, as a 5α-R1 inhibitor with an IC50 of 9.94 ± 0.33 µg/mL or 38.8 ± 1.29 µM. This paper is the first to report anti-androgenic activity through 5α-R1 inhibition of AM and avicequinone C.

  15. Avicequinone C isolated from Avicennia marina exhibits 5α-reductase-type 1 inhibitory activity using an androgenic alopecia relevant cell-based assay system.

    Science.gov (United States)

    Jain, Ruchy; Monthakantirat, Orawan; Tengamnuay, Parkpoom; De-Eknamkul, Wanchai

    2014-01-01

    Avicennia marina (AM) exhibits various biological activities and has been traditionally used in Egypt to cure skin diseases. In this study, the methanolic heartwood extract of AM was evaluated for inhibitory activity against 5α-reductase (5α-R) [E.C.1.3.99.5], the enzyme responsible for the over-production of 5α-dihydrotestosterone (5α-DHT) causing androgenic alopecia (AGA). An AGA-relevant cell-based assay was developed using human hair dermal papilla cells (HHDPCs), the main regulator of hair growth and the only cells within the hair follicle that are the direct site of 5α-DHT action, combined with a non-radioactive thin layer chromatography (TLC) detection technique. The results revealed that AM is a potent 5α-R type 1 (5α-R1) inhibitor, reducing the 5α-DHT production by 52% at the final concentration of 10 µg/mL. Activity-guided fractionation has led to the identification of avicequinone C, a furanonaphthaquinone, as a 5α-R1 inhibitor with an IC50 of 9.94 ± 0.33 µg/mL or 38.8 ± 1.29 µM. This paper is the first to report anti-androgenic activity through 5α-R1 inhibition of AM and avicequinone C. PMID:24858268

  16. Two crystal structures of dihydrofolate reductase-thymidylate synthase from Cryptosporidium hominis reveal protein–ligand interactions including a structural basis for observed antifolate resistance

    International Nuclear Information System (INIS)

    An analysis of the protein–ligand interactions in two crystal structures of DHFR-TS from C. hominis reveals a possible structural basis for observed antifolate resistance in C. hominis DHFR. A comparison with the structure of human DHFR reveals residue substitutions that may be exploited for the design of species-selective inhibitors. Cryptosporidium hominis is a protozoan parasite that causes acute gastrointestinal illness. There are no effective therapies for cryptosporidiosis, highlighting the need for new drug-lead discovery. An analysis of the protein–ligand interactions in two crystal structures of dihydrofolate reductase-thymidylate synthase (DHFR-TS) from C. hominis, determined at 2.8 and 2.87 Å resolution, reveals that the interactions of residues Ile29, Thr58 and Cys113 in the active site of C. hominis DHFR provide a possible structural basis for the observed antifolate resistance. A comparison with the structure of human DHFR reveals active-site differences that may be exploited for the design of species-selective inhibitors

  17. Elevated CO2-induced production of nitric oxide (NO) by NO synthase differentially affects nitrate reductase activity in Arabidopsis plants under different nitrate supplies.

    Science.gov (United States)

    Du, Shaoting; Zhang, Ranran; Zhang, Peng; Liu, Huijun; Yan, Minggang; Chen, Ni; Xie, Huaqiang; Ke, Shouwei

    2016-02-01

    CO2 elevation often alters the plant's nitrate reductase (NR) activity, the first enzyme acting in the nitrate assimilation pathway. However, the mechanism underlying this process remains unknown. The association between elevated CO2-induced alterations of NR activity and nitric oxide (NO) was examined in Col-0 Arabidopsis fed with 0.2-10 mM nitrate, using NO donors, NO scavenger, and NO synthase (NOS) inhibitor. The noa1 mutant, in which most NOS activity was lost, and the NR activity-null mutant nia1 nia2 were also used to examine the above association. In response to CO2 elevation, NR activity increased in low-nitrate Col-0 plants but was inhibited in high-nitrate Col-0 plants. NO scavenger and NOS inhibitor could eliminate these two responses, whereas the application of NO donors mimicked these distinct responses in ambient CO2-grown Col-0 plants. Furthermore, in both low- and high-nitrate conditions, elevated CO2 increased NOS activity and NO levels in Col-0 and nia1 nia2 plants but had little effect on NO level and NR activity in noa1 plants. Considering all of these findings, this study concluded that, in response to CO2 elevation, either the NR activity induction in low-nitrate plants or the NR activity inhibition in high-nitrate plants is regulated by NOS-generated NO. PMID:26608644

  18. Novel Substrate Specificity and Temperature-Sensitive Activity of Mycosphaerella graminicola CYP51 Supported by the Native NADPH Cytochrome P450 Reductase.

