Kinetic analysis of site-directed mutants of methionine synthase from Candida albicans

International Nuclear Information System (INIS)

Prasannan, Priya; Suliman, Huda S.; Robertus, Jon D.

2009-01-01

Fungal methionine synthase catalyzes the transfer of a methyl group from 5-methyl-tetrahydrofolate to homocysteine to create methionine. The enzyme, called Met6p in fungi, is required for the growth of the pathogen Candida albicans, and is consequently a reasonable target for antifungal drug design. In order to understand the mechanism of this class of enzyme, we created a three-dimensional model of the C. albicans enzyme based on the known structure of the homologous enzyme from Arabidopsis thaliana. A fusion protein was created and shown to have enzyme activity similar to the wild-type Met6p. Fusion proteins containing mutations at eight key sites were expressed and assayed in this background. The D614 carboxylate appears to ion pair with the amino group of homocysteine and is essential for activity. Similarly, D504 appears to bind to the polar edge of the folate and is also required for activity. Other groups tested have lesser roles in substrate binding and catalysis.

Constitutive expression of feedback-insensitive cystathionine γ-synthase increases methionine levels in soybean leaves and seeds

Institute of Scientific and Technical Information of China (English)

YU Yang; HOU Wen-sheng; YaeI Hacham; SUN Shi; WU Cun-xiang; Ifat Matityahu; SONG Shikui; RacheI Amir; HAN Tian-fu

2018-01-01

Soybean (Glycine max (L.) Merr.) is a major crop that provides plant-origin protein and oil for humans and livestock. Although the soybean vegetative tissues and seeds provide a major source of high-quality protein, they suffer from low concentration of an essential sulfur-containing amino acid, methionine, which significantly limits their nutritional quality. The level of methionine is mainly controlled by the first unique enzyme of methionine synthesis, cystathione γ-synthase (CGS). Aiming to elevate methionine level in vegetative tissues and seeds, we constitutively over-expressed a feedback-insensitive Arabidopsis CGS (AtD-CGS) in soybean cultivars, Zigongdongdou (ZD) and Jilinxiaoli 1 (JX). The levels of soluble methionine increased remarkably in leaves of transgenic soybeans compared to wild-type plants (6.6- and 7.3-fold in two transgenic ZD lines, and 3.7-fold in one transgenic JX line). Furthermore, the total methionine contents were significantly increased in seeds of the transgenic ZD lines (1.5- to 4.8-fold increase) and the transgenic JX lines (1.3- to 2.3-fold increase) than in the wild type. The protein contents of the transgenic soybean seeds were significantly elevated compared to the wild type, suggesting that the scarcity of methionine in soybeans may limit protein accumulation in soybean seeds. The increased protein content did not alter the profile of major storage proteins in the seeds. Generally, this study provides a promising strategy to increase the levels of methionine and protein in soybean through the breeding programs.

Possible Involvement of Hydrosulfide in B12-Dependent Methyl Group Transfer

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John I. Toohey

2017-04-01

Full Text Available Evidence from several fields of investigation lead to the hypothesis that the sulfur atom is involved in vitamin B12-dependent methyl group transfer. To compile the evidence, it is necessary to briefly review the following fields: methylation, the new field of sulfane sulfur/hydrogen sulfide (S°/H2S, hydrosulfide derivatives of cobalamins, autoxidation of hydrosulfide radical, radical S-adenosylmethionine methyl transfer (RSMT, and methionine synthase (MS. Then, new reaction mechanisms for B12-dependent methyl group transfer are proposed; the mechanisms are facile and overcome difficulties that existed in previously-accepted mechanisms. Finally, the theory is applied to the effect of S°/H2S in nerve tissue involving the “hypomethylation theory” that was proposed 50 years ago to explain the neuropathology resulting from deficiency of vitamin B12 or folic acid. The conclusions are consistent with emerging evidence that sulfane sulfur/hydrogen sulfide may be beneficial in treating Alzheimer’s disease.

Cobalamin and haptocorrin in human milk and cobalamin-related variables in mother and child

DEFF Research Database (Denmark)

Greibe, Eva; Lildballe, Dorte L; við Streym, Susanna

2013-01-01

BACKGROUND: Measurement of milk cobalamin is hampered by the high content of the cobalamin-binding protein haptocorrin, and limited data are available relating trustworthy measures of milk cobalamin to cobalamin status in healthy mothers and their children. OBJECTIVES: The objectives were to expl...

A patient with an inborn error of vitamin B12 metabolism (cblF) detected by newborn screening.

Science.gov (United States)

Armour, Christine M; Brebner, Alison; Watkins, David; Geraghty, Michael T; Chan, Alicia; Rosenblatt, David S

2013-07-01

A neonate, who was found to have an elevated C3/C2 ratio and minimally elevated propionylcarnitine on newborn screening, was subsequently identified as having the rare cblF inborn error of vitamin B12 (cobalamin) metabolism. This disorder is characterized by the retention of unmetabolized cobalamin in lysosomes such that it is not readily available for cellular metabolism. Although cultured fibroblasts from the patient did not show the expected functional abnormalities of the cobalamin-dependent enzymes, methylmalonyl-CoA mutase and methionine synthase, they did show reduced synthesis of the active cobalamin cofactors adenosylcobalamin and methylcobalamin. Mutation analysis of LMBRD1 established that the patient had the cblF disorder. Treatment was initiated promptly, and the patient showed a robust response to regular injections of cyanocobalamin, and she was later switched to hydroxocobalamin. Currently, at 3 years of age, the child is clinically well, with appropriate development. Adjusted newborn screening cutoffs in Ontario allowed detection of a deficiency that might not have otherwise been identified, allowing early treatment and perhaps preventing the adverse sequelae seen in some untreated patients.

The [4Fe-4S](2+) cluster in reconstituted biotin synthase binds S-adenosyl-L-methionine.

Science.gov (United States)

Cosper, Michele Mader; Jameson, Guy N L; Davydov, Roman; Eidsness, Marly K; Hoffman, Brian M; Huynh, Boi Hanh; Johnson, Michael K

2002-11-27

The combination of resonance Raman, electron paramagnetic resonance and Mössbauer spectroscopies has been used to investigate the effect of S-adenosyl-l-methionine (SAM) on the spectroscopic properties of the [4Fe-4S]2+ cluster in biotin synthase. The results indicate that SAM interacts directly at a unique iron site of the [4Fe-4S]2+ cluster in BioB and support the hypothesis of a common inner-sphere mechanism for the reductive cleavage of SAM in the radical SAM family of Fe-S enzymes.

Metformin Lowers Serum Cobalamin without Changing Other Markers of Cobalamin Status: A Study on Women with Polycystic Ovary Syndrome

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Ebba Nexo

2013-07-01

Full Text Available Treatment with the anti-diabetic drug metformin is followed by a decline in plasma cobalamin, but it is unsettled whether this denotes an impaired cobalamin status. This study has explored changes in the markers of cobalamin status in women with Polycystic Ovary Syndrome treated with metformin (1.5–2.5 g per day (n = 29 or placebo (n = 23 for six months. Serum samples were collected before and after two, four, and six months of treatment. We found serum cobalamin to decline and reach significant lower levels after six months of treatment (p = 0.003. Despite the decline in serum cobalamin, we observed no reductions in the physiological active part of cobalamin bound to transcobalamin (holotranscobalamin, or increase in the metabolic marker of cobalamin status, methylmalonic acid. Instead, the non-functional part of circulating cobalamin bound to haptocorrin declined (p = 0.0009. Our results have two implications: The data questions whether metformin treatment induces an impaired cobalamin status in PCOS patients, and further suggests that serum cobalamin is a futile marker for judging cobalamin status in metformin-treated patients.

Cobalamin Deficiency in Elderly Patients: A Personal View

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Emmanuel Andrès

2008-01-01

Full Text Available Cobalamin (vitamin B12 deficiency is particularly common in the elderly (>65 years of age but is often unrecognized because its clinical manifestations are subtle; however, they are also potentially serious, particularly from a neuropsychiatric and hematological perspective. In the elderly, the main causes of cobalamin deficiency are pernicious anemia and food-cobalamin malabsorption. Food-cobalamin malabsorption syndrome is a disorder characterized by the inability to release cobalamin from food or its binding proteins. This syndrome is usually caused by atrophic gastritis, related or unrelated to Helicobacter pylori infection, and long-term ingestion of antacids and biguanides. Management of cobalamin deficiency with cobalamin injections is currently well documented but new routes of cobalamin administration (oral and nasal are being studied, especially oral cobalamin therapy for food-cobalamin malabsorption.

Clinical aspects of cobalamin deficiency in elderly patients. Epidemiology, causes, clinical manifestations, and treatment with special focus on oral cobalamin therapy.

Science.gov (United States)

Andrès, Emmanuel; Vidal-Alaball, Josep; Federici, Laure; Loukili, Noureddine Henoun; Zimmer, Jacques; Kaltenbach, Georges

2007-10-01

The aim of this work was to review the literature concerning cobalamin deficiency in elderly patients. Articles were identified through searches of PubMed-MEDLINE (January 1990 to June 2006), restricted to: English and French language, human subjects, elderly patients (>65 years), clinical trial, review and guidelines. Additional unpublished data from our cohort with cobalamin deficiency at the University Hospital of Strasbourg, France, were also considered. All of the papers and abstracts were reviewed by at least two senior researchers who selected the data used in the study. In elderly people, the main causes of cobalamin deficiency are pernicious anemia and food-cobalamin malabsorption. The recently identified food-cobalamin malabsorption syndrome is a disorder characterized by the inability to release cobalamin from food or from its binding proteins. This syndrome is usually the consequence of atrophic gastritis, related or not to Helicobacter pylori infection, and of the long-term ingestion of antacids and biguanides (in around 60% of the patients). Management of cobalamin deficiency has been well established with the use of cobalamin injections. However, new routes of cobalamin administration (oral and nasal) are currently being developed, especially the use of oral cobalamin therapy to treat food-cobalamin malabsorption.

Cobalamin analogues in humans

DEFF Research Database (Denmark)

Hardlei, Tore Forsingdal; Obeid, Rima; Herrmann, Wolfgang

2013-01-01

BACKGROUND: Haptocorrin (HC) carries cobalamin analogues (CorA), but whether CorA are produced in the body is unknown. All cobalamins (Cbl) to the foetus are delivered by the Cbl-specific protein transcobalamin (TC), and therefore analysis of cord serum for CorA may help to clarify the origin...

Importance of methionine biosynthesis for Arabidopsis seed germination and seedling growth

NARCIS (Netherlands)

Gallardo, K.; Job, C.; Groot, S.P.C.; Puype, M.; Demol, H.; VandeKerckhove, J.; Job, D.

2002-01-01

Proteomics of Arabidopsis seeds revealed the differential accumulation during germination of two housekeeping enzymes. The first corresponded to methionine synthase that catalyses the last step in the plant methionine biosynthetic pathway. This protein was present at low level in dry mature seeds,

How environmental and genetic factors combine to cause autism: A redox/methylation hypothesis.

Science.gov (United States)

Deth, Richard; Muratore, Christina; Benzecry, Jorge; Power-Charnitsky, Verna-Ann; Waly, Mostafa

2008-01-01

Recently higher rates of autism diagnosis suggest involvement of environmental factors in causing this developmental disorder, in concert with genetic risk factors. Autistic children exhibit evidence of oxidative stress and impaired methylation, which may reflect effects of toxic exposure on sulfur metabolism. We review the metabolic relationship between oxidative stress and methylation, with particular emphasis on adaptive responses that limit activity of cobalamin and folate-dependent methionine synthase. Methionine synthase activity is required for dopamine-stimulated phospholipid methylation, a unique membrane-delimited signaling process mediated by the D4 dopamine receptor that promotes neuronal synchronization and attention, and synchrony is impaired in autism. Genetic polymorphisms adversely affecting sulfur metabolism, methylation, detoxification, dopamine signaling and the formation of neuronal networks occur more frequently in autistic subjects. On the basis of these observations, a "redox/methylation hypothesis of autism" is described, in which oxidative stress, initiated by environment factors in genetically vulnerable individuals, leads to impaired methylation and neurological deficits secondary to reductions in the capacity for synchronizing neural networks.

Metformin Lowers Serum Cobalamin without Changing Other Markers of Cobalamin Status: A Study on Women with Polycystic Ovary Syndrome

DEFF Research Database (Denmark)

Greibe, Eva; Trolle, G. Birgitta; Bor, Mustafa Vakur

2013-01-01

Treatment with the anti-diabetic drug metformin is followed by a decline in plasma cobalamin, but it is unsettled whether this denotes an impaired cobalamin status. This study has explored changes in the markers of cobalamin status in women with Polycystic Ovary Syndrome treated with metformin (1...

Cobalamin and its binding protein in rat milk

DEFF Research Database (Denmark)

Raaberg, Lasse; Nexø, Ebba; Poulsen, Steen Seier

1989-01-01

Cobalamin and its binding protein, haptocorrin, are present in rat milk throughout the lactation period. The concentration of cobalamin is approximately 0.3-times the concentration of the unsaturated binding protein. The concentration of the unsaturated cobalamin-binding protein varies between 18...

Structural and functional characteristics of cGMP-dependent methionine oxidation in Arabidopsis thaliana proteins

KAUST Repository

Marondedze, Claudius

2013-01-05

Background: Increasing structural and biochemical evidence suggests that post-translational methionine oxidation of proteins is not just a result of cellular damage but may provide the cell with information on the cellular oxidative status. In addition, oxidation of methionine residues in key regulatory proteins, such as calmodulin, does influence cellular homeostasis. Previous findings also indicate that oxidation of methionine residues in signaling molecules may have a role in stress responses since these specific structural modifications can in turn change biological activities of proteins. Findings. Here we use tandem mass spectrometry-based proteomics to show that treatment of Arabidopsis thaliana cells with a non-oxidative signaling molecule, the cell-permeant second messenger analogue, 8-bromo-3,5-cyclic guanosine monophosphate (8-Br-cGMP), results in a time-dependent increase in the content of oxidised methionine residues. Interestingly, the group of proteins affected by cGMP-dependent methionine oxidation is functionally enriched for stress response proteins. Furthermore, we also noted distinct signatures in the frequency of amino acids flanking oxidised and un-oxidised methionine residues on both the C- and N-terminus. Conclusions: Given both a structural and functional bias in methionine oxidation events in response to a signaling molecule, we propose that these are indicative of a specific role of such post-translational modifications in the direct or indirect regulation of cellular responses. The mechanisms that determine the specificity of the modifications remain to be elucidated. 2013 Marondedze et al.; licensee BioMed Central Ltd.

Association of Human Methionine Synthase-A2756G Transition With Prostate Cancer: A Case-Control Study and in Silico Analysis

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Arezou Ebrahimi

2017-07-01

Full Text Available Methionine synthase (MTR is one of the key enzymes of folate pathway, which play a key role in the construction, repair, and methylation of DNA. In this study, an association of MTR A2756G gene transition with prostate cancer in men populations of Kashan-Iran was investigated by a case-control study and an in silico analysis. The 200 samples including 100 patients with prostate cancer, as case group and 100 healthy men, as control group included in this study. MTR-A2756G genotyping was performed by PCR-RFLP technique. Some in silico tools used to evaluate the effects of A2756G transition on the structure and function of MTR. Results showed that the AG genotype (OR: 2.4014, 95% CI: 1.3216-4.3636, P=0.0040, and GG genotype (OR: 3.6324, 95% CI: 1.2629-10.4475, P=0.0167 and G allele (OR: 2.0120, 95% CI: 1.3098-3.0905, P=0.0014 were associated with prostate cancer. In silico analysis showed that polymorphisms of the enzyme protein might change properties of MTR such as relative mutability and flexibility, which leads to alteration of stability and function of the enzyme. Based on the results, an MTR-A2756G polymorphism which changes activity and stability of the methionine synthase associated with prostate cancer in men. It is a preliminary study and is presenting data for future comprehensive study for making a clinical conclusion that this gene transition is a biomarker for susceptibility to prostate cancer.

Oral cobalamin supplementation in cats with hypocobalaminaemia: a retrospective study.

Science.gov (United States)

Toresson, Linda; Steiner, Joerg M; Olmedal, Gunilla; Larsen, MajBritt; Suchodolski, Jan S; Spillmann, Thomas

2017-12-01

Objectives The objective of the study was to evaluate whether oral cobalamin supplementation can restore normocobal-aminaemia in cats with hypocobalaminaemia and clinical signs of gastrointestinal disease. Methods This was a retrospective study based on a computerised database search for client-owned cats treated at Evidensia Specialist Animal Hospital, Helsingborg, Sweden, during the period December 2013 to August 2016. Inclusion criteria were cats with clinical signs of chronic enteropathy, an initial serum cobalamin concentration ⩽250 pmol/l (reference interval 214-738 pmol/l) and oral treatment with cobalamin tablets. Results Twenty-five cats met the inclusion criteria. The cats were treated with 0.25 mg cyanocobalamin tablets once daily. Serum cobalamin concentration was rechecked 27-94 days after continuous oral cobalamin supplementation. All cats had serum cobalamin concentrations above the reference interval after oral cobalamin supplementation. Median (range) serum cobalamin concentration was 128 pmol/l (111-250 pmol/l) prior to treatment and 2701 pmol/l (738-16,359 pmol/l) after supplementation. This difference was statistically significant ( P cats with hypocobalaminaemia. Thus, oral cobalamin supplementation is a promising alternative to parenteral administration. Prospective comparative studies in cats being treated with parenteral vs oral cobalamin supplementation in a larger number of patients are warranted before oral supplementation can be recommended for routine use.

Methionine metabolism after portacaval shunt in the rat

International Nuclear Information System (INIS)

Benjamin, L.E.; Steele, R.D.

1985-01-01

The effect of portacaval shunt (PCS) on methionine metabolism in the rat was investigated. Male Sprague-Dawley rats were subjected to PCS and maintained on an 18% casein diet. Growth curves of operated rats were similar to controls. PCS rats excreted more urinary 35 SO 4 and less [ 35 S]taurine than controls after intraperitoneal injection of 0.3 mmol/100 g [ 35 S]methionine or [ 35 S]cysteine. Total urinary taurine excretion was similar in PCS and control rats after a methionine or cysteine load; however, under basal conditions PCS rats had higher urinary taurine levels than controls, indicating that PCS may cause the taurine pool to be expanded. Hepatic methionine, S-adenosylmethionine, and cysteine pools were significantly decreased in PCS rats, while S-adenosylhomocysteine levels were unchanged. Relative rates of transsulfuration in PCS and control rats were studied by following the decrease in the 3 H-to- 35 S ratio in liver protein after injection of [methyl-3H]methionine and [ 35 S]methionine, and no difference in flux of 35 S from [ 35 S]methionine to [ 35 S]cysteine was found. Similarly, total hepatic activities of methionine adenosyltransferase, cystathionine synthase, and cystathionine gamma-lyase were unchanged in PCS rats. These results indicate that altered methionine metabolism in PCS rats is not explained by changes in conversion of methionine to cysteine via the transsulfuration pathway

The Cobalamin-binding Protein in Zebrafish is an Intermediate Between the Three Cobalamin-binding Proteins in Human

DEFF Research Database (Denmark)

Greibe, Eva Holm; Fedosov, Sergey; Nexø, Ebba

2012-01-01

are the oldest evolutionary derivatives followed by IF and HC (the latter being present only in reptiles and most but not all mammals). Our findings suggest that the only cobalamin-binding protein in zebrafish is an intermediate between the three human cobalamin binders. These findings support the hypothesis...

Unexpected high plasma cobalamin

DEFF Research Database (Denmark)

Arendt, Johan F B; Nexo, Ebba

2013-01-01

It is well-established that more than 8% of patients examined for vitamin B12 deficiency unexpectedly have increased plasma levels of the vitamin, but so far there are no guidelines for the clinical interpretation of such findings. In this review, we summarise known associations between high plasma...... cobalamin binding proteins, transcobalamin and haptocorrin. Based on current knowledge, we suggest a strategy for the clinical interpretation of unexpected high plasma cobalamin. Since a number of the associated diseases are critical and life-threatening, the strategy promotes the concept of 'think...

Methylenetetrahydrofolate reductase 677C>T and methionine synthase 2756A>G mutations: no impact on survival, cognitive functioning, or cognitive decline in nonagenarians

DEFF Research Database (Denmark)

Bathum, Lise; von Bornemann Hjelmborg, Jacob; Christiansen, Lene

2007-01-01

BACKGROUND: Several reports have shown an association between homocysteine, cognitive functioning, and survival among the oldest-old. Two common polymorphisms in the genes coding for methylenetetrahydrofolate reductase (MTHFR 677C>T) and methionine synthase (MTR 2756A>G) have an impact on plasma...... homocysteine level. METHODS: We examined the effect of the MTHFR 677C>T and MTR 2756A>G genotypes on baseline cognitive functioning, cognitive decline over 5 years measured in three assessments, and survival in a population-based cohort of 1581 nonagenarians. Cognitive functioning was assessed by using...

89Zr-Cobalamin PET Tracer

DEFF Research Database (Denmark)

Kuda-Wedagedara, Akhila N W; Workinger, Jayme L; Nexo, Ebba

2017-01-01

Vitamin B12, or cobalamin (Cbl), is an essential nutrient. Acquisition, transport, and cellular internalization of Cbl are dependent on specific binding proteins and associated receptors. The circulating transport protein transcobalamin (TC) promotes cellular uptake via binding to specific......-Cbl (CN-Cbl). In vitro studies employing the CD320 receptor-positive breast cancer cell line MDA-MB-453 showed a 6- to 10-fold greater uptake of 89Zr-Cbl when compared with the uptake in the presence of 200-fold excess of CN-Cbl at 37 °C. We used nude mice with MDA-MB-453 tumors to study the feasibility...

Relationship between cobalamin deficiency and delirium in elderly patients undergoing cardiac surgery

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Sevuk U

2015-08-01

Full Text Available Utkan Sevuk,1 Erkan Baysal,2 Nurettin Ay,3 Yakup Altas,2 Rojhat Altindag,2 Baris Yaylak,2 Vahhac Alp,3 Ertan Demirtas4 1Department of Cardiovascular Surgery, Diyarbakir Gazi Yasargil Education and Research Hospital, Diyarbakir, 2Department of Cardiology, Diyarbakir Gazi Yasargil Education and Research Hospital, Diyarbakir, 3Department of General Surgery, Diyarbakir Gazi Yasargil Education and Research Hospital, Diyarbakir, 4Department of Cardiovascular Surgery, Liv Hospital, Ankara, Turkey Background: Delirium is common after cardiac surgery and is independently associated with increased morbidity, mortality, prolonged hospital stays, and higher costs. Cobalamin (vitamin B12 deficiency is a common cause of neuropsychiatric symptoms and affects up to 40% of elderly people. The relationship between cobalamin deficiency and the occurrence of delirium after cardiac surgery has not been examined in previous studies. We examined the relationship between cobalamin deficiency and delirium in elderly patients undergoing coronary artery bypass grafting (CABG surgery.Material and methods: A total of 100 patients with cobalamin deficiency undergoing CABG were enrolled in this retrospective study. Control group comprised 100 patients without cobalamin deficiency undergoing CABG. Patients aged 65 years or over were included. Diagnosis of delirium was made using Intensive Care Delirium Screening Checklist. Delirium severity was measured using the Delirium Rating Scale-revised-98.Results: Patients with cobalamin deficiency had a significantly higher incidence of delirium (42% vs 26%; P=0.017 and higher delirium severity scores (16.5±2.9 vs 15.03±2.48; P=0.034 than patients without cobalamin deficiency. Cobalamin levels were significantly lower in patients with delirium than patients without delirium (P=0.004. Delirium severity score showed a moderate correlation with cobalamin levels (Ρ=-0.27; P=0.024. Logistic regression analysis demonstrated that

Vitamin B12 Metabolism during Pregnancy and in Embryonic Mouse Models

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Maira A. Moreno-Garcia

2013-09-01

Full Text Available Vitamin B12 (cobalamin, Cbl is required for cellular metabolism. It is an essential coenzyme in mammals for two reactions: the conversion of homocysteine to methionine by the enzyme methionine synthase and the conversion of methylmalonyl-CoA to succinyl-CoA by the enzyme methylmalonyl-CoA mutase. Symptoms of Cbl deficiency are hematological, neurological and cognitive, including megaloblastic anaemia, tingling and numbness of the extremities, gait abnormalities, visual disturbances, memory loss and dementia. During pregnancy Cbl is essential, presumably because of its role in DNA synthesis and methionine synthesis; however, there are conflicting studies regarding an association between early pregnancy loss and Cbl deficiency. We here review the literature about the requirement for Cbl during pregnancy, and summarized what is known of the expression pattern and function of genes required for Cbl metabolism in embryonic mouse models.

Hyperammonaemic encephalopathy secondary to selective cobalamin deficiency in a juvenile Border collie.

Science.gov (United States)

Battersby, I A; Giger, U; Hall, E J

2005-07-01

An eight-month-old Border collie was presented with anorexia, cachexia, failure to thrive and stupor. Laboratory tests demonstrated a mild anaemia, neutropenia, proteinuria and hyperammonaemia. Serum bile acid concentrations were normal, but an ammonia tolerance test (ATT) was abnormal. The dog responded to symptomatic therapy for hepatoencephalopathy. When a low serum cobalamin (vitamin B12) concentration and methylmalonic aciduria were noted, the dog was given a supplement of parenteral cobalamin. Two weeks later, a repeat ATT was normal. Cobalamin supplementation was continued every two weeks, and all clinical signs, except for proteinuria, resolved despite withdrawing all therapy for hepatoencephalopathy. A presumptive diagnosis of hereditary selective cobalamin malabsorption was made, based on the young age, Border collie breed, low serum cobalamin concentration and methylmalonic aciduria. Although hereditary selective cobalamin malabsorption in Border collies, giant schnauzers, Australian shepherd dogs and beagles has previously been reported in North America, to the authors' knowledge this is the first report of the condition in the UK and the first to document an abnormal ATT in a cobalamin-deficient dog.

A Single Rainbow Trout Cobalamin-binding Protein Stands in for Three Human Binders

DEFF Research Database (Denmark)

Greibe, Eva Holm; Fedosov, Sergey; Sorensen, Boe S

2012-01-01

affinity for the cobalamin analog cobinamide. Like haptocorrin and transcobalamin, the trout cobalamin-binding protein was present in plasma and recognized ligands with altered nucleotide moiety. Like intrinsic factors, the trout cobalamin-binding protein was present in the stomach and resisted degradation...... by trypsin and chymotrypsin. It also resembled intrinsic factor in the composition of conserved residues in the primary cobalamin-binding site in the C terminus. The trout cobalamin-binding protein was glycosylated and displayed spectral properties comparable with those of haptocorrin and intrinsic factor...

Functional Genomics and Phylogenetic Evidence Suggest Genus-Wide Cobalamin Production by the Globally Distributed Marine Nitrogen Fixer Trichodesmium.

Science.gov (United States)

Walworth, Nathan G; Lee, Michael D; Suffridge, Christopher; Qu, Pingping; Fu, Fei-Xue; Saito, Mak A; Webb, Eric A; Sañudo-Wilhelmy, Sergio A; Hutchins, David A

2018-01-01

Only select prokaryotes can biosynthesize vitamin B 12 (i.e., cobalamins), but these organic co-enzymes are required by all microbial life and can be vanishingly scarce across extensive ocean biomes. Although global ocean genome data suggest cyanobacteria to be a major euphotic source of cobalamins, recent studies have highlighted that >95% of cyanobacteria can only produce a cobalamin analog, pseudo-B 12 , due to the absence of the BluB protein that synthesizes the α ligand 5,6-dimethylbenzimidizole (DMB) required to biosynthesize cobalamins. Pseudo-B 12 is substantially less bioavailable to eukaryotic algae, as only certain taxa can intracellularly remodel it to one of the cobalamins. Here we present phylogenetic, metagenomic, transcriptomic, proteomic, and chemical analyses providing multiple lines of evidence that the nitrogen-fixing cyanobacterium Trichodesmium transcribes and translates the biosynthetic, cobalamin-requiring BluB enzyme. Phylogenetic evidence suggests that the Trichodesmium DMB biosynthesis gene, bluB , is of ancient origin, which could have aided in its ecological differentiation from other nitrogen-fixing cyanobacteria. Additionally, orthologue analyses reveal two genes encoding iron-dependent B 12 biosynthetic enzymes (cbiX and isiB), suggesting that iron availability may be linked not only to new nitrogen supplies from nitrogen fixation, but also to B 12 inputs by Trichodesmium . These analyses suggest that Trichodesmium contains the genus-wide genomic potential for a previously unrecognized role as a source of cobalamins, which may prove to considerably impact marine biogeochemical cycles.

A role for 11C-methionine PET imaging in ACTH-dependent Cushing's syndrome.

Science.gov (United States)

Koulouri, Olympia; Steuwe, Andrea; Gillett, Daniel; Hoole, Andrew C; Powlson, Andrew S; Donnelly, Neil A; Burnet, Neil G; Antoun, Nagui M; Cheow, Heok; Mannion, Richard J; Pickard, John D; Gurnell, Mark

2015-10-01

We report our experience of functional imaging with (11)C-methionine positron emission tomography-computed tomography (PET-CT) co-registered with 3D gradient echo (spoiled gradient recalled (SPGR)) magnetic resonance imaging (MRI) in the investigation of ACTH-dependent Cushing's syndrome. Twenty patients with i) de novo Cushing's disease (CD, n=10), ii) residual or recurrent hypercortisolism following first pituitary surgery (±radiotherapy; n=8) or iii) ectopic Cushing's syndrome (n=2) were referred to our centre for functional imaging studies between 2010 and 2015. Six of the patients with de novo CD and five of those with persistent/relapsed disease had a suspected abnormality on conventional MRI. All patients underwent (11)C-methionine PET-CT. For pituitary imaging, co-registration of PET-CT images with contemporaneous SPGR MRI (1 mm slice thickness) was performed, followed by detailed mapping of (11)C-methionine uptake across the sella in three planes (coronal, sagittal and axial). This allowed us to determine whether suspected adenomas seen on structural imaging exhibited focal tracer uptake on functional imaging. In seven of ten patients with de novo CD, asymmetric (11)C-methionine uptake was observed within the sella, which co-localized with the suspected site of a corticotroph microadenoma visualised on SPGR MRI (and which was subsequently confirmed histologically following successful transsphenoidal surgery (TSS)). Focal (11)C-methionine uptake that correlated with a suspected abnormality on pituitary MRI was seen in five of eight patients with residual or recurrent Cushing's syndrome following first TSS (and pituitary radiotherapy in two cases). Two patients elected to undergo repeat TSS with histology confirming a corticotroph tumour in each case. In two patients with the ectopic ACTH syndrome, (11)C-methionine was concentrated in sites of distant metastases, with minimal uptake in the sellar region. (11)C-methionine PET-CT can aid the detection of

Free and protein-bound cobalamin absorption in healthy middle-aged and older subjects.

Science.gov (United States)

van Asselt, D Z; van den Broek, W J; Lamers, C B; Corstens, F H; Hoefnagels, W H

1996-08-01

To study free- and protein-bound cobalamin absorption and the correlation with atrophic gastritis in healthy middle-aged and older subjects. A cross-sectional study. Fifty-two healthy subjects, aged 26 to 87 years, apparently free from conditions known to influence the cobalamin status. Middle-aged subjects were defined as those younger than 65 years of age (median age 57 years) and older subjects as those 65 years and older (median age 75 years). Protein-bound cobalamin absorption was assessed by 48-hour urinary excretion method following oral administration of scrambled egg yolk, labeled in vivo with 57 Co-cobalamin by injecting a hen with 57 Co-cyanocobalamin. The percentage of 57 Co-cobalamin bound to protein was 65%. Free cobalamin absorption was assessed by 48-hour urinary excretion method following oral administration of crystalline 57 Co-cyanocobalamin. Plasma cobalamin, folate and fasting plasma gastrin, and pepsinogen A and C concentrations were determined. The median urinary excretion of egg yolk 57 Co-cobalamin in middle-aged subjects was 12.3% (25th and 75th percentiles 10.5%-14.5%) compared with 11.7% (25th and 75th percentiles 9.8%-13.6%) in older subjects (P = .283). The median urinary excretion after administration of free 57 Co-cobalamin in middle-aged subjects was 25.7% (25th and 75th percentiles 20.6%-30.7%) compared with 27.9% (25th and 75th percentiles 21.4%-34.5%) in older subjects (P = .694). Neither egg yolk nor free 57 Co-cobalamin excretion correlated with age. A ratio of pepsinogen A to pepsinogen C less than 1.6, indicating atrophic gastritis, was found in 13 subjects. Within the atrophic gastritis group, 11 subjects had a pepsinogen A concentration greater than or equal to 17 micrograms/L, indicating mild to moderate atrophic gastritis, and two subjects had a pepsinogen A concentration less than 17 micrograms/L, indicating severe atrophic gastritis or gastric atrophy. All subjects had normal fasting plasma gastrin concentrations. Free

Cobalt-vitamin B12 deficiency and the activity of methylmalonyl CoA mutase and methionine synthase in cattle.

Science.gov (United States)

Kennedy, D G; Young, P B; Kennedy, S; Scott, J M; Molloy, A M; Weir, D G; Price, J

1995-01-01

Cobalt deficiency was induced in cattle by feeding two groups of animals either a basal diet that was very low in Co (12.9-17.6 micrograms Co per kg), or the same diet supplemented with cobalt, for a total of 64 weeks. Vitamin B12 deficiency was induced, as judged by hepatic concentrations of vitamin B12 and plasma concentrations of MMA. However, the activity of holo-methylmalonyl CoA mutase was significantly reduced only in brain. This was reflected in very minor alterations in the tissue concentrations of branched chain- and odd numbered-fatty acids. The activity of holo-methionine synthase was significantly reduced in liver and brain, but there were no consequent alterations in the concentrations of phosphatidyl choline and phosphatidyl ethanolamine. This study confirms that cattle are less susceptible to the effects of cobalt deficiency than sheep, and concludes that prolonged cobalt deficiency had little significant effect on tissue metabolism.

Structural and functional characteristics of cGMP-dependent methionine oxidation in Arabidopsis thaliana proteins

KAUST Repository

Marondedze, Claudius; Turek, Ilona; Parrott, Brian Jonathan; Thomas, Ludivine; Jankovic, Boris R.; Lilley, Kathryn S; Gehring, Christoph A

2013-01-01

molecule, the cell-permeant second messenger analogue, 8-bromo-3,5-cyclic guanosine monophosphate (8-Br-cGMP), results in a time-dependent increase in the content of oxidised methionine residues. Interestingly, the group of proteins affected by c

Late Onset Cobalamin Disorder and Hemolytic Uremic Syndrome: A Rare Cause of Nephrotic Syndrome

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Gianluigi Ardissino

2017-01-01

Full Text Available Hemolytic uremic syndrome (HUS is an unrare and severe thrombotic microangiopathy (TMA caused by several pathogenetic mechanisms among which Shiga toxin-producing Escherichia coli infections and complement dysregulation are the most common. However, very rarely and particularly in neonates and infants, disorders of cobalamin metabolism (CblC can present with or be complicated by TMA. Herein we describe a case of atypical HUS (aHUS related to CblC disease which first presented in a previously healthy boy at age of 13.6 years. The clinical picture was initially dominated by nephrotic range proteinuria and severe hypertension followed by renal failure. The specific treatment with high dose of hydroxycobalamin rapidly obtained the remission of TMA and the complete recovery of renal function. We conclude that plasma homocysteine and methionine determinations together with urine organic acid analysis should be included in the diagnostic work-up of any patient with TMA and/or nephrotic syndrome regardless of age.

Enzymatic extraction of cobalamin from monoclonal antibody captured haptocorrin and transcobalamin

DEFF Research Database (Denmark)

Hardlei, Tore Forsingdal; Mørkbak, Anne Louise; Nexo, Ebba

2007-01-01

OBJECTIVES: Current extraction methods for cobalamins from serum influence the molecular characteristics of the vitamin. Therefore, an extraction procedure that leaves the cobalamins unchanged is needed. DESIGN AND METHODS: Monoclonal antibodies towards transcobalamin (TC) and haptocorrin (HC) (in...

The marker of cobalamin deficiency, plasma methylmalonic acid, correlates to plasma creatinine

DEFF Research Database (Denmark)

Hvas, A M; Juul, S; Gerdes, Lars Ulrik

2000-01-01

OBJECTIVE: To examine the relationship between the two diagnostic tests, plasma methylmalonic acid and plasma cobalamins, and their association with plasma creatinine, age and sex. DESIGN: Cross-sectional study of simultaneous laboratory measurements. SETTING: County of Aarhus, Denmark. SUBJECTS......: Records on 1689 patients who had their first plasma methylmalonic acid measurement during 1995 and 1996, and who had a simultaneous measurement of plasma cobalamins. Plasma creatinine values measured within a week of measurements of plasma methylmalonic acid and plasma cobalamins were available for 1255...... of the patients. MAIN OUTCOME MEASURES: Predictors of variation in plasma methylmalonic acid; plasma cobalamins, plasma creatinine, age and sex. RESULTS: Plasma methylmalonic acid was positively correlated with plasma creatinine, even for plasma creatinine within the normal range. These associations remained...

Characterization and immunohistochemical localization of rat salivary cobalamin-binding protein and comparison with human salivary haptocorrin

DEFF Research Database (Denmark)

Nexø, Ebba; Poulsen, Steen Seier

1985-01-01

Rat saliva contains a cobalamin-binding protein that binds cobalamin as well as cobinamide. The protein binds cobalamin with an affinity constant of 8 X 10(10) l X mol-1, and it binds cobalamin over a more narrow pH range (pH 7.5-10) than does human haptocorrin. It has a Stokes radius of 2.45 nm...

Guidelines for the diagnosis and management of cystathionine beta-synthase deficiency

NARCIS (Netherlands)

Morris, A.A.; Kozich, V.; Santra, S.; Andria, G.; Ben-Omran, T.I.; Chakrapani, A.B.; Crushell, E.; Henderson, M.J.; Hochuli, M.; Huemer, M.; Janssen, M.C.H.; Maillot, F.; Mayne, P.D.; McNulty, J.; Morrison, T.M.; Ogier, H.; O'Sullivan, S.; Pavlikova, M.; Almeida, I.T. de; Terry, A.; Yap, S.; Blom, H.J.; Chapman, K.A.

2017-01-01

Cystathionine beta-synthase (CBS) deficiency is a rare inherited disorder in the methionine catabolic pathway, in which the impaired synthesis of cystathionine leads to accumulation of homocysteine. Patients can present to many different specialists and diagnosis is often delayed. Severely affected

In Vitro Optimization of Enzymes Involved in Precorrin-2 Synthesis Using Response Surface Methodology.

Science.gov (United States)

Fang, Huan; Dong, Huina; Cai, Tao; Zheng, Ping; Li, Haixing; Zhang, Dawei; Sun, Jibin

2016-01-01

In order to maximize the production of biologically-derived chemicals, kinetic analyses are first necessary for predicting the role of enzyme components and coordinating enzymes in the same reaction system. Precorrin-2 is a key precursor of cobalamin and siroheme synthesis. In this study, we sought to optimize the concentrations of several molecules involved in precorrin-2 synthesis in vitro: porphobilinogen synthase (PBGS), porphobilinogen deaminase (PBGD), uroporphyrinogen III synthase (UROS), and S-adenosyl-l-methionine-dependent urogen III methyltransferase (SUMT). Response surface methodology was applied to develop a kinetic model designed to maximize precorrin-2 productivity. The optimal molar ratios of PBGS, PBGD, UROS, and SUMT were found to be approximately 1:7:7:34, respectively. Maximum precorrin-2 production was achieved at 0.1966 ± 0.0028 μM/min, agreeing with the kinetic model's predicted value of 0.1950 μM/min. The optimal concentrations of the cofactor S-adenosyl-L-methionine (SAM) and substrate 5-aminolevulinic acid (ALA) were also determined to be 200 μM and 5 mM, respectively, in a tandem-enzyme assay. By optimizing the relative concentrations of these enzymes, we were able to minimize the effects of substrate inhibition and feedback inhibition by S-adenosylhomocysteine on SUMT and thereby increase the production of precorrin-2 by approximately five-fold. These results demonstrate the effectiveness of kinetic modeling via response surface methodology for maximizing the production of biologically-derived chemicals.

Influence of duration and dose of metformin on cobalamin deficiency in type 2 diabetes patients using metformin

NARCIS (Netherlands)

Beulens, Joline W J; Hart, Huberta E.; Kuijs, Ron; Kooijman-Buiting, Antoinette M J; Rutten, Guy E H M

2015-01-01

Metformin use is associated with cobalamin (vitamin B12) deficiency. However, the influence of both duration and dose of metformin is unclear. Studies using holotranscobalamin, a marker for cellular cobalamin deficiency, are scarce. We therefore investigated the prevalence of cobalamin deficiency in

Effect of gastric anacidity on the intestinal absorption of liver bound 57Co-labelled cobalamins

International Nuclear Information System (INIS)

Kittang, E.

1987-01-01

57 Co-labelled cyanocobalamin injected in rabbit was transformed within the liver to 57 Co-labelled desoxyadenosylcobalamin and methylcovalamin. The absorption of 57 Co-labelled liver bound cobalamins could be determined with acceptable accuracy by the double isotope fecal excretion method. Treatment with the H 2-receptor antagonist, ranitidine, did not result in decreased absorption of 57 Co-labelled liver bound cobalamins in healthy individuals. R-protein and the R-proteincobalamin complex were determined by the FPLC Mono S chromatography method with a high degree of correlation to the charcoal method in saliva, gastric and duodenal juice, and with a high degree of reproducibility. Omeprazole markedly inhibited the gastric acid and pepsin secretion, but did nor inhibit the IF secretion. Omeprazole treatment resulted in anacidity in 14 of 17 individuals, but did not reduce the absorption of liver bound 57 Co-labelled cobalamins. The intrinsic factor concentration in gastric aspirates measured during the study was unchanged during omeprazole treatment. The release of cobalamins from liver homogenate was markedly inhibited by neutralized gastric juice in vitro, probably due to decreased pepsin mediated proteolysis. In vivo the cobalamin release from liver homogenate was modestly inhibited in the stomach but was unaffected in jejunum during omeprazole treatment. The major part of 57 Co-labelled liver cobalamins bound to R-protein in acid and neutral gastric juice in vitro, and omeprazole induced anacidity, did not influence the cobalamin binding either in gastric or jejunal juice in vivo

Soybean seeds expressing feedback-insensitive cystathionine γ-synthase exhibit a higher content of methionine.

Science.gov (United States)

Song, Shikui; Hou, Wensheng; Godo, Itamar; Wu, Cunxiang; Yu, Yang; Matityahu, Ifat; Hacham, Yael; Sun, Shi; Han, Tianfu; Amir, Rachel

2013-04-01

Soybean seeds provide an excellent source of protein for human and livestock nutrition. However, their nutritional quality is hampered by a low concentration of the essential sulfur amino acid, methionine (Met). In order to study factors that regulate Met synthesis in soybean seeds, this study used the Met-insensitive form of Arabidopsis cystathionine γ-synthase (AtD-CGS), which is the first committed enzyme of Met biosynthesis. This gene was expressed under the control of a seed-specific promoter, legumin B4, and used to transform the soybean cultivar Zigongdongdou (ZD). In three transgenic lines that exhibited the highest expression level of AtD-CGS, the level of soluble Met increased significantly in developing green seeds (3.8-7-fold). These seeds also showed high levels of other amino acids. This phenomenon was more prominent in two transgenic lines, ZD24 and ZD91. The total Met content, which including Met incorporated into proteins, significantly increased in the mature dry seeds of these two transgenic lines by 1.8- and 2.3-fold, respectively. This elevation was accompanied by a higher content of other protein-incorporated amino acids, which led to significantly higher total protein content in the seeds of these two lines. However, in a third transgenic line, ZD01, the level of total Met and the level of other amino acids did not increase significantly in the mature dry seeds. This line also showed no significant change in protein levels. This suggests a positive connection between high Met content and the synthesis of other amino acids that enable the synthesis of more seed proteins.

Levels of Key Enzymes of Methionine-Homocysteine Metabolism in Preeclampsia

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Alejandra Pérez-Sepúlveda

2013-01-01

Full Text Available Objective. To evaluate the role of key enzymes in the methionine-homocysteine metabolism (MHM in the physiopathology of preeclampsia (PE. Methods. Plasma and placenta from pregnant women (32 controls and 16 PE patients were analyzed after informed consent. Protein was quantified by western blot. RNA was obtained with RNA purification kit and was quantified by reverse transcritase followed by real-time PCR (RT-qPCR. Identification of the C677T and A1298C methylenetetrahydrofolate reductase (MTHFR single-nucleotide polymorphisms (SNPs and A2756G methionine synthase (MTR SNP was performed using PCR followed by a high-resolution melting (HRM analysis. S-adenosyl methionine (SAM and S-adenosyl homocysteine (SAH were measured in plasma using high-performance liquid chromatography-tandem mass spectrometry (HPLC/MS/MS. The SNP association analysis was carried out using Fisher’s exact test. Statistical analysis was performed using a Mann-Whitney test. Results. RNA expression of MTHFR and MTR was significantly higher in patients with PE as compared with controls. Protein, SAM, and SAH levels showed no significant difference between preeclamptic patients and controls. No statistical differences between controls and PE patients were observed with the different SNPs studied. Conclusion. The RNA expression of MTHFR and MTR is elevated in placentas of PE patients, highlighting a potential compensation mechanism of the methionine-homocysteine metabolism in the physiopathology of this disease.

Cobalamin deficiency associated with erythroblastic anemia and methylmalonic aciduria in a border collie.

Science.gov (United States)

Morgan, L W; McConnell, J

1999-01-01

Anemia due to cobalamin deficiency is a rare genetic disorder that has been recognized in dogs only recently. This report concerns a 14-month-old border collie that presented for chronic, nonregenerative anemia. Cytological examination of a peripheral blood smear showed the presence of erythroblasts. Serum cobalamin levels were below reference ranges reported for clinically normal dogs. A methylmalonic aciduria was found on urinalysis. These signs are consistent with the anemia in Imerslund-Graesbeck syndrome reported in humans. Anemia due to cobalamin deficiency responds to parenteral vitamin B12 therapy, and affected animals have a good prognosis for recovery.

Nutritional Intake and Status of Cobalamin and Folate among Non-Pregnant Women of Reproductive Age in Bhaktapur, Nepal

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Ram K. Chandyo

2016-06-01

Full Text Available Cobalamin and folate are especially important for women of childbearing age due to their ubiquitous role in fetal growth and development. Population-based data on cobalamin and folate status are lacking from Nepal, where diets are mostly vegetarian. The objectives of the study were to investigate cobalamin and folate intake and status, and to explore associations with socio-demographics, anthropometrics, anemia, and dietary habits. Following a random selection of geographical clusters, we collected blood samples from 500 non-pregnant women and 24-h dietary recalls and food frequency questionnaires from a subsample of 379 women. Twenty percent of the women did not consume any food containing cobalamin during the days recalled, and in 72% nutritional cobalamin intake was <1 μg/day. Eighty-four percent of the women had cobalamin intake lower than the estimated average requirement (EAR (<2 μg/day. In contrast, only 12% of the women had a folate intake less than 100 μg per day, whereas 62% had intake between 100 and 320 μg. Low plasma cobalamin (<150 pmol/L was found in 42% of the women, most of whom (88% also had elevated levels of methylmalonic acid. Our results indicated a high prevalence of nutritional cobalamin deficiency, while folate deficiency was uncommon.

Relationship between cobalamin-dependent metabolites and both serum albumin and alpha1 -proteinase inhibitor concentrations in hypocobalaminemic dogs of 7 different breeds.

Science.gov (United States)

Grützner, Niels; Suchodolski, Jan S; Steiner, Jörg M

2014-12-01

Increased serum concentrations of homocysteine (HCY) and methylmalonic acid (MMA), the 2 main cobalamin-dependent metabolites, as well as decreased serum albumin and canine alpha1 -proteinase inhibitor (cα1 -PI) concentrations have previously been described in hypocobalaminemic dogs with gastrointestinal disease. However, no studies have been conducted to evaluate potential relationships between these serum biomarkers. The aim of this study was to evaluate the relationship between HCY and MMA, 2 cobalamin-dependent metabolites, and both serum albumin and cα1 -PI concentrations in hypocobalaminemic dogs. Serum samples from 285 dogs including 7 different breeds (Beagle, Boxer, Cocker Spaniel, German Shepherd, Labrador Retriever, Chinese Shar-Pei, and Yorkshire Terrier) with hypocobalaminemia were used. Serum HCY, MMA, albumin, and cα1 -PI concentrations were determined. There was a significant correlation between serum HCY and albumin concentrations, as well as serum HCY and cα1 -PI concentrations (ρ = 0.62 and ρ = 0.37, respectively; P  .05). In addition, significant breed-specific correlations were observed between serum MMA and albumin concentrations in German Shepherds, and serum HCY and MMA concentrations in Chinese Shar-Peis with hypocobalaminemia. This study shows a correlation between serum albumin and cα1 -PI and HCY concentrations, but not with serum MMA concentration in dogs with hypocobalaminemia. In addition, significant breed-specific correlations were observed between serum MMA and albumin concentrations in German Shepherds, as well as serum HCY and MMA concentrations in Chinese Shar-Peis, emphasizing the unique metabolic interactions in those dog breeds affected by hypocobalaminemia. © 2014 American Society for Veterinary Clinical Pathology.

Oral versus intramuscular cobalamin treatment in megaloblastic anemia: a single-center, prospective, randomized, open-label study.

Science.gov (United States)

Bolaman, Zahit; Kadikoylu, Gurhan; Yukselen, Vahit; Yavasoglu, Irfan; Barutca, Sabri; Senturk, Taskin

2003-12-01

Cobalamin (vitamin B12) deficiency, the most common cause of megaloblastic anemia, is treated with intramuscular (IM) cobalamin. It has been suggested by some investigators that oral (p.o.) cobalamin treatment may be as effective in the treatment of this condition, with the advantages of ease of administration and lower cost. This study assessed the effects and cost of p.o. versus i.m. cobalamin treatment in patients with megaloblastic anemia due to cobalamin deficiency. This was a 90-day, prospective, randomized, open-label study conducted at the Division of Hematology, Department of Internal Medicine, Adnan Menderes University Research and Practice Hospital (Aydin, Turkey). Patients aged > or =16 years with megaloblastic anemia due to cobalamin deficiency were randomized to receive 1000-microg cobalamin p.o. once daily for 10 days (p.o. group) or 1000-microg cobalamin i.m. once daily for 10 days (i.m. group). After 10 days, both treatments were administered once a week for 4 weeks, and after that, once a month for life. Patients were assessed for the presence of reticulocytosis between treatment days 5 and 10 until it was detected. Therapeutic effectiveness was assessed by measuring hematologic parameters on days 0, 10, 30, and 90 and serum vitamin B12 concentration on days 0 and 90. The Mini-Mental State Examination was used before and after the B12 therapy for cognitive function assessment and 125-Hz diapozone was used for vibration threshold testing. Neurologic sensory assessment, including soft-touch and pinprick examinations, was used to identify neuropathy at baseline and study end. Tolerability was assessed using laboratory tests and patient interview. Cost was assessed using the cost of the study drug and of the injection. Sixty patients completed the study 26 in the p.o. group (16 men, 10 women; mean [SD] age, 60 [15] years) and 34 in the i.m. group (17 men, 17 women; mean [SD] age, 64 [10] years). Reticulocytosis was observed in all patients. In the p

NCBI nr-aa BLAST: CBRC-LAFR-01-1256 [SEVENS

Lifescience Database Archive (English)

Full Text Available CBRC-LAFR-01-1256 ref|ZP_01754413.1| cobalamin 5'-phosphate synthase [Roseobacter s...p. SK209-2-6] gb|EBA16605.1| cobalamin 5'-phosphate synthase [Roseobacter sp. SK209-2-6] ZP_01754413.1 2.2 36% ...

The effects of enhanced methionine synthesis on amino acid and anthocyanin content of potato tubers

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Bánfalvi Zsófia

2008-06-01

Full Text Available Abstract Background Potato is a staple food in the diet of the world's population and also being used as animal feed. Compared to other crops, however, potato tubers are relatively poor in the essential amino acid, methionine. Our aim was to increase the methionine content of tubers by co-expressing a gene involved in methionine synthesis with a gene encoding a methionine-rich storage protein in potato plants. Results In higher plants, cystathionine γ-synthase (CgS is the first enzyme specific to methionine biosynthesis. We attempted to increase the methionine content of tubers by expressing the deleted form of the Arabidopsis CgS (CgSΔ90, which is not regulated by methionine, in potato plants. To increase the incorporation of free methionine into a storage protein the CgSΔ90 was co-transformed with the methionine-rich 15-kD β-zein. Results demonstrated a 2- to 6-fold increase in the free methionine content and in the methionine content of the zein-containing protein fraction of the transgenic tubers. In addition, in line with higher methionine content, the amounts of soluble isoleucine and serine were also increased. However, all of the lines with high level of CgSΔ90 expression were phenotypically abnormal showing severe growth retardation, changes in leaf architecture and 40- to 60% reduction in tuber yield. Furthermore, the colour of the transgenic tubers was altered due to the reduced amounts of anthocyanin pigments. The mRNA levels of phenylalanine ammonia-lyase (PAL, the enzyme catalysing the first step of anthocyanin synthesis, were decreased. Conclusion Ectopic expression of CgSΔ90 increases the methionine content of tubers, however, results in phenotypic aberrations in potato. Co-expression of the 15-kD β-zein with CgSΔ90 results in elevation of protein-bound methionine content of tubers, but can not overcome the phenotypical changes caused by CgSΔ90 and can not significantly improve the nutritional value of tubers. The level

Efficacy of DL-methionine hydroxy analogue-free acid in comparison to DL-methionine in growing male white Pekin ducks.

Science.gov (United States)

Kluge, H; Gessner, D K; Herzog, E; Eder, K

2016-03-01

The present study was performed to assess the bioefficacy of DL-methionine hydroxy analogue-free acid (MHA) in comparison to DL-methionine (DLM) as sources of methionine for growing male white Pekin ducks in the first 3 wk of life. For this aim, 580 1-day-old male ducks were allocated into 12 treatment groups and received a basal diet that contained 0.29% of methionine, 0.34% of cysteine and 0.63% of total sulphur containing amino acids or the same diet supplemented with either DLM or MHA in amounts to supply 0.05, 0.10, 0.15, 0.20, and 0.25% of methionine equivalents. Ducks fed the control diet without methionine supplement had the lowest final body weights, daily body weight gains and feed intake among all groups. Supplementation of methionine improved final body weights and daily body weight gains in a dose dependent-manner. There was, however, no significant effect of the source of methionine on all of the performance responses. Evaluation of the data of daily body weight gains with an exponential model of regression revealed a nearly identical efficacy (slope of the curves) of both compounds for growth (DLM = 100%, MHA = 101%). According to the exponential model of regression, 95% of the maximum values of daily body weight gain were reached at methionine supplementary levels of 0.080% and 0.079% for DLM and MHA, respectively. Overall, the present study indicates that MHA and DLM have a similar efficacy as sources of methionine for growing ducks. It is moreover shown that dietary methionine concentrations of 0.37% are required to reach 95% of the maximum of daily body weight gains in ducks during the first 3 wk of life. © 2015 Poultry Science Association Inc.

Cobalamin and folate status predicts mental development scores in North Indian children 12-18 mo of age.

Science.gov (United States)

Strand, Tor A; Taneja, Sunita; Ueland, Per M; Refsum, Helga; Bahl, Rajiv; Schneede, Joern; Sommerfelt, Halvor; Bhandari, Nita

2013-02-01

Micronutrient deficiencies can affect cognitive function. Many young children in low- and middle-income countries have inadequate cobalamin (vitamin B-12) status. The objective was to measure the association of plasma concentrations of folate, cobalamin, total homocysteine, and methylmalonic acid with cognitive performance at 2 occasions, 4 mo apart, in North Indian children aged 12-18 mo. Bayley Scales of Infant Development II were used to assess cognition. In multiple regression models adjusted for several potential confounders, we measured the association between biomarkers for folate and cobalamin status and psychomotor or mental development scores on the day of blood sampling and 4 mo thereafter. Each 2-fold increment in plasma cobalamin concentration was associated with a significant increment in the mental development index score of 1.3 (95% CI: 0.2, 2.4; P = 0.021). Furthermore, each 2-fold increment in homocysteine or methylmalonic acid concentration was associated with a decrement in mental development index score of 2.0 (95% CI: 0.5, 3.4; P = 0.007) or 1.1 (95% CI: 0.3, 1.8; P = 0.004) points, respectively. Plasma folate concentration was significantly and independently associated with mental development index scores only when children with poor cobalamin status were excluded, ie, in those who had cobalamin concentrations below the 25th percentile. None of these markers was associated with psychomotor scores in the multiple regression models. Cobalamin and folate status showed a statistically significant association with cognitive performance. Given the high prevalence of deficiencies in these nutrients, folate and cobalamin supplementation trials are required to measure any beneficial effect on cognition.

CONCENTRATION-DEPENDENT LINKAGE OF DIETARY METHIONINE RESTRICTION TO THE COMPONENTS OF ITS METABOLIC PHENOTYPE

OpenAIRE

Forney, Laura A.; Wanders, Desiree; Stone, Kirsten P.; Pierse, Alicia; Gettys, Thomas W.

2017-01-01

Objective Restricting dietary methionine to 0.17% produces a series of physiological responses through coordinated transcriptional effects in liver and adipose tissue. The goal of the present work was to determine the threshold concentrations above and below 0.17% at which the beneficial responses to 0.17% dietary methionine are preserved. Methods Diets were formulated to restrict methionine to different degrees, followed by evaluation of the transcriptional and physiological responses to the...