    Science.gov (United States)

    Price, Claire L; Warrilow, Andrew G S; Parker, Josie E; Mullins, Jonathan G L; Nes, W David; Kelly, Diane E; Kelly, Steven L

    2015-05-15

    Mycosphaerella graminicola (Zymoseptoria tritici) is an ascomycete filamentous fungus that causes Septoria leaf blotch in wheat crops. In Europe the most widely used fungicides for this major disease are demethylation inhibitors (DMIs). Their target is the essential sterol 14α-demethylase (CYP51), which requires cytochrome P450 reductase (CPR) as its redox partner for functional activity. The M. graminicola CPR (MgCPR) is able to catalyze the sterol 14α-demethylation of eburicol and lanosterol when partnered with Candida albicans CYP51 (CaCYP51) and that of eburicol only with M. graminicola CYP51 (MgCYP51). The availability of the functional in vivo redox partner enabled the in vitro catalytic activity of MgCYP51 to be demonstrated for the first time. MgCYP51 50% inhibitory concentration (IC50) studies with epoxiconazole, tebuconazole, triadimenol, and prothioconazole-desthio confirmed that MgCYP51 bound these azole inhibitors tightly. The characterization of the MgCPR/MgCYP51 redox pairing has produced a functional method to evaluate the effects of agricultural azole fungicides, has demonstrated eburicol specificity in the activity observed, and supports the conclusion that prothioconazole is a profungicide. PMID:25746994

  19. Pinpointing a Mechanistic Switch Between Ketoreduction and “Ene” Reduction in Short‐Chain Dehydrogenases/Reductases

    Science.gov (United States)

    Lygidakis, Antonios; Karuppiah, Vijaykumar; Hoeven, Robin; Ní Cheallaigh, Aisling; Leys, David; Gardiner, John M.; Toogood, Helen S.

    2016-01-01

    Abstract Three enzymes of the Mentha essential oil biosynthetic pathway are highly homologous, namely the ketoreductases (−)‐menthone:(−)‐menthol reductase and (−)‐menthone:(+)‐neomenthol reductase, and the “ene” reductase isopiperitenone reductase. We identified a rare catalytic residue substitution in the last two, and performed comparative crystal structure analyses and residue‐swapping mutagenesis to investigate whether this determines the reaction outcome. The result was a complete loss of native activity and a switch between ene reduction and ketoreduction. This suggests the importance of a catalytic glutamate vs. tyrosine residue in determining the outcome of the reduction of α,β‐unsaturated alkenes, due to the substrate occupying different binding conformations, and possibly also to the relative acidities of the two residues. This simple switch in mechanism by a single amino acid substitution could potentially generate a large number of de novo ene reductases. PMID:27411040

  20. Sorbitol determination by liquid chromatography: application to red blood cells of diabetic rats.

    Science.gov (United States)

    Akanuma, H; Yamanouchi, T; Ono, H; Nomura, K; Akanuma, Y

    1985-02-01

    This report describes an application of liquid chromatography to the determination of sorbitol in red blood cells. The chromatograph employed in the present study was made up of sub- and main-separation systems and a detector portion. The sub-separation system was for concentration of polyols and involved two small columns, each containing the same anion exchange resin. The first was a tiny column which, in borate form, served as the concentrator of polyols and sugars charged in a large volume, while the second, in acetate form, separated the carbohydrates from the borate. The main system was for the fine separation of each carbohydrate and employed cation exchange columns. The detector part utilized a flow fluorometric method comprising two successive reactions: periodate oxidation followed by the Hantzsch reaction. The resulting whole chromatographic system was applied to the determination of sorbitol in red blood cells obtained from normal rats and rats made diabetic by the administration of streptozotocin; a part of the latter group had also received an aldose reductase inhibitor. Our results supported the concepts that a prolonged duration of high blood glucose level induces an elevated level of sorbitol inside red blood cells and that aldose reductase inhibitors are effective in reducing this level. PMID:3924905