Crystallization of the novel S-adenosyl-l-methionine-dependent C-methyltransferase CouO from Streptomyces rishiriensis and preliminary diffraction data analysis

International Nuclear Information System (INIS)

Lyskowski, Andrzej; Tengg, Martin; Steinkellner, Georg; Schwab, Helmut; Gruber-Khadjawi, Mandana; Gruber, Karl

2012-01-01

Recombinant Q9F8T9 protein from Streptomyces rishiriensis (CouO), an S-adenosyl-l-methionine-dependent C-methyltransferase, has been successfully cloned, expressed and purified. Recombinant Q9F8T9 protein from Streptomyces rishiriensis (CouO), an S-adenosyl-l-methionine-dependent C-methyltransferase, has been successfully cloned, expressed and purified. CouO was crystallized from a single condition in the Morpheus crystallization screen. A vitrified crystal diffracted to 2.05 Å resolution and belonged to space group P2 1 , with unit-cell parameters a = 33.02, b = 82.87, c = 76.77 Å, β = 96.93°

An Amoebal Grazer of Cyanobacteria Requires Cobalamin Produced by Heterotrophic Bacteria.

Science.gov (United States)

Ma, Amy T; Beld, Joris; Brahamsha, Bianca

2017-05-15

Amoebae are unicellular eukaryotes that consume microbial prey through phagocytosis, playing a role in shaping microbial food webs. Many amoebal species can be cultivated axenically in rich media or monoxenically with a single bacterial prey species. Here, we characterize heterolobosean amoeba LPG3, a recent natural isolate, which is unable to grow on unicellular cyanobacteria, its primary food source, in the absence of a heterotrophic bacterium, a Pseudomonas species coisolate. To investigate the molecular basis of this requirement for heterotrophic bacteria, we performed a screen using the defined nonredundant transposon library of Vibrio cholerae , which implicated genes in corrinoid uptake and biosynthesis. Furthermore, cobalamin synthase deletion mutations in V. cholerae and the Pseudomonas species coisolate do not support the growth of amoeba LPG3 on cyanobacteria. While cyanobacteria are robust producers of a corrinoid variant called pseudocobalamin, this variant does not support the growth of amoeba LPG3. Instead, we show that it requires cobalamin that is produced by the Pseudomonas species coisolate. The diversity of eukaryotes utilizing corrinoids is poorly understood, and this amoebal corrinoid auxotroph serves as a model for examining predator-prey interactions and micronutrient transfer in bacterivores underpinning microbial food webs. IMPORTANCE Cyanobacteria are important primary producers in aquatic environments, where they are grazed upon by a variety of phagotrophic protists and, hence, have an impact on nutrient flux at the base of microbial food webs. Here, we characterize amoebal isolate LPG3, which consumes cyanobacteria as its primary food source but also requires heterotrophic bacteria as a source of corrinoid vitamins. Amoeba LPG3 specifically requires the corrinoid variant produced by heterotrophic bacteria and cannot grow on cyanobacteria alone, as they produce a different corrinoid variant. This same corrinoid specificity is also

Cobalamin Protection against Oxidative Stress in the Acidophilic Iron-oxidizing Bacterium Leptospirillum group II CF-1

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Gloria Paz Levicán

2016-05-01

Full Text Available Members of the genus Leptospirillum are aerobic iron-oxidizing bacteria belonging to the phylum Nitrospira. They are important members of microbial communities that catalyze the biomining of sulfidic ores, thereby solubilizing metal ions. These microorganisms live under extremely acidic and metal-loaded environments and thus must tolerate high concentrations of reactive oxygen species. Cobalamin (vitamin B12 is a cobalt-containing tetrapyrrole cofactor involved in intramolecular rearrangement reactions and has recently been suggested to be an intracellular antioxidant. In this work, we investigated the effect of the exogenous addition of cobalamin on oxidative stress parameters in Leptospirillum group II strain CF-1. Our results revealed that the external supplementation of cobalamin reduces the levels of intracellular reactive oxygen species and the damage to biomolecules, and also stimulates the growth and survival of cells exposed to oxidative stress exerted by ferric ion, hydrogen peroxide, chromate and diamide. Furthermore, exposure of strain CF-1 to oxidative stress elicitors resulted in the transcriptional activation of the cbiA gene encoding CbiA of the cobalamin biosynthetic pathway. Altogether, these data suggest that cobalamin plays an important role in redox protection of Leptospirillum strain CF-1, supporting survival of this microorganism under extremely oxidative environmental conditions. Understanding the mechanisms underlying the protective effect of cobalamin against oxidative stress may help to develop strategies to make biomining processes more effective.

S-Adenosylmethionine and S-adenosylhomocystein metabolism in isolated rat liver. Effects of L-methionine, L-homocystein, and adenosine.

Science.gov (United States)

Hoffman, D R; Marion, D W; Cornatzer, W E; Duerre, J A

1980-11-25

The effects of varying concentrations of L-methionine, L-homocysteine, and adenosine on the tissue levels of S-adenosylmethionine (AdoMet) and S-adenosyl-homocystein (AdoHcy) were investigated in perfused liver. In the normal liver, the intracellular concentration of AdoMet was dependent upon the availability of methionine. In the presence of high concentrations of methionine the maximum level of AdoMet attainable was 300 nmol/g of liver. The exogenous concentration of methionine did not alter the hepatic concentration of AdoHcy (8 to 20 nmol/g) while adenosine or homocysteine blocked hydrolysis of AdoHcy resulting in elevated levels of AdoHcy (400 to 600 nmol/g) and AdoMet (300 to 600 nmol/g). The addition of both adenosine (4mM) and homocysteine (3.4 mM) to the perfusate further increased the levels of AdoHcy (4 mumol/g) and AdoMet (1.2 mumol/g). As the concentration of AdoHcy increased, significant amounts of this compound were released into the perfusate, while AdoMet was not detected. Under all conditions where AdoHcy accumulated in the cell, a concomitant increase in the AdoMet level occurred. Apparently AdoHcy acts as a positive effector of the S-adenosylmethionine synthase. The hepatocytes did not take up significant amounts of [methyl-14C]AdoMet from the perfusate nor were any [14C]methyl groups from this compound incorporated into histones, DNA, or phospholipids. In contrast, [14C]methyl groups were readily incorporated into these macromolecules from exogenous [methyl-14C]methionine. The addition of adenosine (4 mM) and homocystein (3.4 mM) shifted the AdoMet:AdoHcy ratio from 8.2 to 0.3. Under these conditions, transmethylation was inhibited markedly.

Genetic disorders of vitamin B12 metabolism: eight complementation groups – eight genes

Science.gov (United States)

Froese, D. Sean; Gravel, Roy A.

2010-01-01

Vitamin B12 (cobalamin, Cbl) is an essential nutrient in human metabolism. Genetic diseases of vitamin B12 utilisation constitute an important fraction of inherited newborn disease. Functionally, B12 is the cofactor for methionine synthase and methylmalonyl CoA mutase. To function as a cofactor, B12 must be metabolised through a complex pathway that modifies its structure and takes it through subcellular compartments of the cell. Through the study of inherited disorders of vitamin B12 utilisation, the genes for eight complementation groups have been identified, leading to the determination of the general structure of vitamin B12 processing and providing methods for carrier testing, prenatal diagnosis and approaches to treatment. PMID:21114891

Determination of vitamin B12 (cobalamine) absorption by means of a simple double-isotope technique

International Nuclear Information System (INIS)

Hippe, E.; Brynskov, J.; Gimsing, P.; Hjelt, K.

1986-01-01

The background, practical instruction and clinical results of a simplified method of determining the absorption of cobalamine (vitamin B 12 ) are presented. The simultaneous administration of 57 CO-CN-cobalamine, a non-absorbable marker ( 51 CrCl 3 ), and red carmine tablets enable quantitative assessments of the cobalamine absorption by collection of a small red feaces sample. In contrast to the classical Schilling-test, this vitamin B 12 absorption test (B 12 -ABS-test) or faeces-spot-test is, independent of fasting, flushing dose, renal function and diurnal urinary collection. This is documented in a series of clinical studies. The B 12 -ABS-test provides accurate and precise results compared to the reference method (whole-body-counting). The Schilling test, on the contrary, gives approximately 50% false low values in a reference group of elderly hospitalized patients. A modification of the B 12 -ABS-test, has been used to determine the cobalamine absorption in children, and a set of age-related reference intervals have been established, together with quantitative measurements of the cobalamine absorption in children with small bowel diseases. Based on several years of practical experience, we recommend replacement of the Schilling test by this simple double-isotope technique. (author)

Diagnosis and management of clinical and subclinical cobalamin deficiencies: why controversies persist in the age of sensitive metabolic testing.

Science.gov (United States)

Carmel, Ralph

2013-05-01

In the past two decades, sensitive biochemical tests have uncovered cobalamin deficiency much more frequently than ever before. Almost all cases involve mild, biochemical changes without clinical manifestations (subclinical cobalamin deficiency; SCCD), whose health impact is unclear. Because the causes of SCCD are most often unknown, nonmalabsorptive, and seldom documented, controversy and confusion surround the diagnostic criteria and, inevitably, consequences and management of SCCD. To complicate matters, our grasp of the rarer clinical deficiency, usually a serious, progressive medical disease rooted in severe malabsorption, has receded as absorption testing has disappeared. Reexamining the accumulation of assumptions and misperceptions about cobalamin deficiency and distinguishing SCCD from clinical deficiency is long overdue. The biology of cobalamin provides an important starting point: cobalamin stores exceed daily losses so greatly and binding proteins regulate absorption so effectively that deficiency typically achieves clinical expression only after years of severe, relentless malabsorption. Dietary insufficiency, mild, partial malabsorption, and other incomplete, intermittent causes can usually produce only SCCD. Thus, the most fundamental difference between the two deficiencies is the relentlessness of the underlying cause, which determines prognosis and health impact. Inattention to absorptive status has exacerbated the limitations of biochemical testing. All the biochemical tests are highly sensitive but specificity is poor, no diagnostic gold standard exists, and diagnostic cutpoints fluctuate excessively. To limit the adverse diagnostic consequences, the diagnosis of SCCD, whose need for treatment is unclear, should be deferred unless at least two tests are abnormal. Indeed, cobalamin biology indicates that the absorption system, while enhancing cobalamin delivery, also sets a strict upper limit on it, which suggests that cobalamin excess is

Development of CHARMM-Compatible Force-Field Parameters for Cobalamin and Related Cofactors from Quantum Mechanical Calculations.

Science.gov (United States)

Pavlova, Anna; Parks, Jerry M; Gumbart, James C

2018-02-13

Corrinoid cofactors such as cobalamin are used by many enzymes and are essential for most living organisms. Therefore, there is broad interest in investigating cobalamin-protein interactions with molecular dynamics simulations. Previously developed parameters for cobalamins are based mainly on crystal structure data. Here, we report CHARMM-compatible force field parameters for several corrinoids developed from quantum mechanical calculations. We provide parameters for corrinoids in three oxidation states, Co 3+ , Co 2+ , and Co 1+ , and with various axial ligands. Lennard-Jones parameters for the cobalt center in the Co(II) and Co(I) states were optimized using a helium atom probe, and partial atomic charges were obtained with a combination of natural population analysis (NPA) and restrained electrostatic potential (RESP) fitting approaches. The Force Field Toolkit was used to optimize all bonded terms. The resulting parameters, determined solely from calculations of cobalamin alone or in water, were then validated by assessing their agreement with density functional theory geometries and by analyzing molecular dynamics simulation trajectories of several corrinoid proteins for which X-ray crystal structures are available. In each case, we obtained excellent agreement with the reference data. In comparison to previous CHARMM-compatible parameters for cobalamin, we observe a better agreement for the fold angle and lower RMSD in the cobalamin binding site. The approach described here is readily adaptable for developing CHARMM-compatible force-field parameters for other corrinoids or large biomolecules.

Vitamin-responsive disorders: cobalamin, folate, biotin, vitamins B1 and E.

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Baumgartner, Matthias R

2013-01-01

The catalytic properties of many enzymes depend on the participation of vitamins as obligatory cofactors. Vitamin B12 (cobalamin) and folic acid (folate) deficiencies in infants and children classically present with megaloblastic anemia and are often accompanied by neurological signs. A number of rare inborn errors of cobalamin and folate absorption, transport, cellular uptake, and intracellular metabolism have been delineated and identification of disease-causing mutations has improved our ability to diagnose and treat many of these conditions. Two inherited defects in biotin metabolism are known, holocarboxylase synthetase and biotinidase deficiency. Both lead to multiple carboxylase deficiency manifesting with metabolic acidosis, neurological abnormalities, and skin rash. Thiamine-responsive megaloblastic anemia is characterized by megaloblastic anemia, non-type I diabetes, and sensorineural deafness that responds to pharmacological doses of thiamine (vitamin B1). Individuals affected with inherited vitamin E deficiencies including ataxia with isolated vitamin E deficiency and abetalipoproteinemia present with a spinocerebellar syndrome similar to patients with Friedreich's ataxia. If started early, treatment of these defects by oral or parenteral administration of the relevant vitamin often results in correction of the metabolic defect and reversal of the signs of disease, stressing the importance of early and correct diagnosis in these treatable conditions. Copyright © 2013 Elsevier B.V. All rights reserved.

Transgenic tobacco plants having a higher level of methionine are more sensitive to oxidative stress.

Science.gov (United States)

Hacham, Yael; Matityahu, Ifat; Amir, Rachel

2017-07-01

Methionine is an essential amino acid the low level of which limits the nutritional quality of plants. We formerly produced transgenic tobacco (Nicotiana tabacum) plants overexpressing CYSTATHIONE γ-SYNTHASE (CGS) (FA plants), methionine's main regulatory enzyme. These plants accumulate significantly higher levels of methionine compared with wild-type (WT) plants. The aim of this study was to gain more knowledge about the effect of higher methionine content on the metabolic profile of vegetative tissue and on the morphological and physiological phenotypes. FA plants exhibit slightly reduced growth, and metabolic profiling analysis shows that they have higher contents of stress-related metabolites. Despite this, FA plants were more sensitive to short- and long-term oxidative stresses. In addition, compared with WT plants and transgenic plants expressing an empty vector, the primary metabolic profile of FA was altered less during oxidative stress. Based on morphological and metabolic phenotypes, we strongly proposed that FA plants having higher levels of methionine suffer from stress under non-stress conditions. This might be one of the reasons for their lesser ability to cope with oxidative stress when it appeared. The observation that their metabolic profiling is much less responsive to stress compared with control plants indicates that the delta changes in metabolite contents between non-stress and stress conditions is important for enabling the plants to cope with stress conditions. © 2017 Scandinavian Plant Physiology Society.

Cobalamin C deficiency in an adolescent with altered mental status and anorexia.

Science.gov (United States)

Rahmandar, Maria H; Bawcom, Amanda; Romano, Mary E; Hamid, Rizwan

2014-12-01

Although cobalamin (cbl) C deficiency is the most common inherited disorder of vitamin B12 metabolism, the late-onset form of the disease can be difficult to recognize because it has a broad phenotypic spectrum. In this report, we describe an adolescent female exposed to unknown illicit substances and sexual abuse who presented with psychosis, anorexia, seizures, and ataxia. The patient's diagnosis was delayed until a metabolic workup was initiated, revealing hyperhomocysteinemia, low normal plasma methionine, and methylmalonic aciduria. Ultimately, cblC deficiency was confirmed when molecular testing showed compound heterozygosity for mutations (c.271dupA and c.482G>A) in the MMACHC gene. This diagnosis led to appropriate treatment with hydroxocobalamin, betaine, and folate, which resulted in improvement of her clinical symptoms and laboratory values. This patient demonstrates a previously unrecognized presentation of late-onset cblC deficiency. Although neuropsychiatric symptoms are common in late-onset disease, seizures and cerebellar involvement are not. Furthermore, anorexia has not been previously described in these patients. This case emphasizes that inborn errors of metabolism should be part of the differential diagnosis for a teenager presenting with altered mental status, especially when the diagnosis is challenging or neurologic symptoms are unexplained. Correct diagnosis of this condition is important because treatment is available and can result in clinical improvement.(1.) Copyright © 2014 by the American Academy of Pediatrics.

EFSA NDA Panel (EFSA Panel on Dietetic Products, Nutrition and Allergies), 2015. Scientific Opinion on Dietary Reference Values for cobalamin (vitamin B12)

DEFF Research Database (Denmark)

Tetens, Inge

2015-01-01

Following a request from the European Commission, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) derived Dietary Reference Values (DRVs) for cobalamin (vitamin B12). The Panel considers that the approach based on a combination of biomarkers of cobalamin status, i.e. serum....... For pregnancy and lactation, additional cobalamin intakes related to the accumulation of cobalamin in fetal tissues and transfer of cobalamin into breast milk are considered and AIs of 4.5 and 5 μg/day, respectively, are proposed....

The subcellular localization of yeast glycogen synthase is dependent upon glycogen content

OpenAIRE

Wilson, Wayne A.; Boyer, Michael P.; Davis, Keri D.; Burke, Michael; Roach, Peter J.

2010-01-01

The budding yeast, Saccharomyces cerevisiae, accumulates the storage polysaccharide glycogen in response to nutrient limitation. Glycogen synthase, the major form of which is encoded by the GSY2 gene, catalyzes the key regulated step in glycogen storage. Here, we utilize Gsy2p fusions to green fluorescent protein (GFP) to determine where glycogen synthase is located within cells. We demonstrate that the localization pattern of Gsy2-GFP depends upon the glycogen content of the cell. When glyco...

Cobalamin Deficiency Results in Increased Production of Formate Secondary to Decreased Mitochondrial Oxidation of One-Carbon Units in Rats.

Science.gov (United States)

MacMillan, Luke; Tingley, Garrett; Young, Sara K; Clow, Kathy A; Randell, Edward W; Brosnan, Margaret E; Brosnan, John T

2018-03-01

Formate is produced in mitochondria via the catabolism of serine, glycine, dimethylglycine, and sarcosine. Formate produced by mitochondria may be incorporated into the cytosolic folate pool where it can be used for important biosynthetic reactions. Previous studies from our lab have shown that cobalamin deficiency results in increased plasma formate concentrations. Our goal was to determine the basis for elevated formate in vitamin B-12 deficiency. Male Sprague Dawley rats were randomly assigned to consume either a cobalamin-replete (50 μg cobalamin/kg diet) or -deficient (no added cobalamin) diet for 6 wk. Formate production was measured in vivo and in isolated liver mitochondria from a variety of one-carbon precursors. We also measured the oxidation of [3-14C]-l-serine to 14CO2 in isolated rat liver mitochondria and the expression of hepatic genes involved in one-carbon unit and formate metabolism. Cobalamin-deficient rats produce formate at a rate 55% higher than that of replete rats. Formate production from serine was increased by 60% and from dimethylglycine and sarcosine by ∼200% in liver mitochondria isolated from cobalamin-deficient rats compared with cobalamin-replete rats. There was a 26% decrease in the 14CO2 produced by mitochondria from cobalamin-deficient rats. Gene expression analysis showed that 10-formyltetrahydrofolate dehydrogenase-cytosolic (Aldh1l1) and mitochondrial (Aldh1l2) expression were decreased by 40% and 60%, respectively, compared to control, while 10-formyltetrahydrofolate synthetase, mitochondrial, monofunctional (Mthfd1l) expression was unchanged. We propose that a bifurcation in mitochondrial one-carbon metabolism is a key control mechanism in determining the fate of one-carbon units, to formate or CO2. During cobalamin deficiency in rats the disposition of 10-formyl-tetrahydrofolate carbon is shifted in favor of formate production. This may represent a mechanism to generate more one-carbon units for the replenishment of the S

Cobalamin status during normal pregnancy and postpartum: a longitudinal study comprising 406 danish women

DEFF Research Database (Denmark)

Milman, N; Byg, KE; Bergholt, T

2006-01-01

-) cobalamin, P-methylmalonic acid and P-homocysteine was measured at 18, 32 and 39 wk gestation and 8 wk postpartum during lactation. RESULTS: P-cobalamin showed a gradual, significant decline during pregnancy (P ... and 8 wk postpartum median values were 225, 172, 161 and 319 pmol/L, respectively. P-methylmalonic displayed a gradual, significant increase during pregnancy as well as postpartum (P homocysteine demonstrated...

Homocysteine, Cobalamin and Folate Status and their Relations to Neurocognitive and Psychological Markers in Elderly in Northeastern of Iran

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Lida Manavifar

2013-06-01

Full Text Available       Objective(s: Incidence of neurocognitive and psychological disorders may be related to serum homocystein (Hcy, cobalamin (vitamin B12 and folate levels in old people. The aim of this study was to assess the relation between Hcy, cobalamin, folate and neurocognitive and/or psychological disorders in the elderly.   Materials and Methods: In this cross-sectional study, 280 subjects with ≥ 65 years old, were evaluated. The subjects were selected from 12 regions of Mashhad, Iran, over March to October 2009. After blood sampling, data were collected by questionnaire, face to face interview and performing neurocognitive and psychological tests. The sera of 250 persons were analyzed for cobalamin and folate by RIA method. Amongst the aforementioned samples, 78 cases with cobalamin Results: Amongst the people, 126 (45% were male and 154 (55% were female. The prevalence of hyperhomocysteinemia (HHcy was 59.5% and 37.1% in male and female respectively (P -value =0.049. Hcy inversely correlated to cobalamin (r=-0.282, P=0.014 and to folate (r=-0.203, P=0.014. Hcy, cobalamin and folate correlations to neurocognitive and psychological impairments were not statically significant. Conclusion: Hyper Hcy or low cobalamin and folate in the elderly, are prevalent but their relationships with neurocognitive and psychological impairments is controversial. If these relationships had been confirmed, performing a single serum Hcy or cobalamin test would have been enough to diagnose and prevent neurocognitive impairments and inversely, neurocognitive-psychological sign and symptoms could have meant probable tissue vitamin deficiencies. However methods of assessing neurocognitive and psychological markers with validity and reliability of clinical and laboratory tests for finding aforementioned relationships should be revised.  

Homocysteine, Cobalamin and Folate Status and their Relations to Neurocognitive and Psychological Markers in Elderly in Northeasten of Iran.

Science.gov (United States)

Manavifar, Lida; Nemati Karimooy, Habibollah; Jamali, Jamshid; Talebi Doluee, Morteza; Shirdel, Abbas; Nejat Shokohi, Amireh; Fatemi Nayyeri, Mahdie

2013-06-01

Incidence of neurocognitive and psychological disorders may be related to serum homocystein (Hcy), cobalamin (vitamin B12) and folate levels in old people. The aim of this study was to assess the relation between Hcy, cobalamin, folate and neurocognitive and/or psychological disorders in the elderly. In this cross-sectional study, 280 subjects with ≥ 65 years old ,were evaluated. The subjects were selected from 12 regions of Mashhad, Iran, over March to October 2009. After blood sampling, data were collected by questionnaire, face to face interview and performing neurocognitive and psychological tests. The sera of 250 persons were analyzed for cobalamin and folate by RIA method. Amongst the aforementioned samples, 78 cases with cobalamin <300 pg/ml and folate <6.5 ng/ml were analyzed for Hcy by ELISA method. Amongst the people, 126 (45%) were male and 154 (55%) were female. The prevalence of hyperhomocysteinemia (HHcy) was 59.5% and 37.1% in male and female respectively (P -value =0.049). Hcy inversely correlated to cobalamin (r=-0.282, P=0.014) and to folate (r=-0.203, P=0.014). Hcy, cobalamin and folate correlations to neurocognitive and psychological impairments were not statically significant. Hyper Hcy or low cobalamin and folate in the elderly, are prevalent but their relationships with neurocognitive and psychological impairments is controversial. If these relationships had been confirmed, performing a single serum Hcy or cobalamin test would have been enough enough to diagnose and prevent neurocognitive impairments and inversely, neurocognitive-psychological sign and symptoms could have meant probable tissue vitamin deficiencies. However methods of assessing neurocognitive and psychological markers with validity and reliability of clinical and laboratory tests for finding aforementioned relationships should be revised.

METHYLMALONIC ACID AND HOMOCYSTEIN SERUM IN DIAGNOSING MEGALOBLASTIC ANEMIA DUE TO COBALAMIN AND FOLATE DEFICIENCY IN TRAVEL MEDICINE

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Made Gian Indra Rahayuda

2014-01-01

Full Text Available Normal 0 false false false EN-US X-NONE X-NONE Anemia is a major global health problem, especially in developing countries. Anemia is a condition where the red blood cell mass and / or hemoglobin mass that circulating in the body was decreased to below normal level so it can not function well in providing oxygen to the body tissues. One of the most common type is megaloblastic anemia. Megaloblastic anemia is mostly caused by vitamin B12 (cobalamin and folate deficiency. One of the causes of cobalamin and folate deficiency anemia is tropical sprue. Cobalamin deficiency anemia and folate deficiency anemia gives a similar symptom, but in cobalamin deficiency there is neuropathy symptoms. Normal serum folate is between 3-15 ng/mL. Normal folate erythrocyte is 150-600 ng/mL. In cobalamin deficiency, serum cobalamin decreased below the cut off point 100pg/mL (normally 100 - 400pg/mL. Other examination such as elevated homocysteine??, methylmalonic acid, or formioglutamic acid (FIGLU in the urine can confirm the diagnosis of cobalamin and folic acid deficiency. There is no consensus on the cut-off point of homocysteine ??and MMA. Homocysteine ??has been considered to increase when the levels are above 12-14 ?mol /L in women and in the 14-15 ?mol/L. According to research by Robert et al in the case of cobalamin deficiency, serum tHcy> 15.0 ?mol/L. Most research considers the increase of MMA in cobalamin deficiency is> 0:28 ?mol / L, but the cut off point in circulation varies between 0:21 to 0:48 ?mol/L. MMA level is increased in serum and urine in cobalamin deficiency, whereas MMA normal in folate deficiency. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font

Successful intrauterine treatment of a patient with cobalamin C defect

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Friedrich K. Trefz

2016-03-01

Full Text Available Cobalamin C (cblC defect is an inherited autosomal recessive disorder that affects cobalamin metabolism. Patients are treated with hydroxycobalamin to ameliorate the clinical features of early-onset disease and prevent clinical symptoms in late-onset disease. Here we describe a patient in whom prenatal maternal treatment with 30 mg/week hydroxycobalamin and 5 mg/day folic acid from week 15 of pregnancy prevented disease manifestation in a girl who is now 11 years old with normal IQ and only mild ophthalmic findings. The affected older sister received postnatal treatment only and is severely intellectually disabled with severe ophthalmic symptoms. This case highlights the potential of early, high-dose intrauterine treatment in a fetus affected by the cblC defect.

Aspirin inhibits interleukin 1-induced prostaglandin H synthase expression in cultured endothelial cells

International Nuclear Information System (INIS)

Wu, K.K.; Sanduja, R.; Tsai, A.L.; Ferhanoglu, B.; Loose-Mitchell, D.S.

1991-01-01

Prostaglandin H (PGH) synthase is a key enzyme in the biosynthesis of prostaglandins, thromboxane, and prostacyclin. In cultured human umbilical vein endothelial cells, interleukin 1 (IL-1) is known to induce the synthesis of this enzyme, thereby raising the level of PGH synthase protein severalfold over the basal level. Pretreatment with aspirin at low concentrations inhibited more than 60% of the enzyme mass and also the cyclooxygenase activity in IL-1-induced cells with only minimal effects on the basal level of the synthase enzyme in cells without IL-1. Sodium salicylate exhibited a similar inhibitory action whereas indomethacin had no apparent effect. Similarly low levels of aspirin inhibited the increased L-[ 35 S]methionine incorporation into PGH synthase that was induced by IL0-1 and also suppressed expression of the 2.7-kilobase PGH synthase mRNA. These results suggest that in cultured endothelial cells a potent inhibition of eicosanoid biosynthetic capacity can be effected by aspirin or salicylate at the level of PGH synthase gene expression. The aspirin effect may well be due to degradation of salicylate

Systemic Scedosporium prolificans infection in an 11-month-old Border collie with cobalamin deficiency secondary to selective cobalamin malabsorption (canine Imerslund-Gräsbeck syndrome).

Science.gov (United States)

Erles, K; Mugford, A; Barfield, D; Leeb, T; Kook, P H

2018-04-01

An 11-month-old Border collie presented collapsed and continued to deteriorate rapidly despite supportive treatment. The dog had a history of failure to thrive and recurring respiratory infection. Laboratory abnormalities included neutrophilic leucocytosis, Heinz body anaemia, hyperammonaemia, hyperbilirubinaemia, proteinuria and hypocobalaminaemia. Post-mortem examination revealed multi-focal necrosis within the heart, kidneys, pancreas, liver, meninges and cerebral cortex. Fungal hyphae in lesions were identified as Scedosporium prolificans following culture. Subsequent genotyping confirmed that the dog carried the CUBN:c.8392delC mutation in a homozygous state, verifying hereditary cobalamin deficiency (a.k.a. Imerslund-Gräsbeck syndrome). Cobalamin deficiency may have been a predisposing factor for the development of systemic fungal infection in this dog. © 2017 British Small Animal Veterinary Association.

Lean Body Mass Harbors Sensing Mechanisms that Allow Safeguarding of Methionine Homeostasis.

Science.gov (United States)

Ingenbleek, Yves

2017-09-20

Protein-depleted states generate allosteric inhibition of liver cystathionine β-synthase (CBS), which governs the first enzymatic step of the transsulfuration cascade, resulting in upstream accretion of homocysteine (Hcy) in body fluids. A similar Hcy increase may arise from normal hepatocytes undergoing experimentally-induced impairment of betaine-homocysteine methyltransferase (BHTM) activity or from components of lean body mass (LBM) submitted to any inflammatory disorder. LBM comprises a composite agglomeration of extrarenal tissues characterized by naturally occurring BHTM inactivity. As a result of cellular injury, LBM releases high concentrations of Hcy into the extracellular space, contrasting with the disruption of normal remethylation pathways. Hyperhomocysteinemia acts as a biomarker, reflecting the severity of insult and operating as an alarm signal. Elevated Hcy levels constitute a precursor pool recognized by a CBS coding region that reacts to meet increased methionine requirements in LBM tissues, using its enhanced production in hepatocytes. Preservation of methionine homeostasis benefits from its high metabolic priority and survival value.

Lean Body Mass Harbors Sensing Mechanisms that Allow Safeguarding of Methionine Homeostasis

Directory of Open Access Journals (Sweden)

Yves Ingenbleek

2017-09-01

Full Text Available Protein-depleted states generate allosteric inhibition of liver cystathionine β-synthase (CBS, which governs the first enzymatic step of the transsulfuration cascade, resulting in upstream accretion of homocysteine (Hcy in body fluids. A similar Hcy increase may arise from normal hepatocytes undergoing experimentally-induced impairment of betaine-homocysteine methyltransferase (BHTM activity or from components of lean body mass (LBM submitted to any inflammatory disorder. LBM comprises a composite agglomeration of extrarenal tissues characterized by naturally occurring BHTM inactivity. As a result of cellular injury, LBM releases high concentrations of Hcy into the extracellular space, contrasting with the disruption of normal remethylation pathways. Hyperhomocysteinemia acts as a biomarker, reflecting the severity of insult and operating as an alarm signal. Elevated Hcy levels constitute a precursor pool recognized by a CBS coding region that reacts to meet increased methionine requirements in LBM tissues, using its enhanced production in hepatocytes. Preservation of methionine homeostasis benefits from its high metabolic priority and survival value.

Effect of cysteine dosage on erythrocyte glutathione synthesis rate in a patient with cystathionine beta synthase deficiency

NARCIS (Netherlands)

van der Crabben, S. N.; Wijburg, F. A.; Ackermans, M. T.; Sauerwein, H. P.

2008-01-01

Cystathionine β-synthase (CBS)-deficient patients develop premature arteriosclerosis and thrombosis leading to a high risk of a vascular event before the age of 30 years. In CBS deficiency the transsulfuration pathway is impaired, leading to markedly elevated levels of homocysteine and methionine,

Homocystinuria due to cystathionine beta synthase deficiency

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Rao T

2008-01-01

Full Text Available A two year-old male child presented with cutis marmorata congenita universalis, brittle hair, mild mental retardation, and finger spasms. Biochemical findings include increased levels of homocysteine in the blood-106.62 µmol/L (normal levels: 5.90-16µmol/L. Biochemical tests such as the silver nitroprusside and nitroprusside tests were positive suggesting homocystinuria. The patient was treated with oral pyridoxine therapy for three months. The child responded well to this therapy and the muscle spasms as well as skin manifestations such as cutis marmorata subsided. The treatment is being continued; the case is reported here because of its rarity. Homocysteinuria arising due to cystathionine beta-synthase (CBS deficiency is an autosomal recessive disorder of methionine metabolism that produces increased levels of urinary homocysteine and methionine It manifests itself in vascular, central nervous system, cutaneous, and connective tissue disturbances and phenotypically resembles Marfan′s syndrome. Skin manifestations include malar flush, thin hair, and cutis reticulata / marmorata.

The Extracellular Heme-binding Protein HbpS from the Soil Bacterium Streptomyces reticuli Is an Aquo-cobalamin Binder*

Science.gov (United States)

Ortiz de Orué Lucana, Darío; Fedosov, Sergey N.; Wedderhoff, Ina; Che, Edith N.; Torda, Andrew E.

2014-01-01

The extracellular protein HbpS from Streptomyces reticuli interacts with iron ions and heme. It also acts in concert with the two-component sensing system SenS-SenR in response to oxidative stress. Sequence comparisons suggested that the protein may bind a cobalamin. UV-visible spectroscopy confirmed binding (Kd = 34 μm) to aquo-cobalamin (H2OCbl+) but not to other cobalamins. Competition experiments with the H2OCbl+-coordinating ligand CN− and comparison of mutants identified a histidine residue (His-156) that coordinates the cobalt ion of H2OCbl+ and substitutes for water. HbpS·Cobalamin lacks the Asp-X-His-X-X-Gly motif seen in some cobalamin binding enzymes. Preliminary tests showed that a related HbpS protein from a different species also binds H2OCbl+. Furthermore, analyses of HbpS-heme binding kinetics are consistent with the role of HbpS as a heme-sensor and suggested a role in heme transport. Given the high occurrence of HbpS-like sequences among Gram-positive and Gram-negative bacteria, our findings suggest a great functional versatility among these proteins. PMID:25342754

Dietary Methionine Restriction Alleviates Hyperglycemia in Pigs with Intrauterine Growth Restriction by Enhancing Hepatic Protein Kinase B Signaling and Glycogen Synthesis.

Science.gov (United States)

Ying, Zhixiong; Zhang, Hao; Su, Weipeng; Zhou, Le; Wang, Fei; Li, Yue; Zhang, Lili; Wang, Tian

2017-10-01

Background: Individuals with intrauterine growth restriction (IUGR) are prone to developing type 2 diabetes mellitus (T2DM). Dietary methionine restriction (MR) improves insulin sensitivity and glucose homeostasis in individuals with normal birth weight (NBW). Objective: This study investigated the effects of MR on plasma glucose concentration and hepatic and muscle glucose metabolism in pigs with IUGR. Methods: Thirty female NBW and 60 same-sex spontaneous IUGR piglets (Landrace × Yorkshire) were selected. After weaning (day 21), the piglets were fed diets with adequate methionine (NBW-CON and IUGR-CON) or 30% less methionine (IUGR-MR) ( n = 6). At day 180, 1 pig with a body weight near the mean of each replication was selected for biochemical analysis. Results: The IUGR-CON group showed 41.6%, 68.6%, and 67.1% higher plasma glucose concentration, hepatic phosphoenolpyruvate carboxykinase activity, and glucose-6-phosphatase activity, respectively, than the NBW-CON group ( P glycogen content and glycogen synthase activity were 36.9% and 38.8% lower, respectively, in the IUGR-CON than the NBW-CON group ( P glycogen content and glycogen synthase activity of the IUGR-MR pigs were 62.9% and 50.8% higher than those of the IUGR-CON pigs ( P glycogen synthesis, implying a potential nutritional strategy to prevent type 2 diabetes mellitus in IUGR offspring. © 2017 American Society for Nutrition.

Failure to thrive and life-threatening complications due to inherited selective cobalamin malabsorption effectively managed in a juvenile Australian shepherd dog

Science.gov (United States)

Gold, Ashley J.; Scott, Michael A.; Fyfe, John C.

2015-01-01

A juvenile Australian shepherd dog exhibited failure to grow, inappetence, weakness, nonregenerative anemia, neutropenia, and cobalamin deficiency. DNA testing confirmed homozygosity of an amnionless mutation (AMN c.3G > A). Clinical signs resolved with supportive care and parenteral cobalamin supplementation. Inherited selective intestinal cobalamin malabsorption requiring lifelong parenteral supplementation should be considered in Australian shepherds, giant schnauzers, border collies, and beagles that fail to thrive. PMID:26483576

The active site of oxidative phosphorylation and the origin of hyperhomocysteinemia in aging and dementia.

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McCully, Kilmer S

2015-01-01

The active site of oxidative phosphorylation and adenosine triphosphate (ATP) synthesis in mitochondria is proposed to consist of two molecules of thioretinamide bound to cobalamin, forming thioretinaco, complexed with ozone, oxygen, nicotinamide adenine dinucleotide. and inorganic phosphate, TR2CoO3O2NAD(+)H2PO4(-). Reduction of the pyridinium nitrogen of the nicotinamide group by an electron from electron transport complexes initiates polymerization of phosphate with adenosine diphosphate, yielding nicotinamide riboside and ATP bound to thioretinaco ozonide oxygen. A second electron reduces oxygen to hydroperoxyl radical, releasing ATP from the active site. A proton gradient is created within F1F0 ATPase complexes of mitochondria by reaction of protons with reduced nicotinamide riboside and with hydroperoxyl radical, yielding reduced nicotinamide riboside and hydroperoxide. The hyperhomocysteinemia of aging and dementia is attributed to decreased synthesis of adenosyl methionine by thioretinaco ozonide and ATP, causing decreased allosteric activation of cystathionine synthase and decreased allosteric inhibition of methylenetetrahydrofolate reductase and resulting in dysregulation of methionine metabolism. © 2015 by the Association of Clinical Scientists, Inc.

Trans and cis influences and effects in cobalamins and in their simple models.

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De March, Matteo; Demitri, Nicola; Geremia, Silvano; Hickey, Neal; Randaccio, Lucio

2012-11-01

The interligand interactions in coordination compounds have been principally interpreted in terms of cis and trans influences and effects, which can be defined as the ability of a ligand X to affect the bond of another ligand, cis or trans to X, to the metal. This review analyzes these effects/influences in cobalamins (XCbl) and their simple models cobaloximes, LCo(chel)X. Important properties of these complexes, such as geometry, stability, and reactivity, can be rationalized in terms of steric and electronic factors of the ligands. Experimental evidence of normal and inverse trans influence is described in alkylcobaloximes for the first time. The study of simple B(12) models has complemented that on the more complex cobalamins, with particular emphasis on the properties of the axial L-Co-X moiety. Some of the conclusions reached for the axial fragment of simple models have also been qualitatively detected in cobalamins and have furnished new insight into the as yet unestablished mechanism for the homolytic cleavage of the Co - C bond in the AdoCbl-based enzymes. Copyright © 2012 Elsevier Inc. All rights reserved.

Activities of methionine-γ-lyase in the acidophilic archaeon “Ferroplasma acidarmanus” strain fer1

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Khan MA

2013-04-01

Full Text Available M A Khan,1 Madeline M López-Muñoz,2 Charles W Kaspar,3 Kai F Hung1 1Department of Biological Sciences, Eastern Illinois University, Charleston, IL, USA; 2Department of Biology, Universidad de Puerto Rico, Mayaguez, Puerto Rico; 3Bacteriology Department, University of Wisconsin, Madison, WI, USA Abstract: Biogeochemical processes on exposed pyrite ores result in extremely high levels of sulfuric acid at these locations. Acidophiles that thrive in these conditions must overcome significant challenges, including an environment with proton concentrations at pH 3 or below. The role of sulfur metabolism in the archaeon “Ferroplasma acidarmanus” strain fer1's ability to thrive in this environment was investigated due to its growth-dependent production of methanethiol, a volatile organic sulfur compound. Two putative sequences for methionine-γ-lyase (EC 4.4.1.11, an enzyme known to carry out α, γ-elimination on L-methionine to produce methanethiol, were identified in fer1. Bioinformatic analyses identified a conserved pyridoxal-5'-phosphate (PLP binding domain and a partially conserved catalytic domain in both putative sequences. Detection of PLP-dependent and L-methionine-dependent production of α-keto compounds and thiol groups in fer1 confirmed the presence of methionine-γ-lyase activity. Further, fer1 lysate was capable of processing related substrates, including D-methionine, L-cysteine, L-cystathionine, and L/D-homocysteine. When the two putative fer1 methionine-γ-lyase gene-coded proteins were expressed in Escherichia coli cells, one sequence demonstrated an ability to carry out α, γ-elimination activity, while the other exhibited γ-replacement activity. These fer1 methionine-γ-lyases also exhibited optimum pH, substrate specificity, and catalytic preferences that are different from methionine-γ-lyases from other organisms. These differences are discussed in the context of molecular phylogeny constructed using a maximum

The methionine salvage pathway in Bacillus subtilis

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Danchin Antoine

2002-04-01

Full Text Available Abstract Background Polyamine synthesis produces methylthioadenosine, which has to be disposed of. The cell recycles it into methionine through methylthioribose (MTR. Very little was known about MTR recycling for methionine salvage in Bacillus subtilis. Results Using in silico genome analysis and transposon mutagenesis in B. subtilis we have experimentally uncovered the major steps of the dioxygen-dependent methionine salvage pathway, which, although similar to that found in Klebsiella pneumoniae, recruited for its implementation some entirely different proteins. The promoters of the genes have been identified by primer extension, and gene expression was analyzed by Northern blotting and lacZ reporter gene expression. Among the most remarkable discoveries in this pathway is the role of an analog of ribulose diphosphate carboxylase (Rubisco, the plant enzyme used in the Calvin cycle which recovers carbon dioxide from the atmosphere as a major step in MTR recycling. Conclusions A complete methionine salvage pathway exists in B. subtilis. This pathway is chemically similar to that in K. pneumoniae, but recruited different proteins to this purpose. In particular, a paralogue or Rubisco, MtnW, is used at one of the steps in the pathway. A major observation is that in the absence of MtnW, MTR becomes extremely toxic to the cell, opening an unexpected target for new antimicrobial drugs. In addition to methionine salvage, this pathway protects B. subtilis against dioxygen produced by its natural biotope, the surface of leaves (phylloplane.

Iron, folate and cobalamin deficiency in anaemic pregnant females in tertiary care centre at Rawalpindi

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Khan, D A; Fatima, S; Imran, R; Khan, F A [National Univ. of Science and Technology, Army Medical College, Rawalpindi (Pakistan). Department of Pathology

2010-01-15

Background: Anaemia in pregnancy is a common clinical problem contributing to increased maternal and foetal morbidity. This study was carried out to determine frequency of iron, folate and cobalamin deficiency and associated risk factors in the anaemic pregnant females who reported first time during second and third trimester for antenatal check-up in the tertiary care hospital at Rawalpindi. Methods: This case control study was carried out in a tertiary care hospital at Rawalpindi. Two hundred and fifty pregnant women (age: 19-43 years) consisting of 125 anaemic (Hb< 110 g/L) and 125 non-anaemic who reported first time at antenatal clinic were included. Data on socio-demographic characteristics, parity and dietary intake were collected. Complete blood counts were done. Serum ferritin, folate and cobalamin assays were performed by using DPC kits on Immulite-1000. Results: The pregnant women were categorised having mild (Hb up to 54%), moderate (Hb up to 36%), or severe (Hb up to 10%) anaemia during antennal visit. They had significantly lower median (range) levels of haemoglobin 96 (40-110) g/L, ferritin 8 (3-54) nu mu/L, folate 15 (3-54) mu mol/L and cobalamin 171 (111-629) mu mol/L than controls (p=<0.01). Micro nutrient analysis revealed secondary pregnancy related deficiency of Iron (57%), folate (20%), combined iron and folate (19%) and cobalamin (4%) in the female. Among the risk factors, low income (OR: 7.69), multi party (OR: 2.93), lack of iron/folate supplementation (OR 2.91) and inadequate dietary intakes (OR 2.51) were associated with anaemia. Conclusion: The pregnant anaemic women had iron (57%); folate (20%), followed by combined iron folate (19%), and cobalamin (4%) deficiency during first antenatal visit. Low income, multi party, poor diet and lack of supplements are the main contributor in development of anaemia during pregnancy. (author)

Iron, folate and cobalamin deficiency in anaemic pregnant females in tertiary care centre at Rawalpindi

International Nuclear Information System (INIS)

Khan, D.A.; Fatima, S.; Imran, R.; Khan, F.A.

2010-01-01

Background: Anaemia in pregnancy is a common clinical problem contributing to increased maternal and foetal morbidity. This study was carried out to determine frequency of iron, folate and cobalamin deficiency and associated risk factors in the anaemic pregnant females who reported first time during second and third trimester for antenatal check-up in the tertiary care hospital at Rawalpindi. Methods: This case control study was carried out in a tertiary care hospital at Rawalpindi. Two hundred and fifty pregnant women (age: 19-43 years) consisting of 125 anaemic (Hb< 110 g/L) and 125 non-anaemic who reported first time at antenatal clinic were included. Data on socio-demographic characteristics, parity and dietary intake were collected. Complete blood counts were done. Serum ferritin, folate and cobalamin assays were performed by using DPC kits on Immulite-1000. Results: The pregnant women were categorised having mild (Hb up to 54%), moderate (Hb up to 36%), or severe (Hb up to 10%) anaemia during antennal visit. They had significantly lower median (range) levels of haemoglobin 96 (40-110) g/L, ferritin 8 (3-54) nu mu/L, folate 15 (3-54) mu mol/L and cobalamin 171 (111-629) mu mol/L than controls (p=<0.01). Micro nutrient analysis revealed secondary pregnancy related deficiency of Iron (57%), folate (20%), combined iron and folate (19%) and cobalamin (4%) in the female. Among the risk factors, low income (OR: 7.69), multi party (OR: 2.93), lack of iron/folate supplementation (OR 2.91) and inadequate dietary intakes (OR 2.51) were associated with anaemia. Conclusion: The pregnant anaemic women had iron (57%); folate (20%), followed by combined iron folate (19%), and cobalamin (4%) deficiency during first antenatal visit. Low income, multi party, poor diet and lack of supplements are the main contributor in development of anaemia during pregnancy. (author)

Calcium Co-regulates Oxidative Metabolism and ATP Synthase-dependent Respiration in Pancreatic Beta Cells

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De Marchi, Umberto; Thevenet, Jonathan; Hermant, Aurelie; Dioum, Elhadji; Wiederkehr, Andreas

2014-01-01

Mitochondrial energy metabolism is essential for glucose-induced calcium signaling and, therefore, insulin granule exocytosis in pancreatic beta cells. Calcium signals are sensed by mitochondria acting in concert with mitochondrial substrates for the full activation of the organelle. Here we have studied glucose-induced calcium signaling and energy metabolism in INS-1E insulinoma cells and human islet beta cells. In insulin secreting cells a surprisingly large fraction of total respiration under resting conditions is ATP synthase-independent. We observe that ATP synthase-dependent respiration is markedly increased after glucose stimulation. Glucose also causes a very rapid elevation of oxidative metabolism as was followed by NAD(P)H autofluorescence. However, neither the rate of the glucose-induced increase nor the new steady-state NAD(P)H levels are significantly affected by calcium. Our findings challenge the current view, which has focused mainly on calcium-sensitive dehydrogenases as the target for the activation of mitochondrial energy metabolism. We propose a model of tight calcium-dependent regulation of oxidative metabolism and ATP synthase-dependent respiration in beta cell mitochondria. Coordinated activation of matrix dehydrogenases and respiratory chain activity by calcium allows the respiratory rate to change severalfold with only small or no alterations of the NAD(P)H/NAD(P)+ ratio. PMID:24554722

In Salmonella enterica, the Gcn5-Related Acetyltransferase MddA (Formerly YncA) Acetylates Methionine Sulfoximine and Methionine Sulfone, Blocking Their Toxic Effects

Science.gov (United States)

Hentchel, Kristy L.

2014-01-01

Protein and small-molecule acylation reactions are widespread in nature. Many of the enzymes catalyzing acylation reactions belong to the Gcn5-related N-acetyltransferase (GNAT; PF00583) family, named after the yeast Gcn5 protein. The genome of Salmonella enterica serovar Typhimurium LT2 encodes 26 GNATs, 11 of which have no known physiological role. Here, we provide in vivo and in vitro evidence for the role of the MddA (methionine derivative detoxifier; formerly YncA) GNAT in the detoxification of oxidized forms of methionine, including methionine sulfoximine (MSX) and methionine sulfone (MSO). MSX and MSO inhibited the growth of an S. enterica ΔmddA strain unless glutamine or methionine was present in the medium. We used an in vitro spectrophotometric assay and mass spectrometry to show that MddA acetylated MSX and MSO. An mddA+ strain displayed biphasic growth kinetics in the presence of MSX and glutamine. Deletion of two amino acid transporters (GlnHPQ and MetNIQ) in a ΔmddA strain restored growth in the presence of MSX. Notably, MSO was transported by GlnHPQ but not by MetNIQ. In summary, MddA is the mechanism used by S. enterica to respond to oxidized forms of methionine, which MddA detoxifies by acetyl coenzyme A-dependent acetylation. PMID:25368301

Role of the transsulfuration pathway and of gamma-cystathionase activity in the formation of cysteine and sulfate from methionine in rat hepatocytes

International Nuclear Information System (INIS)

Rao, A.M.; Drake, M.R.; Stipanuk, M.H.

1990-01-01

To assess the extent to which low hepatic gamma-cystathionase levels affect methionine flux to cysteine in hepatocytes, the effect of inhibition of gamma-cystathionase activity with propargylglycine on the metabolism of L-[ 35 S]methionine was determined in studies with freshly isolated rat hepatocytes. gamma-Cystathionase activity was inhibited 25%, 42%, 63% and 76% (maximal inhibition) by treatment with 2.5 mumol/L, 0.01 mmol/L, 0.02 mmol/L and 2 mmol/l propargylglycine, respectively. Inhibition of gamma-cystathionase activity with up to 0.02 mmol/L propargylglycine had no statistically significant effect on [ 35 S]glutathione, [ 35 S]sulfate or [ 35 S]cysteine formation from [ 35 S]methionine. However, treatment of cells with 2 mmol/L propargylglycine markedly inhibited the metabolism of [ 35 S]methionine to [ 35 S]glutathione by 93%, to [ 35 S]sulfate by 88% and to [ 35 S]cysteine by 89%; [ 35 S]cystathionine accumulation in these incubation systems was 60 times control. Hepatic gamma-cystathionase activity in premature infants has been reported to be about 23% of mature levels; this level of gamma-cystathionase activity may limit cysteine synthesis by the methionine transsulfuration pathway. No evidence for cysteine synthesis from serine and sulfide, which can be catalyzed by cystathionine beta-synthase, or for methionine metabolism by an S-adenosylmethionine-independent pathway was obtained

Metagenomic and Metatranscriptomic Analyses Reveal the Structure and Dynamics of a Dechlorinating Community Containing Dehalococcoides mccartyi and Corrinoid-Providing Microorganisms under Cobalamin-Limited Conditions

Energy Technology Data Exchange (ETDEWEB)

Men, Yujie; Yu, Ke; Bælum, Jacob; Gao, Ying; Tremblay, Julien; Prestat, Emmanuel; Stenuit, Ben; Tringe, Susannah G.; Jansson, Janet; Zhang, Tong; Alvarez-Cohen, Lisa; Liu, Shuang-Jiang

2017-02-10

The aim of this study is to obtain a systems-level understanding of the interactions betweenDehalococcoidesand corrinoid-supplying microorganisms by analyzing community structures and functional compositions, activities, and dynamics in trichloroethene (TCE)-dechlorinating enrichments. Metagenomes and metatranscriptomes of the dechlorinating enrichments with and without exogenous cobalamin were compared. Seven putative draft genomes were binned from the metagenomes. At an early stage (2 days), more transcripts of genes in theVeillonellaceaebin-genome were detected in the metatranscriptome of the enrichment without exogenous cobalamin than in the one with the addition of cobalamin. Among these genes, sporulation-related genes exhibited the highest differential expression when cobalamin was not added, suggesting a possible release route of corrinoids from corrinoid producers. Other differentially expressed genes include those involved in energy conservation and nutrient transport (including cobalt transport). The most highly expressed corrinoidde novobiosynthesis pathway was also assigned to theVeillonellaceaebin-genome. Targeted quantitative PCR (qPCR) analyses confirmed higher transcript abundances of those corrinoid biosynthesis genes in the enrichment without exogenous cobalamin than in the enrichment with cobalamin. Furthermore, the corrinoid salvaging and modification pathway ofDehalococcoideswas upregulated in response to the cobalamin stress. This study provides important insights into the microbial interactions and roles played by members of dechlorinating communities under cobalamin-limited conditions.

IMPORTANCEThe key

Plant oxidosqualene metabolism: cycloartenol synthase-dependent sterol biosynthesis in Nicotiana benthamiana.

Science.gov (United States)

Gas-Pascual, Elisabet; Berna, Anne; Bach, Thomas J; Schaller, Hubert

2014-01-01

The plant sterol pathway exhibits a major biosynthetic difference as compared with that of metazoans. The committed sterol precursor is the pentacyclic cycloartenol (9β,19-cyclolanost-24-en-3β-ol) and not lanosterol (lanosta-8,24-dien-3β-ol), as it was shown in the late sixties. However, plant genome mining over the last years revealed the general presence of lanosterol synthases encoding sequences (LAS1) in the oxidosqualene cyclase repertoire, in addition to cycloartenol synthases (CAS1) and to non-steroidal triterpene synthases that contribute to the metabolic diversity of C30H50O compounds on earth. Furthermore, plant LAS1 proteins have been unambiguously identified by peptidic signatures and by their capacity to complement the yeast lanosterol synthase deficiency. A dual pathway for the synthesis of sterols through lanosterol and cycloartenol was reported in the model Arabidopsis thaliana, though the contribution of a lanosterol pathway to the production of 24-alkyl-Δ(5)-sterols was quite marginal (Ohyama et al. (2009) PNAS 106, 725). To investigate further the physiological relevance of CAS1 and LAS1 genes in plants, we have silenced their expression in Nicotiana benthamiana. We used virus induced gene silencing (VIGS) based on gene specific sequences from a Nicotiana tabacum CAS1 or derived from the solgenomics initiative (http://solgenomics.net/) to challenge the respective roles of CAS1 and LAS1. In this report, we show a CAS1-specific functional sterol pathway in engineered yeast, and a strict dependence on CAS1 of tobacco sterol biosynthesis.

Nutriepigenetic regulation by folate-homocysteine-methionine axis: a review.

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Bhargava, Seema; Tyagi, S C

2014-02-01

Although normally folic acid is given during pregnancy, presumably to prevent neural tube defects, the mechanisms of this protection are unknown. More importantly it is unclear whether folic acid has other function during development. It is known that folic acid re-methylates homocysteine (Hcy) to methionine by methylene tetrahydrofolate reductase-dependent pathways. Folic acid also generates high-energy phosphates, behaves as an antioxidant and improves nitric oxide (NO) production by endothelial NO synthase. Interestingly, during epigenetic modification, methylation of DNA/RNA generate homocysteine unequivocally. The enhanced overexpression of methyl transferase lead to increased yield of Hcy. The accumulation of Hcy causes vascular dysfunction, reduces perfusion in the muscles thereby causing musculopathy. Another interesting fact is that children with severe hyperhomocysteinaemia (HHcy) have skeletal deformities, and do not live past teenage. HHcy is also associated with the progeria syndrome. Epilepsy is primarily caused by inhibition of gamma-amino-butyric-acid (GABA) receptor, an inhibitory neurotransmitter in the neuronal synapse. Folate deficiency leads to HHcy which then competes with GABA for binding on the GABA receptors. With so many genetic and clinical manifestations associated with folate deficiency, we propose that folate deficiency induces epigenetic alterations in the genes and thereby results in disease.

Increase in circulating holotranscobalamin after oral administration of cyanocobalamin or hydroxocobalamin in healthy adults with low and normal cobalamin status

DEFF Research Database (Denmark)

Greibe, Eva; Mahalle, Namita; Bhide, Vijayshri

2017-01-01

PURPOSE: To investigate the absorption of synthetic cyanocobalamin and natural occurring hydroxocobalamin in populations with low and normal cobalamin (vitamin B12) status. METHODS: We included adults with low (n = 59) and normal (n = 42) cobalamin status and measured the change in serum holotran...

Cobalamins uncovered by modern electronic structure calculations

DEFF Research Database (Denmark)

Kepp, Kasper Planeta; Ryde, Ulf

2009-01-01

electronic-structure calculations, in particular density functional methods, the understanding of the molecular mechanism of cobalamins has changed dramatically, going from a dominating view of trans-steric strain effects to a much more complex view involving an arsenal of catalytic strategies. Among...... these are cis-steric distortions, electrostatic stabilization of radical products, the realization that nucleotide units can serve as polar handles, and the careful design of the active sites, with polar residues in the radical enzymes and non-polar residues in the transferases. Together, these strategies...

Bacterial variations on the methionine salvage pathway

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Haas Dieter

2004-03-01

Full Text Available Abstract Background The thiomethyl group of S-adenosylmethionine is often recycled as methionine from methylthioadenosine. The corresponding pathway has been unravelled in Bacillus subtilis. However methylthioadenosine is subjected to alternative degradative pathways depending on the organism. Results This work uses genome in silico analysis to propose methionine salvage pathways for Klebsiella pneumoniae, Leptospira interrogans, Thermoanaerobacter tengcongensis and Xylella fastidiosa. Experiments performed with mutants of B. subtilis and Pseudomonas aeruginosa substantiate the hypotheses proposed. The enzymes that catalyze the reactions are recruited from a variety of origins. The first, ubiquitous, enzyme of the pathway, MtnA (methylthioribose-1-phosphate isomerase, belongs to a family of proteins related to eukaryotic intiation factor 2B alpha. mtnB codes for a methylthioribulose-1-phosphate dehydratase. Two reactions follow, that of an enolase and that of a phosphatase. While in B. subtilis this is performed by two distinct polypeptides, in the other organisms analyzed here an enolase-phosphatase yields 1,2-dihydroxy-3-keto-5-methylthiopentene. In the presence of dioxygen an aci-reductone dioxygenase yields the immediate precursor of methionine, ketomethylthiobutyrate. Under some conditions this enzyme produces carbon monoxide in B. subtilis, suggesting a route for a new gaseous mediator in bacteria. Ketomethylthiobutyrate is finally transaminated by an aminotransferase that exists usually as a broad specificity enzyme (often able to transaminate aromatic aminoacid keto-acid precursors or histidinol-phosphate. Conclusion A functional methionine salvage pathway was experimentally demonstrated, for the first time, in P. aeruginosa. Apparently, methionine salvage pathways are frequent in Bacteria (and in Eukarya, with recruitment of different polypeptides to perform the needed reactions (an ancestor of a translation initiation factor and Ru

Evolution of the key alkaloid enzyme putrescine N-methyltransferase from spermidine synthase.

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Anne eJunker

2013-07-01

Full Text Available Putrescine N-methyltransferases (PMTs are the first specific enzymes of the biosynthesis of nicotine and tropane alkaloids. PMTs transfer a methyl group onto the diamine putrescine from S-adenosyl-L-methionine (SAM as coenzyme. PMT proteins have presumably evolved from spermidine synthases (SPDSs, which are ubiquitous enzymes of polyamine metabolism. SPDS use decarboxylated SAM as coenzyme to transfer an aminopropyl group onto putrescine. In an attempt to identify possible and necessary steps in the evolution of PMT from SPDS, homology based modeling of Datura stramonium SPDS1 and PMT was employed to gain deeper insight in the preferred binding positions and conformations of the substrate and the alternative coenzymes. Based on predictions of amino acids responsible for the change of enzyme specificities, sites of mutagenesis were derived. PMT activity was generated in Datura stramonium SPDS1 after few amino acid exchanges. Concordantly, Arabidopsis thaliana SPDS1 was mutated and yielded enzymes with both, PMT and SPDS activities. Kinetic parameters were measured for enzymatic characterization. The switch from aminopropyl to methyl transfer depends on conformational changes of the methionine part of the coenzyme in the binding cavity of the enzyme. The rapid generation of PMT activity in SPDS proteins and the wide-spread occurrence of putative products of N-methylputrescine suggest that PMT activity is present frequently in the plant kingdom.

Reductive dehalogenase structure suggests a mechanism for B12-dependent dehalogenation.

Science.gov (United States)

Payne, Karl Ap; Quezada, Carolina P; Fisher, Karl; Dunstan, Mark S; Collins, Fraser A; Sjuts, Hanno; Levy, Colin; Hay, Sam; Rigby, Stephen Ej; Leys, David

2015-01-22

Organohalide chemistry underpins many industrial and agricultural processes, and a large proportion of environmental pollutants are organohalides. Nevertheless, organohalide chemistry is not exclusively of anthropogenic origin, with natural abiotic and biological processes contributing to the global halide cycle. Reductive dehalogenases are responsible for biological dehalogenation in organohalide respiring bacteria, with substrates including polychlorinated biphenyls or dioxins. Reductive dehalogenases form a distinct subfamily of cobalamin (B12)-dependent enzymes that are usually membrane associated and oxygen sensitive, hindering detailed studies. Here we report the characterization of a soluble, oxygen-tolerant reductive dehalogenase and, by combining structure determination with EPR (electron paramagnetic resonance) spectroscopy and simulation, show that a direct interaction between the cobalamin cobalt and the substrate halogen underpins catalysis. In contrast to the carbon-cobalt bond chemistry catalysed by the other cobalamin-dependent subfamilies, we propose that reductive dehalogenases achieve reduction of the organohalide substrate via halogen-cobalt bond formation. This presents a new model in both organohalide and cobalamin (bio)chemistry that will guide future exploitation of these enzymes in bioremediation or biocatalysis.

Transient plasma cobalamin elevation in patients with pneumonia - two case reports

DEFF Research Database (Denmark)

Rahbek, Martin Torp; Scheller, Rudolf; Nybo, Mads

2018-01-01

We report two cases of transient significantly elevated plasma cobalamin (B12) in geriatric patients acutely admitted with fever, increased C-reactive protein and X-ray verified pneumonia. Extensive diagnostic workup did not reveal kidney or liver disease, neither any signs of cancer. Furthermore...

Methionine metabolism in apple tissue: implications of S-adenosylmethionine as an intermediate in the conversion of methionine to ethylene

International Nuclear Information System (INIS)

Adams, D.O.; Yang, S.F.

1977-01-01

If S-adenosylmethionine (SAM) is the direct precursor of ethylene as previously proposed, it is expected that 5'-S-methyl-5'-thioadenosine (MTA) would be the fragment nucleoside. When [Me- 14 C] or ( 35 S)methionine was fed to climacteric apple (Malus sylvestris Mill) tissue, radioactive 5-S-methyl-5-thioribose (MTR) was identified as the predominant product and MTA as a minor one. When the conversion of methionine into ethylene was inhibited by L-2-amino-4-(2'-amino-ethoxy)-trans-3-butenoic acid, the conversion of ( 35 S) or (Me- 14 C)methionine into MTR was similarly inhibited. Furthermore, the formation of MTA and MTR from ( 35 S)methionine was observed only in climacteric tissue which produced ethylene and actively converted methionine to ethylene but not in preclimacteric tissue which did not produce ethylene or convert methionine to ethylene. These observations suggest that the conversion of methionine into MTA and MTR is closely related to ethylene biosynthesis and provide indirect evidence that SAM may be an intermediate in the conversion of methionine to ethylene. When ( 35 S)MTA was fed to climacteric or preclimacteric apple tissue, radioactivity was efficiently incorporated into MTR and methionine. However, when ( 35 S)MTR was administered, radioactivity was efficiently incorporated into methionine but not MTA. A scheme is presented for the production of ethylene from methionine

A common transport system for methionine, L-methionine-DL-sulfoximine (MSX), and phosphinothricin (PPT) in the diazotrophic cyanobacterium Nostoc muscorum.

Science.gov (United States)

Singh, Arvind Kumar; Syiem, Mayashree B; Singh, Rajkumar S; Adhikari, Samrat; Rai, Amar Nath

2008-05-01

We present evidence, for the first time, of the occurrence of a transport system common for amino acid methionine, and methionine/glutamate analogues L-methionine-DL-sulfoximine (MSX) and phosphinothricin (PPT) in cyanobacterium Nostoc muscorum. Methionine, which is toxic to cyanobacterium, enhanced its nitrogenase activity at lower concentrations. The cyanobacterium showed a biphasic pattern of methionine uptake activity that was competitively inhibited by the amino acids alanine, isoleucine, leucine, phenylalanine, proline, valine, glutamine, and asparagine. The methionine/glutamate analogue-resistant N. muscorum strains (MSX-R and PPT-R strains) also showed methionine-resistant phenotype accompanied by a drastic decrease in 35S methionine uptake activity. Treatment of protein extracts from these mutant strains with MSX and PPT reduced biosynthetic glutamine synthetase (GS) activity only in vitro and not in vivo. This finding implicated that MSX- and PPT-R phenotypes may have arisen due to a defect in their MSX and PPT transport activity. The simultaneous decrease in methionine uptake activity and in vitro sensitivity toward MSX and PPT of GS protein in MSX- and PPT-R strains indicated that methionine, MSX, and PPT have a common transport system that is shared by other amino acids as well in N. muscorum. Such information can become useful for isolation of methionine-producing cyanobacterial strains.

Heme A synthase in bacteria depends on one pair of cysteinyls for activity.

Science.gov (United States)

Lewin, Anna; Hederstedt, Lars

2016-02-01

Heme A is a prosthetic group unique for cytochrome a-type respiratory oxidases in mammals, plants and many microorganisms. The poorly understood integral membrane protein heme A synthase catalyzes the synthesis of heme A from heme O. In bacteria, but not in mitochondria, this enzyme contains one or two pairs of cysteine residues that are present in predicted hydrophilic polypeptide loops on the extracytoplasmic side of the membrane. We used heme A synthase from the eubacterium Bacillus subtilis and the hyperthermophilic archeon Aeropyrum pernix to investigate the functional role of these cysteine residues. Results with B. subtilis amino acid substituted proteins indicated the pair of cysteine residues in the loop connecting transmembrane segments I and II as being essential for catalysis but not required for binding of the enzyme substrate, heme O. Experiments with isolated A. pernix and B. subtilis heme A synthase demonstrated that a disulfide bond can form between the cysteine residues in the same loop and also between loops showing close proximity of the two loops in the folded enzyme protein. Based on the findings, we propose a classification scheme for the four discrete types of heme A synthase found so far in different organisms and propose that essential cysteinyls mediate transfer of reducing equivalents required for the oxygen-dependent catalysis of heme A synthesis from heme O. Copyright © 2015 Elsevier B.V. All rights reserved.

Growth inhibition of Chromatium D by L-methionine and its correlation to unusual accumulation of S-adenosyl-L-methionine in the cell

Energy Technology Data Exchange (ETDEWEB)

Sugimoto, Y; Nakatani, K; Shirakashi, T; Ohmori, H; Toraya, T [Kyoto Univ. (Japan). Faculty of Engineering

1976-07-01

L-Methionine strongly inhibited the growth of Chromatium D when added at a low concentration to the growth medium containing both sulfide and thiosulfate. S-Adenosyl-L-methionine inhibited the growth, irrespective of the coexistence of sulfide and thiosulfate. Upon addition of L-methionine to the growth media, the presence of both sulfide and thiosulfate in the media stimulated the in vivo conversion of L-methionine to S-adenosyl-L-methionine, and consequently increased the intracellular level of S-adenosyl-L-methionine. From these data, it was strongly suggested that the unusual accumulation of S-adenosyl-L-methionine in the cells of Chromatium D is responsible for the growth inhibition by L-methionine. The level of S-adenosyl-L-methionine synthetase (ATP: L-methionine S-adenosyltransferase, EC2.5.16) was significantly enhanced by adding L-methionine, sulfide and thiosulfate to the growth medium.

Partitioning of One-Carbon Units in Folate and Methionine Metabolism Is Essential for Neural Tube Closure

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Kit-Yi Leung

2017-11-01

Full Text Available Summary: Abnormal folate one-carbon metabolism (FOCM is implicated in neural tube defects (NTDs, severe malformations of the nervous system. MTHFR mediates unidirectional transfer of methyl groups from the folate cycle to the methionine cycle and, therefore, represents a key nexus in partitioning one-carbon units between FOCM functional outputs. Methionine cycle inhibitors prevent neural tube closure in mouse embryos. Similarly, the inability to use glycine as a one-carbon donor to the folate cycle causes NTDs in glycine decarboxylase (Gldc-deficient embryos. However, analysis of Mthfr-null mouse embryos shows that neither S-adenosylmethionine abundance nor neural tube closure depend on one-carbon units derived from embryonic or maternal folate cycles. Mthfr deletion or methionine treatment prevents NTDs in Gldc-null embryos by retention of one-carbon units within the folate cycle. Overall, neural tube closure depends on the activity of both the methionine and folate cycles, but transfer of one-carbon units between the cycles is not necessary. : Leung at al. find that embryonic neural tube closure depends both on the supply of one-carbon units to the folate cycle from glycine cleavage and on the methionine cycle. In contrast, transfer of one-carbon units from the folate cycle to the methionine cycle by MTHFR is dispensable. Keywords: one-carbon metabolism, folic acid, neural tube defects, spina bifida, glycine cleavage system, non-ketotic hyperglycinemia, eye, Mthfr, Gldc

A Rich Man, Poor Man Story of S-Adenosylmethionine and Cobalamin Revisited.

Science.gov (United States)

Bridwell-Rabb, Jennifer; Grell, Tsehai A J; Drennan, Catherine L

2018-06-20

S-adenosylmethionine (AdoMet) has been referred to as both "a poor man's adenosylcobalamin (AdoCbl)" and "a rich man's AdoCbl," but today, with the ever-increasing number of functions attributed to each cofactor, both appear equally rich and surprising. The recent characterization of an organometallic species in an AdoMet radical enzyme suggests that the line that differentiates them in nature will be constantly challenged. Here, we compare and contrast AdoMet and cobalamin (Cbl) and consider why Cbl-dependent AdoMet radical enzymes require two cofactors that are so similar in their reactivity. We further carry out structural comparisons employing the recently determined crystal structure of oxetanocin-A biosynthetic enzyme OxsB, the first three-dimensional structural data on a Cbl-dependent AdoMet radical enzyme. We find that the structural motifs responsible for housing the AdoMet radical machinery are largely conserved, whereas the motifs responsible for binding additional cofactors are much more varied.

Lack of association between methionine synthase A2756G polymorphism and digestive system cancer risk: evidence from 3,9327 subjects.

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Yuan Zhao

Full Text Available BACKGROUND: Polymorphisms in genes involved in the metabolism of folate and methyl groups have been implicated with risk of digestive system cancer. Methionine synthase (MTR plays a central role in folate metabolism, thereby affecting DNA methylation. The association between A2756G polymorphism (rs1805087 in MTR and digestive system cancer susceptibility was inconsistent in previous studies. To investigate this inconsistency, we performed this meta-analysis. METHODS: Databases including Pubmed, EMBASE, ISI Web of Science and China National Knowledge Infrastructure (CNKI were searched to find relevant studies. Odds ratios (ORs with 95% confidence intervals (CIs were used to assess the strength of association. Potential sources of heterogeneity were also assessed by subgroup analysis and meta-regression. RESULTS: A total of 29 articles with 15,368 patients and 23,959 controls were included. We found no association between MTR A2756G polymorphism and digestive system cancer in overall population (G allele: OR = 1.03, 95% CI = 0.98-1.09, P = 0.25; dominant model: OR = 1.03, 95% CI = 0.97-1.10, P = 0.33; recessive model: OR = 1.02, 95% CI = 0.89-1.17, P = 0.79. In the stratified analyses according to cancer type, sample size and genotyping method, no evidence of any gene-disease association was obtained in almost all genetic models. However, marginal significant associations were found for East Asians and hospital-based studies. CONCLUSIONS: This meta-analysis suggests that there is no significant association between the MTR A2756G polymorphism and digestive system cancer risk.

A kinetic and mechanistic study on the oxidation of l-methionine and N-acetyl l-methionine by cerium(IV) in sulfuric acid medium

OpenAIRE

T. Sumathi; P. Shanmugasundaram; G. Chandramohan

2016-01-01

The kinetics of oxidation of l-methionine and N-acetyl l-methionine by Ce(IV) in sulfuric acid–sulfate media in the range of 288.1–298.1 K has been investigated. The major oxidation products of methionine and N-acetyl l-methionine have been identified as methionine sulfoxide and N-acetyl methionine sulfoxide. The major oxidation products have been confirmed by qualitative analysis and boiling point. The reaction was first order with respect to l-methionine, N-acetyl l-methionine and Ce(IV). I...

Factors influencing methionine toxicity in young bobwhite quail

Science.gov (United States)

Serafin, J.A.

1981-01-01

Young Bobwhite quail (Colinus virginianus) were fed low and adequate protein purified diets with and without excess methionine to evaluate factors affecting methionine toxicity. Growth of quail fed an adequate protein (27%) diet, without supplemental glycine, was depressed by 1.75% and 2.25% excess methionine. Supplemental glycine (.3%) alleviated growth depression caused by 2.25% excess methionine. Quail fed 1.75% and 2.25% excess methionine developed signs of toxicity characterized by weakness, a lowered, outstretched neck when moving, and ataxia. In addition, quail would fall on their sides when disturbed and spin with their heads retracted. These conditions were transient in nature. Growth of quail fed a low protein (18.9%) diet was depressed by 1% and 1.5% excess methionine and DL-homocystine. Quail fed 1% and 1.5% excess methionine in this diet also developed signs of toxicity, the incidence of which was greater and the duration longer than occurred with quail fed adequate protein. Supplementing a low protein (20.15%) diet with .3% or .6% glycine or threonine or a combination of these amino acids did not alleviate growth depression caused by 1.5% excess methionine; however, 2% and 3% supplemental glycine were somewhat effective. Supplements of glycine (2%, 3%) and threonine (1%) completely reversed growth depression from 1% excess methionine but did not influence growth of controls, indicating that both amino acids counteract methionine toxicity. Both glycine and threonine alone improved growth by about the same extent in diets with 1% or 1.5% excess methionine; however, these amino acids alleviated less than 30% of the growth depression resulting from 1.5% excess methionine. The effectiveness of glycine in alleviating methionine toxicity in a low protein diet was decreased, and hemoglobin levels were depressed with 1.5% excess methionine compared to less amounts.

Characterization and sequencing of the active site of 1-aminocyclopropane-1-carboxylate synthase

International Nuclear Information System (INIS)

Yip, Wing-Kin; Dong, Jian-Guo; Yang, S.F.; Kenny, J.W.; Thompson, G.A.

1990-01-01

The pyridoxal phosphate (PLP)-dependent 1-aminocyclopropane-1-carboxylic acid (ACC) synthase the key enzyme in ethylene biosynthesis, is inactivated by its substrate S-adenosylmethionine (AdoMet). Apple ACC synthase was purified with an immunoaffinity gel, and its active site was probed with NaB 3 H 4 or Ado[ 14 C]Met. Peptide sequencing of both 3 H- and 14 C-labeled peptides revealed a common dodecapeptide of Ser-Leu-Ser-Xaa-Asp-Leu-Gly-Leu-Pro-Gly-Phe-Arg, where Xaa was the modified, radioactive residue in each case. Acid hydrolysis of the 3 H-labeled enzyme released radioactive N-pyridoxyllysine, indicating that the active-site peptide contained lysine at position 4. Mass spectrometry of the 14 C-labeled peptide indicated a protonated molecular ion at m/z 1390.6, from which the mass of Xaa was calculated to be 229, a number that is equivalent to the mass of a lysine residue alkylated by the 2-aminobutyrate portion of AdoMet, as we previously proposed. These results indicate that the same active-site lysine binds the PLP and convalently links to the 2-aminobutyrate portion of AdoMet during inactivation. The active site of tomato ACC synthase was probed in the same manner with Ado [ 14 C]Met. Sequencing of the tomato active-site peptide revealed two highly conserved dodecapeptides; the minor peptide possessed a sequence identical to that of the apple enzyme, whereas the major peptide differed from the minor peptide in that methionine replaced leucine at position 6

Metabolism of 5-methylthioribose to methionine

International Nuclear Information System (INIS)

Miyazaki, J.H.; Yang, S.F.

1987-01-01

During ethylene biosynthesis, the H 3 CS-group of S-adenosylmethionine is released as 5'-methylthioadenosine, which is recycled to methionine via 5-methylthioribose (MTR). In mungbean hypocotyls and cell-free extracts of avocado, [ 14 C]MTR was converted into labeled methionine via 2-keto-4-methylthiobutyric acid (KMB) and 2-hydroxy-4-methylthiobutyric acid (HMB), as intermediates. Incubation of [ribose-U- 14 C]MTR with avocado extract resulted in the production of [ 14 C]formate, indicating the conversion of MTR to KMB involves a loss of formate, presumably from C-1 of MTR. Tracer studies showed that KMB was converted readily in vivo and in vitro to methionine, while HMB was converted much more slowly. The conversion of KMB to methionine by dialyzed avocado extract requires an amino donor. Among several potential donors examined, L-glutamine was the most efficient. Anaerobiosis inhibited only partially the oxidation of MTR to formate, KMB/HMB, and methionine by avocado extract. The role of O 2 in the conversion of MTR to methionine is discussed

The functional cobalamin (vitamin B12)-intrinsic factor receptor is a novel complex of cubilin and amnionless

DEFF Research Database (Denmark)

Fyfe, John C; Madsen, Mette; Højrup, Peter

2004-01-01

Imerslund-Gräsbeck syndrome (I-GS, megaloblastic anemia 1) is an autosomal recessive disorder characterized by intestinal cobalamin (vitamin B(12)) malabsorption and proteinuria. I-GS-causing mutations are found in either of 2 genes encoding the epithelial proteins: cubilin and amnionless (AMN...... compartments. However, in cells cotransfected with AMN and the cubilin construct, cubilin trafficked to the cell surface and endosomes, and the cells exhibited IF-cobalamin endocytosis and lysosomal degradation of IF. These data indicate that cubilin and AMN are subunits of a novel cubilin/AMN (cubam) complex...

Effects of supplementary folic acid and vitamin B(12) on hepatic metabolism of dairy cows according to methionine supply.

Science.gov (United States)

Preynat, A; Lapierre, H; Thivierge, M C; Palin, M F; Cardinault, N; Matte, J J; Desrochers, A; Girard, C L

2010-05-01

The present experiment was undertaken to study the interactions between dietary supplements of rumen-protected methionine (RPM) and intramuscular injections of folic acid and vitamin B(12), given from 3 wk before calving to 16 wk of lactation, on hepatic metabolism of lactating dairy cows. Sixty multiparous Holstein cows were assigned to 10 blocks of 6 cows each according to their previous milk production. Within each block, 3 cows were fed a diet calculated to supply Met as 1.83% of metabolizable protein, whereas the 3 other cows were fed the same diet supplemented with 18g of RPM calculated to provide Met as 2.23% of metabolizable protein. Within each level of Met, the cows received no vitamin supplement or weekly intramuscular injections of 160mg of folic acid alone or combined with 10mg of vitamin B(12). Liver biopsies were taken at 2, 4, 8, and 16 wk of lactation. Liver concentrations of folates and vitamin B(12) were increased by their respective supplements but this response to vitamin supplements was altered by methionine supply. Concentrations of total lipids and triglycerides increased in livers of cows fed RPM, whereas concentrations of cholesterol ester, cholesterol, diglycerides, phosphatidylethanolamine, and phosphatidylcholine were not affected. Folic acid, alone or combined with vitamin B(12), tended to increase the ratio of phosphatidylcholine to phosphatidylethanolamine. Gene expression of 5,10-methylene-tetrahydrofolate reductase, microsomal transfer protein, and phosphatidylethanolamine methyltransferase were higher in liver of cows fed RPM supplements. The relative mRNA abundance of 5,10-methylene-tetrahydrofolate reductase and methylmalonyl-CoA mutase were increased by the combined injections of folic acid and vitamin B(12), whereas those of methionine synthase and methionine synthase reductase were not affected by treatments. These results suggest that increasing supply of methyl groups, as preformed labile methyl groups or through

Development of miniature module for [11C] methionine synthesis

International Nuclear Information System (INIS)

Watanabe, Toshimitsu; Araya, Hiroshi; Ueno, Satoshi

2006-01-01

[ 18 F]FDG-PET has spread rapidly in the cancer diagnosis. On the other hand, [ 11 C]Methionine is paid attention as one of the PET drugs that may help cancer diagnosis by [ 18 F]FDG. Due to its short half-life, repeated preparations of [ 11 C] Methionine, two or three times a day, are generally required for the routine PET practice. Although the automatic synthesis devices for [ 11 C]Methionine were developed, it was difficult to supply [ 11 C]Methionine two times a day or more. We developed a methionine synthesis system that was able to supply [ 11 C]Methionine two times a day or more, and a new methionine synthesis unit. The new synthesis unit is able to synthesize [ 11 C]Methionine efficiently without HPLC preparation and evaporation in a short time. The new methionine synthesis unit and system are more useful for the routine synthesis of [ 11 C]Methionine. (author)

Different Levels of Digestible Methionine on Performance of Broiler Starter

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WL Bryden

2010-01-01

Full Text Available Dietary protein and amino acid supply is the most expensive component of poultry diets. Therefore several efforts made by the industry to minimize the cost of the protein portion of the diet. Accordingly, there has been a recent move to use digestible amino acid values in the formulation of poultry diets. The efficiency of protein utilization depends to a large extent on the amino acid composition of the diet. The study was conducted to determine the digestible methionine requirement of broilers during the starter periods. One hundred and seventy five (175 chicks were allocated to 5 treatments with five replicates of seven chicks per replicate in a completely randomized design. Chicks were fed experimental diets from one day old to 21 days of age. Dietary treatments included 5 titrated levels each of digestible methionine (3.0, 4.5, 6.0, 7.5, and 9.0 g/kg diet added to a basal diet. The allowance of digestible methionine, rather than digestible sulphur amino acids was used in formulating the diets. Supplemental synthetic DL-Methionine which were considered to be 100% digestible were added to diets to obtain the concentration of the digestible amino acid. Each week until the conclusion of the trial, birds were individually weighed, feed intake per pen was measured, and feed conversion ratio (FCR was computed. This study suggested that the digestible methionine requirement for broiler starter is 4.7 g/kg for optimal body weight gain and 4.6 g/kg for optimal feed conversion ratio. (Animal Production 12(1: 6-11 (2010Key Words: amino acid, broiler, digestible, methionine, starter

Comparison of the rhizosphere bacterial communities of Zigongdongdou soybean and a high-methionine transgenic line of this cultivar.

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Jingang Liang

Full Text Available Previous studies have shown that methionine from root exudates affects the rhizosphere bacterial population involved in soil nitrogen fixation. A transgenic line of Zigongdongdou soybean cultivar (ZD91 that expresses Arabidopsis cystathionine γ-synthase resulting in an increased methionine production was examined for its influence to the rhizosphere bacterial population. Using 16S rRNA gene-based pyrosequencing analysis of the V4 region and DNA extracted from bacterial consortia collected from the rhizosphere of soybean plants grown in an agricultural field at the pod-setting stage, we characterized the populational structure of the bacterial community involved. In total, 87,267 sequences (approximately 10,908 per sample were analyzed. We found that Acidobacteria, Proteobacteria, Bacteroidetes, Actinobacteria, Chloroflexi, Planctomycetes, Gemmatimonadetes, Firmicutes, and Verrucomicrobia constitute the dominant taxonomic groups in either the ZD91 transgenic line or parental cultivar ZD, and that there was no statistically significant difference in the rhizosphere bacterial community structure between the two cultivars.

11C-methionine translocation in barley

International Nuclear Information System (INIS)

Nakanishi, Hiromi; Bughio, Naimatullah; Shigeta Ishioka, Noriko

2000-01-01

11 C-methionine was supplied to barley plants through a single leaf or via the roots and real time 11 C movement was monitored using a PETIS (positron emitting tracer imaging system). In Fe-deficient plants, 11 C-methionine was translocated from the tip of the absorbing leaf to the discrimination center' at the basal part of the shoot and then retranslocated to all the chlorotic leaves, while a negligible amount was retranslocated to the roots. In Fe-sufficient plants, methionine was translocated from the absorbing leaf to the discrimination center and then only to the newest leaf on the main shoot. A negligible amount was also retranslocated to the roots. Although, in Fe-sufficient plants, methionine translocation was observed from absorbing roots to shoots, in Fe-deficient plants, only a little amount was translocated from roots to shoots. In conclusion, methionine from the upper portion of a plant is not used as a precursor of mugineic acid under Fe-deficiency conditions. (author)

A U-shaped relationship between plasma folate and pancreatic cancer risk in the European Prospective Investigation into Cancer and Nutrition

NARCIS (Netherlands)

Chuang, Shu-Chun; Stolzenberg-Solomon, Rachael; Ueland, Per Magne; Vollset, Stein Emil; Midttun, Oivind; Olsen, Anja; Tjonneland, Anne; Overvad, Kim; Boutron-Ruault, Marie-Christine; Morois, Sophie; Clavel-Chapelon, Francoise; Teucher, Birgit; Kaaks, Rudolf; Weikert, Cornelia; Boeing, Heiner; Trichopoulou, Antonia; Benetou, Vassiliki; Naska, Androniki; Jenab, Mazda; Slimani, Nadia; Romieu, Isabelle; Michaud, Dominique S.; Palli, Domenico; Sieri, Sabina; Panico, Salvatore; Sacerdote, Carlotta; Tumino, Rosario; Skeie, Guri; Duell, Eric J.; Rodriguez, Laudina; Molina-Montes, Esther; Maria Huerta, Jose; Larranaga, Nerea; Barricarte Gurrea, Aurelio; Johansen, Dorthe; Manjer, Jonas; Ye, Weimin; Sund, Malin; Peeters, Petra H. M.; Jeurnink, Suzanne; Wareham, Nicholas; Khaw, Kay-Tee; Crowe, Francesca; Riboli, Elio; Bueno-de-Mesquita, Bas; Vineis, Paolo

Folate intake has shown an inverse association with pancreatic cancer; nevertheless, results from plasma measurements were inconsistent. The aim of this study is to examine the association between plasma total homocysteine, methionine, folate, cobalamin, pyridoxal 5'-phosphate, riboflavin, flavin

Methionine kinetics in adult men: effects of dietary betaine on L-[2H3-methyl-1-13C]methionine

International Nuclear Information System (INIS)

Storch, K.J.; Wagner, D.A.; Young, V.R.

1991-01-01

The effects of a daily 3-g supplement of betaine on kinetic aspects of L-[2H3-methyl-1-13C]methionine (MET) metabolism in healthy young adult men were explored. Four groups of four subjects each were given a control diet, based on an L-amino acid mixture supplying 29.5 and 21.9 mg.kg-1.d-1 of L-methionine and L-cystine for 4 d before the tracer study, conducted on day 5 during the fed state. Two groups received the control diet and two groups received the betaine supplement. Tracer was given intravenously (iv) or orally. The transmethylation rate of MET (TM), homocysteine remethylation (RM), and oxidation of methionine were estimated from plasma methionine labeling and 13C enrichment of expired air. RM tended to increase (P = 0.14) but the TM and methionine oxidation were significantly (P less than 0.05) higher after betaine supplementation when estimated with the oral tracer. No differences were detected with the intravenous tracer. Methionine concentration in plasma obtained from blood taken from subjects in the fed state was higher (P less than 0.01) with betaine supplementation. These results suggest that excess methyl-group intake may increase the dietary requirement for methionine

Methionine sulphoxide reductases revisited: free methionine as a primary target of H2O2 stress in auxotrophic fission yeast

OpenAIRE

García Santamarina, Sarela, 1978-; Boronat i Llop, Susanna, 1965-; Ayté del Olmo, José; Hidalgo Hernando, Elena

2013-01-01

Amino acid methionine can suffer reversible oxidation to sulphoxide and further irreversible over-oxidation to methionine sulphone. As part of the cellular antioxidant scavenging activities are the methionine sulphoxide reductases (Msrs), with a reported role in methionine sulphoxide reduction, both free and in proteins. Three families of Msrs have been described, but the fission yeast genome only includes one representative for two of these families: MsrA/Mxr1 and MsrB/Mxr2. We have investig...

Influence of folic acid, pyridoxal phosphate and cobalamin on plasma homocyst(e)ine levels and the susceptibility of low-density lipoprotein to ex-vivo oxidation.

Science.gov (United States)

Weiss, N; Feussner, A; Hailer, S; Spengel, F A; Keller, C; Wolfram, G

1999-10-15

Mild hyperhomocyst(e)inaemia is a risk factor for atherosclerotic vascular disease. In-vitro studies have shown that autooxidation of homocyst(e)ine is accompanied by the generation of oxygen radicals. This may lead to oxidative modification of low-density lipoproteins (LDL) and promote atherosclerotic vascular lesions. In male patients with peripheral arterial occlusive disease we determined fasting and post methionine load homocyst(e)ine levels by high performance liquid chromatography and the susceptibility of their LDL particles to ex-vivo oxidation by continously measuring the conjugated diene production induced by incubation with copper ions. Oxidation resistance (expressed as lag time), maximal oxidation rate, and extent of oxidation (expressed of total diene production) of LDL from patients with normal or mildly elevated homocyst(e)ine levels did not differ significantly. Folic acid, pyridoxal phosphate and cobalamin supplementation significantly decreased plasma homocyst(e)ine levels in hyperhomocyst(e)inaemic patients. This went along with a significant decrease in the extent of LDL oxidation and additionally increased HDL-cholesterol levels. The clinical relevance of these findings for the long-term course of atherosclerotic vascular disorders has to be determined by intervention studies.

A kinetic and mechanistic study on the oxidation of l-methionine and N-acetyl l-methionine by cerium(IV in sulfuric acid medium

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T. Sumathi

2016-09-01

Full Text Available The kinetics of oxidation of l-methionine and N-acetyl l-methionine by Ce(IV in sulfuric acid–sulfate media in the range of 288.1–298.1 K has been investigated. The major oxidation products of methionine and N-acetyl l-methionine have been identified as methionine sulfoxide and N-acetyl methionine sulfoxide. The major oxidation products have been confirmed by qualitative analysis and boiling point. The reaction was first order with respect to l-methionine, N-acetyl l-methionine and Ce(IV. Increase in [H+], ionic strength and HSO4- did not affect the reaction rate. Under the experimental conditions, Ce4+ was the effective oxidizing species of cerium. Increase in dielectric constant of the medium decreased the reaction rate. Under nitrogen atmosphere, the reaction system can initiate polymerization of acrylonitrile, indicating the generation of free radicals. Activation parameters associated with the overall reaction have been calculated.

A Protein Extract from Chicken Reduces Plasma Homocysteine in Rats

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Vegard Lysne

2015-06-01

Full Text Available The present study aimed to evaluate effects of a water-soluble protein fraction of chicken (CP, with a low methionine/glycine ratio, on plasma homocysteine and metabolites related to homocysteine metabolism. Male Wistar rats were fed either a control diet with 20% w/w casein as the protein source, or an experimental diet where 6, 14 or 20% w/w of the casein was replaced with the same amount of CP for four weeks. Rats fed CP had reduced plasma total homocysteine level and markedly increased levels of the choline pathway metabolites betaine, dimethylglycine, sarcosine, glycine and serine, as well as the transsulfuration pathway metabolites cystathionine and cysteine. Hepatic mRNA level of enzymes involved in homocysteine remethylation, methionine synthase and betaine-homocysteine S-methyltransferase, were unchanged, whereas cystathionine gamma-lyase of the transsulfuration pathway was increased in the CP treated rats. Plasma concentrations of vitamin B2, folate, cobalamin, and the B-6 catabolite pyridoxic acid were increased in the 20% CP-treated rats. In conclusion, the CP diet was associated with lower plasma homocysteine concentration and higher levels of serine, choline oxidation and transsulfuration metabolites compared to a casein diet. The status of related B-vitamins was also affected by CP.

Betaine is as effective as folate at re-synthesizing methionine for protein synthesis during moderate methionine deficiency in piglets.

Science.gov (United States)

McBreairty, Laura E; Robinson, Jason L; Harding, Scott V; Randell, Edward W; Brunton, Janet A; Bertolo, Robert F

2016-12-01

Both folate and betaine (synthesized from choline) are nutrients used to methylate homocysteine to reform the amino acid methionine following donation of its methyl group; however, it is unclear whether both remethylation pathways are of equal importance during the neonatal period when remethylation rates are high. Methionine is an indispensable amino acid that is in high demand in neonates not only for protein synthesis, but is also particularly important for transmethylation reactions, such as creatine and phosphatidylcholine synthesis. The objective of this study was to determine whether supplementation with folate, betaine, or a combination of both can equally re-synthesize methionine for protein synthesis when dietary methionine is limiting. Piglets were fed a low methionine diet devoid of folate, choline, and betaine, and on day 6, piglets were supplemented with either folate, betaine, or folate + betaine (n = 6 per treatment) until day 10. [1- 13 C]-phenylalanine oxidation was measured as an indicator of methionine availability for protein synthesis both before and after 2 days of supplementation. Prior to supplementation, piglets had lower concentrations of plasma folate, betaine, and choline compared to baseline with no change in homocysteine. Post-supplementation, phenylalanine oxidation levels were 20-46 % lower with any methyl donor supplementation (P = 0.006) with no difference among different supplementation groups. Furthermore, both methyl donors led to similarly lower concentrations of homocysteine following supplementation (P folate to remethylate methionine for protein synthesis, as indicated by lower phenylalanine oxidation.

Metabolic Regulation of Methionine Restriction in Diabetes.

Science.gov (United States)

Yin, Jie; Ren, Wenkai; Chen, Shuai; Li, Yuying; Han, Hui; Gao, Jing; Liu, Gang; Wu, Xin; Li, Tiejun; Kim, Sung Woo; Yin, Yulong

2018-03-30

Although the effects of dietary methionine restriction have been investigated in the physiology of aging and diseases related to oxidative stress, the relationship between methionine restriction and the development of metabolic disorders has not been explored extensively. This review summarizes studies of the possible involvement of dietary methionine restriction in improving insulin resistance, glucose homeostasis, oxidative stress, lipid metabolism, the pentose phosphate pathway, and inflammation, with an emphasis on the fibroblast growth factor 21 and protein phosphatase 2A signals and autophagy in diabetes. Diets deficient in methionine may be a useful nutritional strategy in patients with diabetes. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Pernicious Anemia Associated Cobalamin Deficiency and Thrombotic Microangiopathy: Case Report and Review of the Literature

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Farhanah Yousaf

2017-01-01

Full Text Available A 43-year-old Hispanic male without significant previous medical history was brought to emergency department for syncope following a blood draw to investigate a 40 lbs weight loss during the past 6 months associated with decreased appetite and progressive fatigue. The patient also reported a 1-month history of jaundice. On examination, he was hemodynamically stable and afebrile with pallor and diffuse jaundice but without skin rash or palpable purpura. Normal sensations and power in all extremities were evident on neurological exam. Presence of hemolytic anemia, schistocytosis, thrombocytopenia, and elevated lactate dehydrogenase (LDH was suggestive of thrombotic thrombocytopenic purpura (TTP. However, presence of leukopenia, macrocytes, and an inadequate reticulocyte response to the degree of anemia served as initial clues to an alternative diagnosis. Two and one units of packed red blood cells were transfused on day 1 and day 3, respectively. In addition, one unit of platelets was transfused on day 2. Daily therapeutic plasma exchange (TPE was initiated and continued until ADAMTS-13 result ruled out TTP. A low cobalamin (vitamin B12 level was evident at initial laboratory work-up and subsequent testing revealed positive intrinsic factor-blocking antibodies supporting a diagnosis of pernicious anemia with severe cobalamin deficiency. Hematological improvement was observed following vitamin B12 supplementation. The patient was discharged and markedly improved on day 9 with outpatient follow-up for cobalamin supplementation.

Quantitative proteomics reveals the mechanism and consequence of gliotoxin-mediated dysregulation of the methionine cycle in Aspergillus niger.

Science.gov (United States)

Manzanares-Miralles, Lara; Sarikaya-Bayram, Özlem; Smith, Elizabeth B; Dolan, Stephen K; Bayram, Özgür; Jones, Gary W; Doyle, Sean

2016-01-10

Gliotoxin (GT) is a redox-active metabolite, produced by Aspergillus fumigatus, which inhibits the growth of other fungi. Here we demonstrate how Aspergillus niger responds to GT exposure. Quantitative proteomics revealed that GT dysregulated the abundance of 378 proteins including those involved in methionine metabolism and induced de novo abundance of two S-adenosylmethionine (SAM)-dependent methyltransferases. Increased abundance of enzymes S-adenosylhomocysteinase (p=0.0018) required for homocysteine generation from S-adenosylhomocysteine (SAH), and spermidine synthase (p=0.0068), involved in the recycling of Met, was observed. Analysis of Met-related metabolites revealed significant increases in the levels of Met and adenosine, in correlation with proteomic data. Methyltransferase MT-II is responsible for bisthiobis(methylthio)gliotoxin (BmGT) formation, deletion of MT-II abolished BmGT formation and led to increased GT sensitivity in A. niger. Proteomic analysis also revealed that GT exposure also significantly (pniger. Thus, it provides new opportunities to exploit the response of GT-naïve fungi to GT. Copyright © 2015 Elsevier B.V. All rights reserved.

Genetic Polymorphism of Folate and Methionine Metabolizing Enzymes and their Susceptibility to Malignant Lymphoma

International Nuclear Information System (INIS)

Habib, E.E.; Aziz, M.; Kotb, M.

2005-01-01

Folate and methionine metabolism is involved in DNA synthesis and methylation. Polymorphisms in the genes of folate metabolism enzymes have been associated with some forms of cancer. In the present study, 2 polymorphisms were evaluated for a folate metabolic enzyme, methylene-tetrahydrofolate reductase (MTHFR), and one was evaluated for methionine synthase (MS). The 2 polymorphisms MTHFR 677 C-7T and MTHFR 1298 A-7C, are reported to reduce the enzyme activity, which causes intracellular accumulation of 5, 10 vm ethylene-tetrahydrofolate and results in a reduced incidence of DNA double strand breakage. The MS 2756 A-7G polymorphism also reduces the enzyme activity and results in the hypo methylation of DNA. Patients and Methods: To test this hypothesis, genetic polymorphisms in the folate metabolic pathway were investigated using the DNA from a case-control study on 31 patients having malignant lymphoma from the Oncology Outpatient Clinic of the New Children's Hospital, Cairo University and 30 controls who were actually normal children attending for vaccination to the same hospital. We found that there is a higher susceptibility with the MTHFR 677CC and MTHFR 1298 AA genotypes (OR=4.3, 95% CI 1.12-16). When those harbor at least one variant allele in either polymorphism of MTHFR they were defined as reference. For the MS 2756 AG genotype polymorphism there was also a higher susceptibility to developing malignant lymphoma (OR=2.6; 95% CI 1.16.4). Results suggest that folate and methionine metabolism may play an important role in the pathogenesis of malignant lymphoma. Further studies to confirm this association and detailed biologic mechanisms are now required

Effect of intramuscular injection of butafosfan and cobalamin on the quality of Fresh and Cooled Stallion Semen

Directory of Open Access Journals (Sweden)

Nicolás Cazales Penino

2015-08-01

Full Text Available The use of butafosfan in combination with cobalamin modulates many cellular metabolic functions in several species. Its use enhances productive and reproductive performance and reduces stress responses in animals. Despite all these attributes, so far there have been no controlled studies to evaluate the effects of butafosfan and cobalamin on the quality of stallion semen. The purpose of this study was to evaluate the action of butafosfan in combination with cobalamin on the quality of fresh and cooled stallion semen. Four healthy stallions were kept in the same place and under the same management conditions during the entire experiment. Stallions were randomly assigned to two treatment groups in a 2x2 crossover design. Group A stallions were treated with an intramuscular injection of butafosfan twice a week for 80 days, while group B did not receive any treatment. After that, both groups were not treated for another 80 days allowing a washout period for the treated group. Then, the groups were reversed, and group B was treated with butafosfan and group A acted as the control for another 80 days. Semen was collected twice a week, diluted in skim milk and evaluated for total sperm count, total and progressive sperm motility, membrane integrity (CFDA/PI staining and membrane functionality (HOS test at 0 and 24 hours after preservation at 5ºC. Data were analyzed by comparing the values obtained from the treated stallions between the 60th and 84th days of treatment and the values obtained from the same stallion during the control period. The ejaculates of the washout period and between days 1 and 63 of treatment were not considered. A total of 85 ejaculates were analyzed by one-way ANOVA. Means were compared by the Tukey test at the 5% level of significance. No significant differences were observed in fresh and cooled semen regarding the total sperm count, total motility, progressive motility, membrane integrity and membrane functionality in the

The biomarker-based validity of a food frequency questionnaire to assess the intake status of folate, pyridoxine and cobalamin among Iranian primary breast cancer patients.

Science.gov (United States)

Pirouzpanah, S; Taleban, F-A; Mehdipour, P; Atri, M; Hooshyareh-rad, A; Sabour, S

2014-03-01

Folate, pyridoxine and cobalamin are coenzymatically essential in one-carbon methyl metabolism, and their deficiencies could explain some alterations during breast carcinogenesis. We aimed to evaluate the validity of folate, pyridoxine and cobalamin estimates from a food frequency questionnaire (FFQ) on the basis of their corresponding fasting plasma biomarkers, in breast cancer (BC) patients. In a prospective, consecutive case series, 149 women with primary BC aged between 30 and 69 years as a representative sample of Iranian women with BC were recruited. The 136-item FFQ was used for the validity assay. Fasting plasma folate and cobalamin were tested by automated electrochemiluminescence. The high-pressure liquid chromatography with fluorescence detection was used to determine the plasma levels of pyridoxal-5'-phosphate (PLP) and total homocysteine (tHcy). Area under the curve (AUC) for assessing the diagnostic accuracy of folate-related data through an FFQ was 0.74 (Pfasting plasma concentrations. Our data supported the validity of new FFQ to rank individuals by dietary intake status of folate and cobalamin.

Methionine salvage pathway in relation to ethylene biosynthesis

International Nuclear Information System (INIS)

Miyazaki, J.H.

1987-01-01

The recycling of methionine during ethylene biosynthesis (the methionine cycle) was studied. During ethylene biosynthesis, the H 3 CS-group of S-adenosylmethionine (SAM) is released at 5'-methylthioadenosine (MTA), which is recycled to methionine via 5'-methylthioribose (MTS). In mungbean hypocotyls and cell-free extracts of avocado fruit, [ 14 C]MTR was converted to labeled methionine via 2-keto-4-methylthiobutyric acid (KMB) and 2-hydroxy-4-methylthiobutyric acid (HMB) as intermediates. Radioactive tracer studies showed that KMB was converted readily in vivo and in vitro to methionine, while HMB was converted much more slowly. The conversion of KMB to methionine by dialyzed avocado extract required an amino group donor. Among several potential donors tested, L-glutamine was the most efficient. Incubation of [ribose-U- 14 C]MTR with avocado extract resulted in the production of [ 14 C]formate, with little evolution of other 14 C-labeled one-carbon compounds, indicating that the conversion of MTR to KMB involves a loss of formate, presumably from C-1 of MTR

Purification of 1-aminocyclopropane-1-carboxylate synthase from apple fruits using s-adenosyl [3,414C]-methionine (SAM) as a probe

International Nuclear Information System (INIS)

Yip, Wingkip; Dong, Jianguo; Yang, Shang Fa

1989-01-01

Tomato ACC synthase is inactivated by its substrate SAM, with the moiety of aminobutyrate being covalently linked to ACC synthase during the catalytic reactions. A partial purified ACC synthase (the catalytic activity 100 μmol/h·mg protein) from pellets of apple extract was incubated with [3,4 14 C] SAM. Only one radioactive peak was revealed in a C-4 reverse phase HPLC and one radioactive band on SDS-PAGE with an M.W. of 48 kDa. Apple ACC synthase in native form is resistant to V8, α-chromtrypsin and carboxylpeptidase A digestion, but effectively inactivated by trypsin and ficin, as demonstrated by both the activity assay and SAM labeling. The radioactive protein cut from the SDS-PAGE was injected to three mice, two of the mice showed responses to the protein in western blot analysis. The antibodies from mice is currently under characterization

Stereochemical course of enzyme-catalyzed aminopropyl transfer: spermidine synthase

International Nuclear Information System (INIS)

Kullberg, D.W.; Orr, G.R.; Coward, J.K.

1986-01-01

The R and S enantionmers of S-adenosyl-3-[ 2 H]3-(methylthio)-1-propylamine (decarboxylated S-adenosylmethionine), previously synthesized in this laboratory, were incubated with [1,4- 2 H 4 ]-putrescine in the presence of spermidine synthase from E. coli. The resulting chiral [ 2 H 5 ]spermidines were isolated and converted to their N 1 ,N 7 -dibocspermidine-N 4 -(1S,4R)-camphanamides. The derivatives were analyzed by 500 MHz 1 H-NMR and the configuration of the chiral center assigned by correlation with the spectra of synthetic chiral [ 2 H 3 ]dibocspermidine camphanamide standards. The enzyme-catalyzed aminopropyl transfer was shown to occur with net retention of configuration, indicative of a double-displacement mechanism. This result concurs with that of a previous steady-state kinetics study of spermidine synthase isolated from E. coli, but contradicts the single-displacement mechanism suggested by a stereochemical analysis of chiral spermidines biosynthesized in E. coli treated with chirally deuterated methionines. It also indicates that this aminopropyltransferase is mechanistically distinct from the methyltransferases, which have been shown to act via a single-displacement mechanism (net inversion at -CH 3 ) in all cases studied to date

Composite organization of the cobalamin binding and cubilin recognition sites of intrinsic factor

DEFF Research Database (Denmark)

Fedosov, Sergey N; Fedosova, Natalya U; Berglund, Lars

2005-01-01

Intrinsic factor (IF(50)) is a cobalamin (Cbl)-transporting protein of 50 kDa, which can be cleaved into two fragments: the 30 kDa N-terminal peptide IF(30) and the 20 kDa C-terminal glycopeptide IF(20). Experiments on binding of Cbl to IF(30), IF(20), and IF(50) revealed comparable association r...

Homocysteine threshold value based on cystathionine beta synthase and paraoxonase 1 activities in mice.

Science.gov (United States)

Hamelet, J; Aït-Yahya-Graison, E; Matulewicz, E; Noll, C; Badel-Chagnon, A; Camproux, A-C; Demuth, K; Paul, J-L; Delabar, J M; Janel, N

2007-12-01

Hyperhomocysteinaemia is a metabolic disorder associated with the development of premature atherosclerosis. Among the determinants which predispose to premature thromboembolic and atherothrombotic events, serum activity of paraoxonase 1, mainly synthesized in the liver, has been shown to be a predictor of cardiovascular disease and to be negatively correlated with serum homocysteine levels in human. Even though treatments of hyperhomocysteinaemic patients ongoing cardiovascular complications are commonly used, it still remains unclear above which homocysteine level a preventive therapy should be started. In order to establish a threshold of plasma homocysteine concentration we have analyzed the hepatic cystathionine beta synthase and paraoxonase 1 activities in a moderate to intermediate murine model of hyperhomocysteinaemia. Using wild type and heterozygous cystathionine beta synthase deficient mice fed a methionine enriched diet or a control diet, we first studied the link between cystathionine beta synthase and paraoxonase 1 activities and plasma homocysteine concentration. Among the animals used in this study, we observed a negative correlation between plasma homocysteine level and cystathionine beta synthase activity (rho=-0.52, P=0.0008) or paraoxonase 1 activity (rho=-0.49, P=0.002). Starting from these results, a homocysteine cut-off value of 15 microm has been found for both cystathionine beta synthase (P=0.0003) and paraoxonase 1 (P=0.0007) activities. Our results suggest that both cystathionine beta synthase and paraoxonase 1 activities are significantly decreased in mice with a plasma homocysteine value greater than 15 microm. In an attempt to set up preventive treatment for cardiovascular disease our results indicate that treatments should be started from 15 microm of plasma homocysteine.

Nitrite reductase activity and inhibition of H₂S biogenesis by human cystathionine ß-synthase.

Directory of Open Access Journals (Sweden)

Carmen Gherasim

Full Text Available Nitrite was recognized as a potent vasodilator >130 years and has more recently emerged as an endogenous signaling molecule and modulator of gene expression. Understanding the molecular mechanisms that regulate nitrite metabolism is essential for its use as a potential diagnostic marker as well as therapeutic agent for cardiovascular diseases. In this study, we have identified human cystathionine ß-synthase (CBS as a new player in nitrite reduction with implications for the nitrite-dependent control of H₂S production. This novel activity of CBS exploits the catalytic property of its unusual heme cofactor to reduce nitrite and generate NO. Evidence for the possible physiological relevance of this reaction is provided by the formation of ferrous-nitrosyl (Fe(II-NO CBS in the presence of NADPH, the human diflavin methionine synthase reductase (MSR and nitrite. Formation of Fe(II-NO CBS via its nitrite reductase activity inhibits CBS, providing an avenue for regulating biogenesis of H₂S and cysteine, the limiting reagent for synthesis of glutathione, a major antioxidant. Our results also suggest a possible role for CBS in intracellular NO biogenesis particularly under hypoxic conditions. The participation of a regulatory heme cofactor in CBS in nitrite reduction is unexpected and expands the repertoire of proteins that can liberate NO from the intracellular nitrite pool. Our results reveal a potential molecular mechanism for cross-talk between nitrite, NO and H₂S biology.

21 CFR 172.399 - Zinc methionine sulfate.

Science.gov (United States)

2010-04-01

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.399 Zinc methionine sulfate. Zinc methionine...

Mutations in THAP11 cause an inborn error of cobalamin metabolism and developmental abnormalities.

Science.gov (United States)

Quintana, Anita M; Yu, Hung-Chun; Brebner, Alison; Pupavac, Mihaela; Geiger, Elizabeth A; Watson, Abigail; Castro, Victoria L; Cheung, Warren; Chen, Shu-Huang; Watkins, David; Pastinen, Tomi; Skovby, Flemming; Appel, Bruce; Rosenblatt, David S; Shaikh, Tamim H

2017-08-01

CblX (MIM309541) is an X-linked recessive disorder characterized by defects in cobalamin (vitamin B12) metabolism and other developmental defects. Mutations in HCFC1, a transcriptional co-regulator which interacts with multiple transcription factors, have been associated with cblX. HCFC1 regulates cobalamin metabolism via the regulation of MMACHC expression through its interaction with THAP11, a THAP domain-containing transcription factor. The HCFC1/THAP11 complex potentially regulates genes involved in diverse cellular functions including cell cycle, proliferation, and transcription. Thus, it is likely that mutation of THAP11 also results in biochemical and other phenotypes similar to those observed in patients with cblX. We report a patient who presented with clinical and biochemical phenotypic features that overlap cblX, but who does not have any mutations in either MMACHC or HCFC1. We sequenced THAP11 by Sanger sequencing and discovered a potentially pathogenic, homozygous variant, c.240C > G (p.Phe80Leu). Functional analysis in the developing zebrafish embryo demonstrated that both THAP11 and HCFC1 regulate the proliferation and differentiation of neural precursors, suggesting important roles in normal brain development. The loss of THAP11 in zebrafish embryos results in craniofacial abnormalities including the complete loss of Meckel's cartilage, the ceratohyal, and all of the ceratobranchial cartilages. These data are consistent with our previous work that demonstrated a role for HCFC1 in vertebrate craniofacial development. High throughput RNA-sequencing analysis reveals several overlapping gene targets of HCFC1 and THAP11. Thus, both HCFC1 and THAP11 play important roles in the regulation of cobalamin metabolism as well as other pathways involved in early vertebrate development. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Protein kinase Cα phosphorylates a novel argininosuccinate synthase site at serine 328 during calcium-dependent stimulation of endothelial nitric-oxide synthase in vascular endothelial cells.

Science.gov (United States)

Haines, Ricci J; Corbin, Karen D; Pendleton, Laura C; Eichler, Duane C

2012-07-27

Endothelial nitric-oxide synthase (eNOS) utilizes l-arginine as its principal substrate, converting it to l-citrulline and nitric oxide (NO). l-Citrulline is recycled to l-arginine by two enzymes, argininosuccinate synthase (AS) and argininosuccinate lyase, providing the substrate arginine for eNOS and NO production in endothelial cells. Together, these three enzymes, eNOS, AS, and argininosuccinate lyase, make up the citrulline-NO cycle. Although AS catalyzes the rate-limiting step in NO production, little is known about the regulation of AS in endothelial cells beyond the level of transcription. In this study, we showed that AS Ser-328 phosphorylation was coordinately regulated with eNOS Ser-1179 phosphorylation when bovine aortic endothelial cells were stimulated by either a calcium ionophore or thapsigargin to produce NO. Furthermore, using in vitro kinase assay, kinase inhibition studies, as well as protein kinase Cα (PKCα) knockdown experiments, we demonstrate that the calcium-dependent phosphorylation of AS Ser-328 is mediated by PKCα. Collectively, these findings suggest that phosphorylation of AS at Ser-328 is regulated in accordance with the calcium-dependent regulation of eNOS under conditions that promote NO production and are in keeping with the rate-limiting role of AS in the citrulline-NO cycle of vascular endothelial cells.

A simple radioactivity assay for measurement of methionine adenosyltransferase activity by aqueous chromatography

International Nuclear Information System (INIS)

Oeztuerk, M.; Lemonnier, F.; Cresteil, D.; Lemonnier, A.

1983-01-01

Methionine adenosyltransferase (ATP:L-methionine S-adenosyltransferase, EC 2.5.1.6) catalyzes the formation of S-adenosyl-L-methionine from ATP and L-methionine. Methionine metabolism is very important in human pathology. Methionine adenosyltransferase deficiency has recently been shown to be a specific enzymatic defect, whereas certain other diseases have only been associated with non-specific deficiencies of methionine adenosyltransferase. These different reasons explain the existence of numerous reports concerning the determination of hepatic methionine adenosyltransferase and of its isozymic forms, found in different tissues in man and rat. On the basis of the work of Chou and Lombardini, the authors report a rapid, sensitive technique using aqueous chromatography with phosphocellulose ion exchange paper to separate the S-adenosyl L-[methyl- 14 C]methionine from L-[methyl- 14 C]methionine. (Auth.)

Effects of transgenic methionine sulfoxide reductase A (MsrA expression on lifespan and age-dependent changes in metabolic function in mice

Directory of Open Access Journals (Sweden)

Adam B. Salmon

2016-12-01

Full Text Available Mechanisms that preserve and maintain the cellular proteome are associated with long life and healthy aging. Oxidative damage is a significant contributor to perturbation of proteostasis and is dealt with by the cell through regulation of antioxidants, protein degradation, and repair of oxidized amino acids. Methionine sulfoxide reductase A (MsrA repairs oxidation of free- and protein-bound methionine residues through enzymatic reduction and is found in both the cytosol and the mitochondria. Previous studies in Drosophila have shown that increasing expression of MsrA can extend longevity. Here we test the effects of increasing MsrA on longevity and healthy aging in two transgenic mouse models. We show that elevated expression of MsrA targeted specifically to the cytosol reduces the rate of age-related death in female mice when assessed by Gompertz analysis. However, neither cytosolic nor mitochondrial MsrA overexpression extends lifespan when measured by log-rank analysis. In mice with MsrA overexpression targeted to the mitochondria, we see evidence for improved insulin sensitivity in aged female mice. With these and our previous data, we conclude that the increasing MsrA expression in mice has differential effects on aging and healthy aging that are dependent on the target of its subcellular localization.

Absorption of food cobalamins assessed by the double isotope method in healthy volunteers and in patients with chronic diarrhoea

International Nuclear Information System (INIS)

Kittang, B.; Hamborg, B.; Schjoensby, H.

1985-01-01

To make a food preparation containing radioactively labelled cobalamins, rabbits were given repeated injections with 57 Co-labelled cyanocobalamin. The liver was removed, homogenized and fried for one min. or boiled for 30 min. Of the radioactivity in the fried homogenate, 41.7% was recovered in the centrifuged supernatant compared with 50.8% in the boiled homogenate. The radioactivity in the supernatants had a molecular size close to that of free 57 Co-labelled cyanocobalamin. 42% of the radioactivity in the whole homogenate had been incorporated into 5-deoxyadenosyl-, 10% into methyl-and 16.5% into hydroxy-cobalamin. To assess the validity of a double-isotope method for measuring the intestinal absorption of doses of 57 Co-labelled liver cobalamins, 51 CrCl 3 was used as a non-absorbable marker. In 14 healthy volunteers the correlation coefficient between the absorption measured by the double-isotope technique and the faecal excretion test was highly significant (r = 0.96, p 57 Co/ 51 Cr ratio in successive stool collections. In 11 patients with chronic diarrhoea there was a significant correlation between the absorption measured by the double-isotope technique and the faecal excretion test (r = 0.92, p 57 / 51 Cr ratio in successive stool collections

Methionine as a Precursor of Ethylene—Commentary

Science.gov (United States)

Lieberman et al. showed in a 1966 publication of Plant Physiology that methionine is a precursor of ethylene. It was the first paper that showed ethylene carbons are derived from carbons 3 and 4 of methionine. This paper catalyzed remarkable interest among plant biologists to elucidate the biosynth...

Molecular cloning and characterization of l-methionine γ-lyase from Streptomyces avermitilis.

Science.gov (United States)

Kudou, Daizou; Yasuda, Eri; Hirai, Yoshiyuki; Tamura, Takashi; Inagaki, Kenji

2015-10-01

A pyridoxal 5'-phosphate-dependent methionine γ-lyase (MGL) was cloned from Streptomyces avermitilis catalyzed the degradation of methionine to α-ketobutyrate, methanethiol, and ammonia. The sav7062 gene (1,242 bp) was corresponded to 413 amino acid residues with a molecular mass of 42,994 Da. The deduced amino acid sequence showed a high degree of similarity to those of other MGL enzymes. The sav7062 gene was overexpressed in Escherichia coli. The enzyme was purified to homogeneity and exhibited the MGL catalytic activities. We cloned the enzyme that has the MGL activity in Streptomyces for the first time. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Effects of Methionine Containing Paracetamol Formulation on ...

African Journals Online (AJOL)

Effects of Methionine Containing Paracetamol Formulation on Serum Vitamins and Trace Elements in Male Rats. AA Iyanda, JI Anetor, DP Oparinde, FAA Adeniyi. Abstract. Methionine is an effective antidote in the treatment of paracetamol-induced toxicity but at large doses it has been reported to induce or aggravate a ...

Optimization of L: -methionine feeding strategy for improving S-adenosyl-L: -methionine production by methionine adenosyltransferase overexpressed Pichia pastoris.

Science.gov (United States)

Hu, Hui; Qian, Jiangchao; Chu, Ju; Wang, Yonghong; Zhuang, Yingping; Zhang, Siliang

2009-07-01

The recombinant Pichia pastoris harboring an improved methionine adenosyltransferase (MAT) shuffled gene was employed to biosynthesize S-adenosyl-L: -methionine (SAM). Two L: -methionine (L: -Met) addition strategies were used to supply the precursor: the batch addition strategy (L: -Met was added separately at three time points) and the continuous feeding strategies (L: -Met was fed continuously at the rate of 0.1, 0.2, and 0.5 g l(-1) h(-1), respectively). SAM accumulation, L: -Met conversion rate, and SAM productivity with the continuous feeding strategies were all improved over the batch addition strategy, which reached 8.46 +/- 0.31 g l(-1), 41.7 +/- 1.4%, and 0.18 +/- 0.01 g l(-1) h(-1) with the best continuous feeding strategy (0.2 g l(-1) h(-1)), respectively. The bottleneck for SAM production with the low L: -Met feeding rate (0.1 g L(-1) h(-1)) was the insufficient L: -Met supply. The analysis of the key enzyme activities indicated that the tricarboxylic acid cycle and glycolytic pathway were reduced with the increasing L: -Met feeding rate, which decreased the adenosine triphosphate (ATP) synthesis. The MAT activity also decreased as the L: -Met feeding rate rose. The reduced ATP synthesis and MAT activity were probably the reason for the low SAM accumulation when the L: -Met feeding rate reached 0.5 g l(-1) h(-1).

A66G and C524T polymorphisms of methionine synthase reductase gene are linked to the development of acyanotic congenital heart diseases in Egyptian children.

Science.gov (United States)

Hassan, Fahima M; Khattab, Ahmad A; Abo El Fotoh, Wafaa Moustafa M; Zidan, Reham S

2017-09-20

Methionine synthase reductase (MTRR) is one of the main regulatory enzymes in the homocysteine/folate pathway. Genes involved in this pathway may play an important role in the development of congenital heart diseases (CHDs). C524T and A66G polymorphisms of MTRR gene may play an imperative role in the development of acyanotic CHDs. This study carried out on 200 children equally divided into 2 groups: group I: 100 children with acyanotic CHDs; and group II: 100 healthy children served as controls. PCR-RFLP method carried out to amplify the A66G and C524T polymorphisms of MTRR gene digested with Xho1and NdeI enzymes. A significant difference(P=0.015) in genotype frequencies of C524T polymorphism between cases and controls, where CC, CT, and TT were 14.0%, 40.0% and 46.0% in patients compared to 38.0,36.0% and 26.0% in controls. Again, a significant difference (P=0.010) in genotype frequencies of A66G polymorphism between the two groups as AA, AG and GG were 26.0%, 32.0% and42.0% in patients compared to 48.0, 36.0% and 16.0% in controls. Also, MTRR A66G and C524T polymorphisms were associated with a higher CHD risk in the homozygote comparison of wild and mutant genotypes and also in heterozygote and mutant comparison. So A66G and C524T polymorphisms of MTRR gene are associated with increased risk of acyanotic CHDs. Copyright © 2017 Elsevier B.V. All rights reserved.

Follicular thyroid cancer avid on C-11 Methionine PET/CT

OpenAIRE

Jochumsen, Mads Ryø; Iversen, Peter; Arveschoug, Anne Kirstine

2018-01-01

Summary A case of follicular thyroid cancer with intense focal Methionine uptake on 11C-Methionine PET/CT is reported here. The use of 11C-Methionine PET in differentiated thyroid cancer is currently being investigated as a surrogate tracer compared to the more widely used 18F-FDG PET. This case illustrates the potential incremental value of this modality, not only in the localizing of parathyroid adenoma, but also indicating that 11C-Methionine PET might have a potential of increasing the pr...

Transcellular transport of cobalamin in aortic endothelial cells.

Science.gov (United States)

Hannibal, Luciana; Bolisetty, Keerthana; Axhemi, Armend; DiBello, Patricia M; Quadros, Edward V; Fedosov, Sergey; Jacobsen, Donald W

2018-05-09

Cobalamin [Cbl (or B 12 )] deficiency causes megaloblastic anemia and a variety of neuropathies. However, homeostatic mechanisms of cyanocobalamin (CNCbl) and other Cbls by vascular endothelial cells are poorly understood. Herein, we describe our investigation into whether cultured bovine aortic endothelial cells (BAECs) perform transcytosis of B 12 , namely, the complex formed between serum transcobalamin and B 12 , designated as holo-transcobalamin (holo-TC). We show that cultured BAECs endocytose [ 57 Co]-CNCbl-TC (source material) via the CD320 receptor. The bound Cbl is transported across the cell both via exocytosis in its free form, [ 57 Co]-CNCbl, and via transcytosis as [ 57 Co]-CNCbl-TC. Transcellular mobilization of Cbl occurred in a bidirectional manner. A portion of the endocytosed [ 57 Co]-CNCbl was enzymatically processed by methylmalonic aciduria combined with homocystinuria type C (cblC) with subsequent formation of hydroxocobalamin, methylcobalamin, and adenosylcobalamin, which were also transported across the cell in a bidirectional manner. This demonstrates that transport mechanisms for Cbl in vascular endothelial cells do not discriminate between various β-axial ligands of the vitamin. Competition studies with apoprotein- and holo-TC and holo-intrinsic factor showed that only holo-TC was effective at inhibiting transcellular transport of Cbl. Incubation of BAECs with a blocking antibody against the extracellular domain of the CD320 receptor inhibited uptake and transcytosis by ∼40%. This study reveals that endothelial cells recycle uncommitted intracellular Cbl for downstream usage by other cell types and suggests that the endothelium is self-sufficient for the specific acquisition and subsequent distribution of circulating B 12 via the CD320 receptor. We posit that the endothelial lining of the vasculature is an essential component for the maintenance of serum-tissue homeostasis of B 12 .-Hannibal, L., Bolisetty, K., Axhemi, A., DiBello, P

Prediction of Methionine and Homocysteine levels in Zucker diabetic fatty (ZDF) rats as a T2DM animal model after consumption of a Methionine-rich diet

OpenAIRE

Han, Nayoung; Chae, Jung-woo; Jeon, Jihyun; Lee, Jaeyeon; Back, Hyun-moon; Song, Byungjeong; Kwon, Kwang-il; Kim, Sang Kyum; Yun, Hwi-yeol

2018-01-01

Background Although alterations in the methionine metabolism cycle (MMC) have been associated with vascular complications of diabetes, there have not been consistent results about the levels of methionine and homocysteine in type 2 diabetes mellitus (T2DM). The aim of the current study was to predict changes in plasma methionine and homocysteine concentrations after simulated consumption of methionine-rich foods, following the development of a mathematical model for MMC in Zucker Diabetic Fat...

Phosphorylation of inhibitor-2 and activation of MgATP-dependent protein phosphatase by rat skeletal muscle glycogen synthase kinase

International Nuclear Information System (INIS)

Hegazy, M.G.; Reimann, E.M.; Thysseril, T.J.; Schlender, K.K.

1986-01-01

Rat skeletal muscle contains a glycogen synthase kinase (GSK-M) which is not stimulated by Ca 2+ or cAMP. This kinase has an apparent Mr of 62,000 and uses ATP but not GTP as a phosphoryl donor. GSK-M phosphorylated glycogen synthase at sites 2 and 3. It phosphorylated ATP-citrate lyase and activated MgATP-dependent phosphatase in the presence of ATP but not GTP. As expected, the kinase also phosphorylated phosphatase inhibitor 2 (I-2). Phosphatase incorporation reached approximately 0.3 mol/mol of I-2. Phosphopeptide maps were obtained by digesting 32 P-labeled I-2 with trypsin and separating the peptides by reversed phase HPLC. Two partially separated 32 P-labeled peaks were obtained when I-2 was phosphorylated with either GSK-M or glycogen synthase kinase 3 (GSK-3) and these peptides were different from those obtained when I-2 was phosphorylated with the catalytic subunit of cAMP-dependent protein kinase (CSU) or casein kinase II (CK-II). When I-2 was phosphorylated with GSK-M or GSK-3 and cleaved by CNBr, a single radioactive peak was obtained. Phosphoamino acid analysis showed that I-2 was phosphorylated by GSK-M or GSK-3 predominately in Thr whereas CSU and CK-II phosphorylated I-2 exclusively in Ser. These results indicate that GSK-M is similar to GSK-3 and to ATP-citrate lyase kinase. However, it appears to differ in Mr from ATP-citrate lyase kinase and it differs from GSK-3 in that it phosphorylates glycogen synthase at site 2 and it does not use GTP as a phosphoryl donor

11C-methionine PET, a novel method for measuring regional salivary gland function after radiotherapy of head and neck cancer

International Nuclear Information System (INIS)

Buus, Simon; Grau, Cai; Munk, Ole Lajord; Bender, Dirk; Jensen, Kenneth; Keiding, Susanne

2004-01-01

Background and purpose: Loss of salivary gland function is a distressing side-effect of radiotherapy (RT) for head and neck cancer. The aim of this study was to develop a positron emission tomography (PET) method for measuring regional salivary gland function in the major salivary glands irradiated during RT. Patients and methods: Eight head and neck cancer patients were included; two were examined before RT and six after parotid sparing RT. Patients were examined by dynamic 11 C-methionine PET of the major salivary glands and parotid gland salivary flow measurements. PET data were analysed using a kinetic model of salivary gland 11 C-methionine metabolism, in which salivary gland function was quantified by the net metabolic clearance of 11 C-methionine, K. Functional voxel-wise images of K were calculated and matched with the CT-dose-plan for comparing regional salivary gland function with the regional radiation dose. Results: Parotid gland K correlated positively with parotid gland salivary flow, indicating that K can be used as an index of salivary gland function. K of parotid and submandibular glands was reduced dependent on the median radiation dose. In one patient, receiving a heterogeneous radiation dose to the parotid glands, regional salivary gland function was inversely correlated to the regional radiation dose. Conclusions: Salivary gland function can be measured by dynamic 11 C-methionine PET. The net metabolic clearance of 11 C-methionine of salivary glands was reduced dependent on the radiation dose. Dynamic 11 C-methionine PET offers a method for studying the individual response of the major salivary glands to irradiation

Reactions of cisplatin with cysteine and methionine at constant pH; a computational study.

Science.gov (United States)

Zimmermann, Tomás; Burda, Jaroslav V

2010-02-07

Interactions of hydrated cisplatin complexes cis-[Pt(NH(3))(2)Cl(H(2)O)](+) and cis-[Pt(NH(3))(2)(OH)(H(2)O)](+) with cysteine and methionine in an aqueous solution at constant pH were explored using computational methods. Thermodynamic parameters of considered reactions were studied in a broad pH range, taking up to 4 protonation states of each molecule into account. Reaction free energies at constant pH were obtained from standard Gibbs free energies using the Legendre transformation. Solvation free energies and pK(a) values were calculated using the PCM model with UAHF cavities, recently adapted by us for transition metal complexes. The root mean square error of pK(a) values on a set of model platinum complexes and amino acids was equal to 0.74. At pH 7, the transformed Gibbs free energies differ by up to 15 kcal mol(-1) from the Gibbs free energies of model reactions with a constant number of protons. As for cysteine, calculations confirmed a strong preference for kappaS monodenate bonding in a broad pH range. The most stable product of the second reaction step, which proceeds from monodentate to chelate complex, is the kappa(2)S,N coordinated chelate. The reaction with methionine is more complex. In the first step all three considered methionine donor atoms (N, S and O) are thermodynamically preferred products depending on the platinum complex and the pH. This is in accordance with the experimental observation of a pH dependent migration between N and S donor atoms in a chemically related system. The most stable chelates of platinum with methionine are kappa(2)S,N and kappa(2)N,O bonded complexes. The comparison of reaction free energies of both amino acids suggests, that the bidentate methionine ligand can be displaced even by the monodentate cysteine ligand under certain conditions.

Acute Administration of Methionine Affects Performance of Swiss ...

African Journals Online (AJOL)

Acetylcholinesterase activities in all groups were not statistically significant. It can be concluded that acute methionine administration has some benefits in memory enhancement. However, a short course folate supplementation impairslearning and working memory especially when combined with methionine which may be ...

Follicular thyroid cancer avid on C-11 Methionine PET/CT

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Mads Ryø Jochumsen

2018-01-01

Full Text Available A case of follicular thyroid cancer with intense focal Methionine uptake on 11C-Methionine PET/CT is reported here. The use of 11C-Methionine PET in differentiated thyroid cancer is currently being investigated as a surrogate tracer compared to the more widely used 18F-FDG PET. This case illustrates the potential incremental value of this modality, not only in the localizing of parathyroid adenoma, but also indicating that 11C-Methionine PET might have a potential of increasing the pretest likelihood of thyroid malignancy in a cold nodule with highly increased Sestamibi uptake.

Comparative efficacy of herbal and synthetic methionine on ...

African Journals Online (AJOL)

HM) compared to synthetic methionine (SM) in the diets of domestic laying hens. The herbal methionine (Meth-o-Tas®) was supplied by Intas Pharmaceutical Limited, India. The HM and SM were added to a standard diet at 0.5 and 1.0 kg per ...

Influence of dietary methionine on the metabolism of selenomethionine in rats

International Nuclear Information System (INIS)

Butler, J.A.; Beilstein, M.A.; Whanger, P.D.

1989-01-01

To determine the influence of methionine on selenomethionine (SeMet) metabolism, weanling male rats were fed for 8 wk a basal diet marginally deficient in sulfur amino acids, containing 2.0 micrograms selenium (Se)/g as DL-SeMet and supplemented with 0, 0.3, 0.6 or 1.2% DL-methionine. Increased dietary methionine caused decreased selenium deposition in all tissues examined but increased glutathione peroxidase activity in testes, liver and lungs. A positive correlation was found between dietary methionine and the calculated percentage of selenium associated with GSHPx. In a second experiment, 75 SeMet was injected into weanling male rats which had been fed the basal diet containing 2.0 micrograms selenium as DL-SeMet with or without the addition of 1.0% methionine. The selenoamino acid content of tissues and the distribution of 75 Se in erythrocyte proteins were determined. In comparison to the rats fed the basal diet without added methionine, significantly more 75 Se-selenocysteine was found in liver and muscle, more 75 Se was found in erythrocyte GSHPx and less 75 Se was found in erythrocyte hemoglobin of rats fed 1.0% methionine. These data suggest that methionine diverts SeMet from incorporation into general proteins and enhances its conversion to selenocysteine for specific selenium-requiring proteins, such as GSHPx

Traumatic brain injury alters methionine metabolism: implications for pathophysiology

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Pramod K Dash

2016-04-01

Full Text Available Methionine is an essential proteinogenic amino acid that is obtained from the diet. In addition to its requirement for protein biosynthesis, methionine is metabolized to generate metabolites that play key roles in a number of cellular functions. Metabolism of methionine via the transmethylation pathway generates S-adenosylmethionine (SAM that serves as the principal methyl (-CH3 donor for DNA and histone methyltransferases to regulate epigenetic changes in gene expression. SAM is also required for methylation of other cellular proteins that serve various functions and phosphatidylcholine synthesis that participate in cellular signaling.. Under conditions of oxidative stress, homocysteine (which is derived from SAM enters the transsulfuration pathway to generate glutathione, an important cytoprotective molecule against oxidative damage. As both experimental and clinical studies have shown that traumatic brain injury (TBI alters DNA and histone methylation and causes oxidative stress, we examined if TBI alters the plasma levels of methionine and its metabolites in human patients. Blood samples were collected from healthy volunteers (n = 20 and patients with mild TBI (GCS > 12; n = 20 or severe TBI (GCS < 8; n = 20 within the first 24 hours of injury. The levels of methionine and its metabolites in the plasma samples were analyzed by either liquid chromatography-mass spectrometry or gas chromatography-mass spectrometry (LC-MS or GC-MS. Severe TBI decreased the levels of methionine, SAM, betaine and 2-methylglycine as compared to healthy volunteers, indicating a decrease in metabolism through the transmethylation cycle. In addition, precursors for the generation of glutathione, cysteine and glycine were also found to be decreased as were intermediate metabolites of the gamma-glutamyl cycle (gamma-glutamyl amino acids and 5-oxoproline. Mild TBI also decreased the levels of methionine, α-ketobutyrate, 2 hydroxybutyrate and glycine, albeit to lesser

Isolation of L-methionine-enriched mutant of a methylotrophic yeast, Candida boidinii No.2201

International Nuclear Information System (INIS)

Tani, Y.; Lim, W.J.; Yang, H.C.

1988-01-01

Six strains of methylotrophic yeast were examined for production of L-methionine-enriched cells. Candida boidinii (kloeckera sp.) No. 2201,which accumulated 0.54 mg/g-dry cell weight (DCW) of free L-methionine (pool methionine), was selected as the parental strain for breeding L-methionine-rich mutants. Ethionine-resistant mutants were derived from the strain by UV irradiation. A mutant strain, E500-78,which was resistant to 500 μg/ml of DL-ethionine, accumulated 6.02 mg/g-DCW of pool methionine. The culture conditions for mutant strain E500-78 to increase pool methionine accumulation were optimized. As a result, the mutant strain accumulated 8.80 mg/g-DCW of pool methionine and contained 16.02 mg/g-DCW total methionine

Cobalamin deficiency, hyperhomocysteinemia, and dementia

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Steven F Werder

2010-04-01

Full Text Available Steven F Werder1,21Kansas University School of Medicine – Wichita, Wichita, KS, USA; 2Community Health Center of Southeast Kansas, Pittsburg, KS, USAIntroduction: Although consensus guidelines recommend checking serum B12 in patients with dementia, clinicians are often faced with various questions: (1 Which patients should be tested? (2 What test should be ordered? (3 How are inferences made from such testing? (4 In addition to serum B12, should other tests be ordered? (5 Is B12 deficiency compatible with dementia of the Alzheimer’s type? (6 What is to be expected from treatment? (7 How is B12 deficiency treated?Methods: On January 31st, 2009, a Medline search was performed revealing 1,627 citations related to cobalamin deficiency, hyperhomocysteinemia, and dementia. After limiting the search terms, all abstracts and/or articles and other references were categorized into six major groups (general, biochemistry, manifestations, associations and risks, evaluation, and treatment and then reviewed in answering the above questions.Results: The six major groups above are described in detail. Seventy-five key studies, series, and clinical trials were identified. Evidence-based suggestions for patient management were developed.Discussion: Evidence is convincing that hyperhomocysteinemia, with or without hypovitaminosis B12, is a risk factor for dementia. In the absence of hyperhomocysteinemia, evidence is less convincing that hypovitaminosis B12 is a risk factor for dementia. B12 deficiency manifestations are variable and include abnormal psychiatric, neurological, gastrointestinal, and hematological findings. Radiological images of individuals with hyperhomocysteinemia frequently demonstrate leukoaraiosis. Assessing serum B12 and treatment of B12 deficiency is crucial for those cases in which pernicious anemia is suspected and may be useful for mild cognitive impairment and mild to moderate dementia. The serum B12 level is the standard initial test

21 CFR 582.5477 - Methionine hydroxy analog and its calcium salts.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Methionine hydroxy analog and its calcium salts... Nutrients and/or Dietary Supplements 1 § 582.5477 Methionine hydroxy analog and its calcium salts. (a) Product. Methionine hydroxy analog and its calcium salts. (b) [Reserved] (c) Limitations, restrictions, or...

Induction of Alzheimer's-like changes in brain of mice expressing mutant APP fed excess methionine.

NARCIS (Netherlands)

McCampbell, A.; Wessner, K.; Marlatt, M.W.; Wolffe, C.; Toolan, D.; Podtelezhnikov, A.; Yeh, S.; Zhang, R.; Szcerba, P.; Tanis, K.Q.; Majercak, J.; Ray, W.J.; Savage, M.

2011-01-01

Elevated plasma homocysteine, a risk factor for Alzheimer's disease, could result from increased production from methionine or by inefficient clearance by folate- and B-vitamin-dependent pathways. Understanding the relative contributions of these processes to pathogenesis is important for

S-adenosyl-L-methionine for alcoholic liver diseases

DEFF Research Database (Denmark)

Rambaldi, A; Gluud, C

2006-01-01

Alcohol is a major cause of liver disease and disrupts methionine and oxidative balances. S-adenosyl-L-methionine (SAMe) acts as a methyl donor for methylation reactions and participates in the synthesis of glutathione, the main cellular antioxidant. Randomised clinical trials have addressed...... the question whether SAMe may benefit patients with alcoholic liver diseases....

Comparative proteomic analyses reveal the proteome response to short-term drought in Italian ryegrass (Lolium multiflorum.

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Ling Pan

Full Text Available Drought is a major abiotic stress that impairs growth and productivity of Italian ryegrass. Comparative analysis of drought responsive proteins will provide insight into molecular mechanism in Lolium multiflorum drought tolerance. Using the iTRAQ-based approach, proteomic changes in tolerant and susceptible lines were examined in response to drought condition. A total of 950 differentially accumulated proteins was found to be involved in carbohydrate metabolism, amino acid metabolism, biosynthesis of secondary metabolites, and signal transduction pathway, such as β-D-xylosidase, β-D-glucan glucohydrolase, glycerate dehydrogenase, Cobalamin-independent methionine synthase, glutamine synthetase 1a, Farnesyl pyrophosphate synthase, diacylglycerol, and inositol 1, 4, 5-trisphosphate, which might contributed to enhance drought tolerance or adaption in Lolium multiflorum. Interestingly, the two specific metabolic pathways, arachidonic acid and inositol phosphate metabolism including differentially accumulated proteins, were observed only in the tolerant lines. Cysteine protease cathepsin B, Cysteine proteinase, lipid transfer protein and Aquaporin were observed as drought-regulated proteins participating in hydrolysis and transmembrane transport. The activities of phospholipid hydroperoxide glutathione peroxidase, peroxiredoxin, dehydroascorbate reductase, peroxisomal ascorbate peroxidase and monodehydroascorbate reductase associated with alleviating the accumulation of reactive oxygen species in stress inducing environments. Our results showed that drought-responsive proteins were closely related to metabolic processes including signal transduction, antioxidant defenses, hydrolysis, and transmembrane transport.

Biosynthetic preparation of 35-S labelled methionine

International Nuclear Information System (INIS)

Freud, A.; Hirshfeld, N.; Teitelbaum, Z.; Heimer, Y.

1986-11-01

High specific activity methionine with sulfur-35 was prepared in our laboratory by growing Baker's yeast cells, in a medium containing 35 S-sulfate. L-S 35 methionine was prepared from the acid hydrolyzate of the proteins by chromatography on whatman paper. The specific activity was determined using o-phtaladehyde as a fluorophore to form a fluorescent complex. The specific activity was found to be usually greater than 800 Ci/mmol. (Author)

The effects of an L-methionine combination supplement on ...

African Journals Online (AJOL)

Interventions. L-methionine combination supplement (L-methionine, vitamin B6, vitamin B12, folic acid and magnesium) or placebo containing potato starch. Main outcome measures. Incidence of URTS was recorded during the runner's preparation for an ultramarathon race (75 days) and recovery from the same (75 days).

Oxidation of methionine in PrP is dependent upon the oxidant and the amino acid two positions removed

Science.gov (United States)

Background/Introduction. Methionine oxidation has been shown both to be associated with prion formation and implicated in the inhibition of amyloid formation in model systems. This work is based on model systems where hydrogen peroxide was used as an oxidant. Materials and Methods. We developed...

Utilization of 35S methionine by the goat

International Nuclear Information System (INIS)

Champredon, C.; Pion, R.

1977-01-01

A mixture of 2.5 g of D,L-methionine and 2.1 mCi of L- 35 S methionine is injected into the rumen of two young dry goats. Abomasal contents and blood are sampled for 4 days after intraruminal injection of the tracer. Total radioactivity and specific activity of sulfur amino acids are measured in free- and protein-bound fractions of abomasal contents and blood. The radioactivity of the abomasal content soluble fraction (TCA) increases very rapidly. The main labelled compound in the TCA extract during the first hour is methionine. Total plasma radioactivity increases during the 9 hours following the injection, then decreases slowly. It is mainly found in the extract during the first hours of the experiment, but is almost totally recovered in the protein-bound fraction 48 hours after the injection. It is concluded that a part of the 35 S is absorbed directly from the rumen as unidentified sulfur-labelled compounds and is carried by the bloodstream, but a significant proportion of the 35 S introduced into the rumen as methionine is incorporated into microbial protein or enters the intestine directly [fr

Electron addition to alkyl cobalamins, coenzyme B12 and vitamin B12

International Nuclear Information System (INIS)

Rao, D.N.R.; Symons, M.C.R.

1983-01-01

Exposure of dilute solutions of methyl and ethyl cobalamins and coenzyme B 12 in dilute solutions (D 2 O+CD 3 OD) to 60 Co #betta#-rays at 77 K gave a single broad feature in the free-spin region assigned to electron-capture species with the excess electron largely confined to a π* corrin orbital. On warming above 77 K the methyl derivative gave a novel species with spectral features characteristic of an unpaired electron in the Co(dsub(x 2 -y 2 )) orbital. The other two substrates gave spectra due to Cosup(II)Bsub(12r) both on warming and after photolyses with visible light. The acetyl derivative gave an electron-capture species whose e.s.r. spectrum was characteristic of an electron in the Co(dsub(z 2 )) orbital, which on warming above 77 K changed to the normal Cosup(II)Bsub(12r) spectrum. The cyano derivative (vitamin B 12 ) gave electron addition into the Co(dsub(z 2 )) orbital, as evidenced by the large hyperfine coupling to 13 C from 13 CN ligands. On annealing, cyanide ions were lost irreversibly, Bsub(12r) being detected by e.s.r. spectroscopy. In contrast, the dicyano derivative on electron addition at 77 K gave a species containing only one 13 CN ligand. Hence in this case one CN - ligand was lost at 77 K, with no return of the dimethylbenzimidazole ligand. These results are discussed in terms of a new mechanism for electron-addition to alkyl cobalamins. (author)

QSAR study of benzimidazole derivatives inhibition on escherichia coli methionine Aminopeptidase

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Zahra Garkani-Nejad

2010-06-01

Full Text Available The paper describes a quantitative structure-activity relationship (QSAR study of IC50 values of benzimidazole derivatives on escherichia coli methionine aminopeptidase. The activity of the 32 inhibitors has been estimated by means of multiple linear regression (MLR and artificial neural network (ANN techniques. The results obtained using the MLR method indicate that the activity of derivatives of benzimidazoles on CoII-loaded escherichia coli methionine aminopeptidase depend on different parameters containing topological descriptors, Burden eigen values, 3D MoRSE descriptors and 2D autocorrelation descriptors. The best artificial neural network model is a fully-connected, feed forward back propagation network with a 5-4-1 architecture. Standard error for the training set using this network was 0.193 with correlation coefficient 0.996 and for the prediction set standard error was 1.41 with correlation coefficient 0.802. Comparison of the quality of the ANN with different MLR models showed that ANN has a better predictive power.

D-Methionine attenuated cisplatin-induced vestibulotoxicity through altering ATPase activities and oxidative stress in guinea pigs

International Nuclear Information System (INIS)

Cheng, P.-W.; Liu, S.-H.; Young, Y.-H.; Lin-Shiau, Shoei-Yn

2006-01-01

Cisplatin has been used as a chemotherapeutic agent to treat many kinds of malignancies. Its damage to the vestibulo-ocular reflex (VOR) system has been reported. However, the underlying biochemical change in the inner ear or central vestibular nervous system is not fully understood. In this study, we attempted to examine whether cisplatin-induced vestibulotoxicity and D-methionine protection were correlated with the changes of ATPase activities and oxidative stress of ampullary tissue of vestibules as well as cerebellar cortex (the inhibitory center of VOR system) of guinea pigs. By means of a caloric test coupled with electronystagmographic recordings, we found that cisplatin exposure caused a dose-dependent (1, 3, or 5 mg/kg) vestibular dysfunction as revealed by a decrease of slow phase velocity (SPV). In addition, cisplatin significantly inhibited the Na + , K + -ATPase and Ca 2+ -ATPase activities in the ampullary tissue with a good dose-response relationship but not those of cerebellar cortex. Regression analysis indicated that a decrease of SPV was well correlated with the reduction of Na + , K + -ATPase and Ca 2+ -ATPase activities of the ampullary tissue. D-Methionine (300 mg/kg) reduced both abnormalities of SPV and ATPase activities in a correlated manner. Moreover, cisplatin exposure led to a significant dose-dependent increase of lipid peroxidation and nitric oxide concentrations of the vestibules, which could be significantly suppressed by D-methionine. However, cisplatin did not alter the levels of lipid peroxidation and nitric oxide of the cerebellum. In conclusion, cisplatin inhibited ATPase activities and increased oxidative stress in guinea pig vestibular labyrinths. D-Methionine attenuated cisplatin-induced vestibulotoxicity associated with ionic disturbance through its antioxidative property

Increased amounts of D-enantiomer dependent on alkaline concentration in the synthesis of L-[methyl-11C]methionine

International Nuclear Information System (INIS)

Ishiwata, Kiichi; Ido, Tatsuo; Vaalburg, W.

1988-01-01

The presence of D-enantiomer in L-[methyl- 11 C]methionine prepared from [ 11 C]CH 3 I and L-homocysteine thiolactone, was measured by high performance liquid chromatography using a reverse-phase column with an eluent containing L-proline and cupric acetate. The amount of D-enantiomer increased with concentration of NaOH used. The reaction time, 2-10 min, and the reaction temperature, 40 0 -80 0 C, have only minor effect on the formation of D-enantiomer. No significant difference was found for three different lots of L-homocysteine thiolactone. At the highest concentration investigated, 1.0 M NaOH in 50% aqueous acetone, the percentage of D-enantiomer was found to be 7.7%. With 0.025 M NaOH used only 2.1% was measured. When L-[methyl- 11 C]methionine was incubated in 1.0 M NaOH, no conversion of L- into D-enantiomer was observed. (author)

Methionine metabolism and ethylene formation in etiolated pea stem sections

International Nuclear Information System (INIS)

Schilling, N.; Kende, H.

1979-01-01

Stem sections of etiolated pea seedlings (Pisum sativum L. cv. Alaska) were incubated overnight on tracer amounts of L-[U- 14 C]methionine and, on the following morning, on 0.1 millimolar indoleacetic acid to induce ethylene formation. Following the overnight incubation, over 70% of the radioactivity in the soluble fraction was shown to be associated with S-methylmethionine (SMM). The specific radioactivity of the ethylene evolved closely paralleled that of carbon atoms 3 and 4 of methionine extracted from the tissue and was always higher than that determined for carbon atoms 3 and 4 of extracted SMM. Overnight incubation of pea stem sections on 1 millimolar methionine enhanced indoleacetic acid-induced ethylene formation by 5 to 10%. Under the same conditions, 1 millimolar homocysteine thiolactone increased ethylene synthesis by 20 to 25%, while SMM within a concentration range of 0.1 to 10 millimolar did not influence ethylene production. When unlabeled methionine or homocysteine thiolactone was applied to stem sections which had been incubated overnight in L-[U- 14 C]methionine, the specific radioactivity of the ethylene evolved was considerably lowered. Application of unlabeled SMM reduced the specific radioactivity of ethylene only slightly

Robotic synthesis of [carbon-11]methionine

International Nuclear Information System (INIS)

Korsakov, M.V.; Kisselev, M.Y.; Solovyov, D.; Horti, A.G.; Vasilev, A.; Nilsson, L.E.; Ulin, J.

1992-01-01

[ 11 C]Methionine was prepared in a fully automated robotic synthesis, using the SCANDITRONIX robotic system starting from [ 11 C]I and homocysteine thiolactone. The product was purified using solid phase extraction on anionic exchange cartridges. The decay corrected yield was 60% based on CH 3 I and 16 min synthesis time. The radiochemical purity was 98-99% and the chemical impurities were: homocysteine 0.05-0.07 mg/ml, homocystine 0.005 mg/ml, 'cold' methionine 0.03-0.05 mg/ml, and homocysteine thiolactone 0.0008-0.002 mg/ml. The total procedure takes 30 min from EOB. (author) 6 figs., 3 tabs

Gender differences in methionine accumulation and metabolism in freshly isolated mouse hepatocytes: Potential roles in toxicity

International Nuclear Information System (INIS)

Dever, Joseph T.; Elfarra, Adnan A.

2009-01-01

L-Methionine (Met) is hepatotoxic at high concentrations. Because Met toxicity in freshly isolated mouse hepatocytes is gender-dependent, the goal of this study was to assess the roles of Met accumulation and metabolism in the increased sensitivity of male hepatocytes to Met toxicity compared with female hepatocytes. Male hepatocytes incubated with Met (30 mM) at 37 o C exhibited higher levels of intracellular Met at 0.5, 1.0, and 1.5 h, respectively, compared to female hepatocytes. Conversely, female hepatocytes had higher levels of S-adenosyl-L-methionine compared to male hepatocytes. Female hepatocytes also exhibited higher L-methionine-L-sulfoxide levels relative to control hepatocytes, whereas the increases in L-methionine-D-sulfoxide (Met-D-O) levels were similar in hepatocytes of both genders. Addition of aminooxyacetic acid (AOAA), an inhibitor of Met transamination, significantly increased Met levels at 1.5 h and increased Met-D-O levels at 1.0 and 1.5 h only in Met-exposed male hepatocytes. No gender differences in cytosolic Met transamination activity by glutamine transaminase K were detected. However, female mouse liver cytosol exhibited higher methionine-DL-sulfoxide (MetO) reductase activity than male mouse liver cytosol at low (0.25 and 0.5 mM) MetO concentrations. Collectively, these results suggest that increased cellular Met accumulation, decreased Met transmethylation, and increased Met and MetO transamination in male mouse hepatocytes may be contributing to the higher sensitivity of the male mouse hepatocytes to Met toxicity in comparison with female mouse hepatocytes.

Methionine kinetics and balance at the 1985 FAO/WHO/UNU intake requirement in adult men studied with L-[2H3-methyl-1-13C]methionine as a tracer

International Nuclear Information System (INIS)

Young, V.R.; Wagner, D.A.; Burini, R.; Storch, K.J.

1991-01-01

The upper range of the requirement for methionine plus cystine in healthy adults was proposed in 1985 by FAO/WHO/UNU to be 13 mg.kg body wt-1.d-1. To explore the validity of this estimate, five healthy, young adult men were given for 7 d a diet based on an L-amino acid mixture supplying 13 mg methionine.kg-1.d-1 (87 mumol.kg-1.d-1) without cystine. Constant intravenous infusions of L-[2H3-methyl-1-13C]methionine were given on days 5 and 7 while subjects were in the fed and postabsorptive states, respectively. Estimates were made of methionine oxidation, and daily methionine balance was derived from the intake-oxidation data. For the five subjects, methionine balances were -0.9, +0.7, +3.5, -3.1, and -3.8 mg kg-1.d-1, or -6, +5, +23, -21, and -26 mumol.kg-1.d-1. These findings lead to the conclusion that the upper range of the requirement for methionine plus cystine probably exceeds 13 mg.kg-1.d-1 in healthy young adults. The implications of this conclusion for establishing an appropriate amount of sulfur amino acids in an amino acid requirement pattern for adults is discussed

Targeting methionine cycle as a potential therapeutic strategy for immune disorders.

Science.gov (United States)

Li, Heng; Lu, Huimin; Tang, Wei; Zuo, Jianping

2017-08-23

Methionine cycle plays an essential role in regulating many cellular events, especially transmethylation reactions, incorporating the methyl donor S-adenosylmethionine (SAM). The transmethylations and substances involved in the cycle have shown complicated effects and mechanisms on immunocytes developments and activations, and exert crucial impacts on the pathological processes in immune disorders. Areas covered: Methionine cycle has been considered as an effective means of drug developments. This review discussed the role of methionine cycle in immune responses and summarized the potential therapeutic strategies based on the cycle, including SAM analogs, methyltransferase inhibitors, S-adenosylhomocysteine hydrolase (SAHH) inhibitors, adenosine receptors specific agonists or antagonists and homocysteine (Hcy)-lowering reagents, in treating human immunodeficiency virus (HIV) infections, systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), multiple sclerosis (MS), systemic sclerosis (SSc) and other immune disorders. Expert opinion: New targets and biomarkers grown out of methionine cycle have developed rapidly in the past decades. However, impacts of epigenetic regulations on immune disorders are unclear and whether the substances in methionine cycle can be clarified as biomarkers remains controversial. Therefore, further elucidation on the role of epigenetic regulations and substances in methionine cycle may contribute to exploring the cycle-derived biomarkers and drugs in immune disorders.

Dry-extrusion of Asian Carp to supplement natural methionine for organic poultry production

Science.gov (United States)

Methionine, a sulfur containing amino acid, is essential for healthy poultry production. Synthetic methionine is commonly used as a supplement in conventional poultry. However, for organic poultry in the United States, a natural, cost effective source of methionine that can replace synthetic methion...

A Frameshift Mutation in the Cubilin Gene (CUBN) in Border Collies with Imerslund-Gräsbeck Syndrome (Selective Cobalamin Malabsorption)

Science.gov (United States)

Owczarek-Lipska, Marta; Jagannathan, Vidhya; Drögemüller, Cord; Lutz, Sabina; Glanemann, Barbara

2013-01-01

Imerslund-Gräsbeck syndrome (IGS) or selective cobalamin malabsorption has been described in humans and dogs. IGS occurs in Border Collies and is inherited as a monogenic autosomal recessive trait in this breed. Using 7 IGS cases and 7 non-affected controls we mapped the causative mutation by genome-wide association and homozygosity mapping to a 3.53 Mb interval on chromosome 2. We re-sequenced the genome of one affected dog at ∼10× coverage and detected 17 non-synonymous variants in the critical interval. Two of these non-synonymous variants were in the cubilin gene (CUBN), which is known to play an essential role in cobalamin uptake from the ileum. We tested these two CUBN variants for association with IGS in larger cohorts of dogs and found that only one of them was perfectly associated with the phenotype. This variant, a single base pair deletion (c.8392delC), is predicted to cause a frameshift and premature stop codon in the CUBN gene. The resulting mutant open reading frame is 821 codons shorter than the wildtype open reading frame (p.Q2798Rfs*3). Interestingly, we observed an additional nonsense mutation in the MRC1 gene encoding the mannose receptor, C type 1, which was in perfect linkage disequilibrium with the CUBN frameshift mutation. Based on our genetic data and the known role of CUBN for cobalamin uptake we conclude that the identified CUBN frameshift mutation is most likely causative for IGS in Border Collies. PMID:23613799

Prostaglandin H synthase immunoreactivity in human gut. An immunohistochemical study

DEFF Research Database (Denmark)

Mikkelsen, H B; Rumessen, J J; Qvortrup, Klaus

1991-01-01

Prostaglandins exhibit a variety of actions on intestinal smooth muscle depending upon the type, dose and muscle layer studied. As the cellular origin of prostaglandin H (PGH) synthase has not been established with certainty in the human gut wall, we studied the localization of PGH synthase...

A Comparison of the Effects of Neuronal Nitric Oxide Synthase and Inducible Nitric Oxide Synthase Inhibition on Cartilage Damage

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Nevzat Selim Gokay

2016-01-01

Full Text Available The objective of this study was to investigate the effects of selective inducible nitric oxide synthase and neuronal nitric oxide synthase inhibitors on cartilage regeneration. The study involved 27 Wistar rats that were divided into five groups. On Day 1, both knees of 3 rats were resected and placed in a formalin solution as a control group. The remaining 24 rats were separated into 4 groups, and their right knees were surgically damaged. Depending on the groups, the rats were injected with intra-articular normal saline solution, neuronal nitric oxide synthase inhibitor 7-nitroindazole (50 mg/kg, inducible nitric oxide synthase inhibitor amino-guanidine (30 mg/kg, or nitric oxide precursor L-arginine (200 mg/kg. After 21 days, the right and left knees of the rats were resected and placed in formalin solution. The samples were histopathologically examined by a blinded evaluator and scored on 8 parameters. Although selective neuronal nitric oxide synthase inhibition exhibited significant (P=0.044 positive effects on cartilage regeneration following cartilage damage, it was determined that inducible nitric oxide synthase inhibition had no statistically significant effect on cartilage regeneration. It was observed that the nitric oxide synthase activation triggered advanced arthrosis symptoms, such as osteophyte formation. The fact that selective neuronal nitric oxide synthase inhibitors were observed to have mitigating effects on the severity of the damage may, in the future, influence the development of new agents to be used in the treatment of cartilage disorders.

Utility of “1”1C -methionine PET/CT in neuro-oncology

International Nuclear Information System (INIS)

Casas Parera, I.; Igirio Gamero, J.L.; Báez, A.; Tafur Canabal, J.G.; Báez, M.; Kuchkaryan, V.; B lumenkrantz, Y.; Bruno, G.

2013-01-01

Positron emission tomography (PET) with “1”1C-methionine (“1”1C-methionine PET/CT) is a new technique used to evaluate primary central nervous system (CNS) tumors. We describe our experience regarding the first 4 patients with glial tumors and “1”1C-methionine PET/CT. This is a descriptive, observational and prospective study of 4 patients between 38-50 years of age, with different gliomas (WHO classification). MRI and “1”1C-methionine PET/CT were performed in all cases. Case 1, gliomatosis cerebri grade II post-radiotherapy. Case 2, oligodendroglioma grade II diagnosed and treated with radiotherapy in 1993. Case 3, glioblastoma grade IV post-radiotherapy + temozolomide. Case 4, anaplastic oligoastrocytoma grade III post-radiotherapy + temozolomide. The pattern of “1”1C-methionine uptake compared with MRI showed tumor progression in cases 1, 3 and 4, and in case 2 showed uptake although the final diagnosis was pseudoprogression. Unlike “1”8fluordeoxiglucose PET/TC, “1”1C-methionine uptake in normal brain tissue and pseudoprogression is low, and gliomas are displayed as metabolically active areas. The “1”1C-methionine PET/CT provided valuable information on the tumoral behavior and extension, although in one case presented did not differentiate tumor progression from pseudoprogression. “1”1C-methionine PET/CT could be a useful tool in the study and follow-up to patients with gliomas. (authors) [es

Cobalamin Deficiency: Clinical Picture and Radiological Findings

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Chiara Briani

2013-11-01

Full Text Available Vitamin B12 deficiency causes a wide range of hematological, gastrointestinal, psychiatric and neurological disorders. Hematological presentation of cobalamin deficiency ranges from the incidental increase of mean corpuscular volume and neutrophil hypersegmentation to symptoms due to severe anemia, such as angor, dyspnea on exertion, fatigue or symptoms related to congestive heart failure, such as ankle edema, orthopnea and nocturia. Neuropsychiatric symptoms may precede hematologic signs and are represented by myelopathy, neuropathy, dementia and, less often, optic nerve atrophy. The spinal cord manifestation, subacute combined degeneration (SCD, is characterized by symmetric dysesthesia, disturbance of position sense and spastic paraparesis or tetraparesis. The most consistent MRI finding is a symmetrical abnormally increased T2 signal intensity confined to posterior or posterior and lateral columns in the cervical and thoracic spinal cord. Isolated peripheral neuropathy is less frequent, but likely overlooked. Vitamin B12 deficiency has been correlated negatively with cognitive functioning in healthy elderly subjects. Symptoms include slow mentation, memory impairment, attention deficits and dementia. Optic neuropathy occurs occasionally in adult patient. It is characterized by symmetric, painless and progressive visual loss. Parenteral replacement therapy should be started soon after the vitamin deficiency has been established.

Digestible methionine + cystine requirement for Nile tilapia from 550 to 700 g

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Mariana Michelato

2013-01-01

Full Text Available This trial was conducted to determine the dietary digestible methionine + cystine requirement of Nile tilapia (550 to 700 g based on the ideal protein concept. Six hundred fish were distributed in a completely randomized design with five treatments and four replicates, with 30 fish per experimental unit. The fish were fed diets containing approximately 262 g of digestible protein/kg, 3,040 kcal of digestible energy/kg and 7.90, 9.40, 10.90, 12.40 or 13.90 g of methionine + cystine/kg. The fish were hand-fed three times a day until apparent satiation for 30 days. No effects of dietary methionine + cystine on feed conversion ratio, daily protein deposition, whole body moisture, fillet moisture, crude protein, ether extract and ash, plasmatic HDL and LDL cholesterol were observed. Dietary methionine resulted in a linear increase in whole body protein and linear reduction in lipid deposition rate, hepatosomatic index, whole body ether extract and ash, plasmatic total cholesterol, plasmatic total lipids and plasmatic triglycerides. According to the Linear Response Plateau, the daily weight gain and fillet yield increased up to a level of 9.00 and 9.90 g methionine + cystine/kg of diet, respectively. The digestible methionine + cystine requirement of Nile tilapia is 9.00 g/kg for weight gain and 9.90 g/kg for fillet yield, corresponding to methionine + cystine:lysine ratios of 0.60 and 0.66, respectively.

Oxidation of protein tyrosine or methionine residues: From the amino acid to the peptide

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Berges, J [Universite Pierre et Marie Curie, UMR 7616, Laboratoire de Chimie Theorique, 75005 Paris (France); Trouillas, P [EA 4021 Faculte de Pharmacie, 2 Rue du Dr. Marcland, 87025 Limoges Cedex (France); Houee-Levin, C, E-mail: jb@lct.jussieu.fr, E-mail: patrick.trouillas@unilim.fr, E-mail: chantal.houee@u-psud.fr [Universite Paris Sud, UMR 8000, Laboratoire de Chimie Physique, 91405 Orsay (France) (France)

2011-01-01

Methionine and tyrosine are competing targets of oxidizing free radicals in peptides or proteins. The first step is the addition of OH radicals either on the sulphur atom of methionine, followed by OH{sup -} elimination, or on the aromatic cycle of tyrosine. The next step can be stabilization of methionine radical cation by a two centre-three electron bond, or intramolecular electron transfer from tyrosine to the methionine radical cation. In this latter case a tyrosine radical is formed, which appears deprotonated. In a first step we have compared the stability of the OH radical adducts on Methionine or on Tyrosine. In agreement with experimental results, the thermodynamical data indicate that the OH adduct on Tyrosine and the radical cation are more stable than those on methionine. In a second step we have investigated the stabilization of the radical cations of Methionine by formation of intramolecular S:X two-center three-electron bond (X=S, N, O). Finally we have compared the spin densities on separated amino acids to that in a radical pentapeptide, methionine enkephalin. One observes a delocalisation of the orbital of the odd electron on the sulfur atom of Met and on the cycle of Tyr. The peptidic chain is also concerned.

Oxidation of protein tyrosine or methionine residues: From the amino acid to the peptide

International Nuclear Information System (INIS)

Berges, J; Trouillas, P; Houee-Levin, C

2011-01-01

Methionine and tyrosine are competing targets of oxidizing free radicals in peptides or proteins. The first step is the addition of OH radicals either on the sulphur atom of methionine, followed by OH - elimination, or on the aromatic cycle of tyrosine. The next step can be stabilization of methionine radical cation by a two centre-three electron bond, or intramolecular electron transfer from tyrosine to the methionine radical cation. In this latter case a tyrosine radical is formed, which appears deprotonated. In a first step we have compared the stability of the OH radical adducts on Methionine or on Tyrosine. In agreement with experimental results, the thermodynamical data indicate that the OH adduct on Tyrosine and the radical cation are more stable than those on methionine. In a second step we have investigated the stabilization of the radical cations of Methionine by formation of intramolecular S:X two-center three-electron bond (X=S, N, O). Finally we have compared the spin densities on separated amino acids to that in a radical pentapeptide, methionine enkephalin. One observes a delocalisation of the orbital of the odd electron on the sulfur atom of Met and on the cycle of Tyr. The peptidic chain is also concerned.

Effects of Glycine, Water, Ammonia, and Ammonium Bicarbonate on the Oligomerization of Methionine

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Huang, Rui; Furukawa, Yoshihiro; Otake, Tsubasa; Kakegawa, Takeshi

2017-06-01

The abiotic oligomerization of amino acids may have created primordial, protein-like biological catalysts on the early Earth. Previous studies have proposed and evaluated the potential of diagenesis for the amino acid oligomerization, simulating the formation of peptides that include glycine, alanine, and valine, separately. However, whether such conditions can promote the formation of peptides composed of multiple amino acids remains unclear. Furthermore, the chemistry of pore water in sediments should affect the oligomerization and degradation of amino acids and oligomers, but these effects have not been studied extensively. In this study, we investigated the effects of water, ammonia, ammonium bicarbonate, pH, and glycine on the oligomerization and degradation of methionine under high pressure (150 MPa) and high temperature conditions (175 °C) for 96 h. Methionine is more difficult to oligomerize than glycine and methionine dimer was formed in the incubation of dry powder of methionine. Methionine oligomers as long as trimers, as well as methionylglycine and glycylmethionine, were formed under every condition with these additional compounds. Among the compounds tested, the oligomerization reaction rate was accelerated by the presence of water and by an increase in pH. Ammonia also increased the oligomerization rate but consumed methionine by side reactions and resulted in the rapid degradation of methionine and its peptides. Similarly, glycine accelerated the oligomerization rate of methionine and the degradation of methionine, producing water, ammonia, and bicarbonate through its decomposition. With Gly, heterogeneous dimers (methionylglycine and glycylmethionine) were formed in greater amounts than with other additional compounds although smaller amount of these heterogeneous dimers were formed with other additional compounds. These results suggest that accelerated reaction rates induced by water and co-existing reactive compounds promote the oligomerization

Egg quality of quails fed low methionine diet supplemented with betaine

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Ratriyanto, A.; Indreswari, R.; Dewanti, R.; Wahyuningsih, S.

2018-03-01

This experiment investigated the effect of betaine supplementation to low methionine diet on egg quality of quails. A total of 340 laying quails (Coturnix coturnix japonica) was divided into 4 dietary treatments with 5 replicates of 17 quails each. The experiment was assigned in a completely randomized design. The four dietary treatments were the low methionine diet (0.3% methionine) without betaine supplementation and the low methionine diet supplemented with 0.07, 0.14, and 0.21% betaine. The experimental diets were applied for 8 weeks and the egg quality traits were measured at the age of 16 and 20 weeks. The data were subjected to analysis of variance, and when the treatment indicated significant effect, it was continued to orthogonal polynomial test to determine the optimum level of betaine. Increasing dietary levels of betaine increased the fat content of the egg with the linear regression of y = 11.0949 + 4.1914x (R2 = 0.18). However, supplementation of betaine did not affect protein content, yolk, albumen, and eggshell percentage. It can be concluded that betaine supplementation up to 0.21% to low methionine diet only had little effect in improving the quality traits of quail eggs.

Increasing levels of dietary crystalline methionine affect plasma methionine profiles, ammonia excretion, and the expression of genes related to the hepatic intermediary metabolism in rainbow trout (Oncorhynchus mykiss)

DEFF Research Database (Denmark)

Rolland, Marine; Skov, Peter Vilhelm; Larsen, Bodil Katrine

2016-01-01

Strictly carnivorous fish with high requirements for dietary protein, such as rainbow trout (Oncorhynchus mykiss) are interesting models for studying the role of amino acids as key regulators of intermediary metabolism. Methionine is an essential amino acid for rainbow trout, and works as a signa......Strictly carnivorous fish with high requirements for dietary protein, such as rainbow trout (Oncorhynchus mykiss) are interesting models for studying the role of amino acids as key regulators of intermediary metabolism. Methionine is an essential amino acid for rainbow trout, and works...... as a signalling factor in different metabolic pathways. The study investigated the effect of increasing dietary methionine intake on the intermediary metabolism in the liver of juvenile rainbow trout. For this purpose, five diets were formulated with increasing methionine levels from 0.60 to 1.29% dry matter....... The diets were fed in excess for six weeks before three sampling campaigns carried out successively to elucidate (i) the hepatic expression of selected genes involved in lipid, glucose and amino acid metabolism; (ii) the postprandial ammonia excretion; and (iii) the postprandial plasma methionine...

Endothelium derived nitric oxide synthase negatively regulates the PDGF-survivin pathway during flow-dependent vascular remodeling.

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Jun Yu

Full Text Available Chronic alterations in blood flow initiate structural changes in vessel lumen caliber to normalize shear stress. The loss of endothelial derived nitric oxide synthase (eNOS in mice promotes abnormal flow dependent vascular remodeling, thus uncoupling mechanotransduction from adaptive vascular remodeling. However, the mechanisms of how the loss of eNOS promotes abnormal remodeling are not known. Here we show that abnormal flow-dependent remodeling in eNOS knockout mice (eNOS (-/- is associated with activation of the platelet derived growth factor (PDGF signaling pathway leading to the induction of the inhibitor of apoptosis, survivin. Interfering with PDGF signaling or survivin function corrects the abnormal remodeling seen in eNOS (-/- mice. Moreover, nitric oxide (NO negatively regulates PDGF driven survivin expression and cellular proliferation in cultured vascular smooth muscle cells. Collectively, our data suggests that eNOS negatively regulates the PDGF-survivin axis to maintain proportional flow-dependent luminal remodeling and vascular quiescence.

Synthesis and characterization of nido-carborane-cobalamin conjugates

International Nuclear Information System (INIS)

Hogenkamp, Harry P.C.; Collins, Douglas A.; Live, David; Benson, Linda M.; Naylor, Stephen

2000-01-01

Three vitamin B 12 (cyanocobalamin) conjugates bearing one nido-carborane molecule or two nido-carborane molecules linked to the propionamide side chains via a four carbon linker have been synthesized. Reaction of o-carboranoylchloride with 1,4-diaminobutane in pyridine produced nido-carboranoyl(4-amidobutyl)amine, which was linked to the b- and d-monocarboxylic acids and the b,d-dicarboxylic acid of cyanocobalamin. Mass spectrometry analysis as well as 11 B nuclear magnetic resonance demonstrated that during the reaction of o-carboranonylchloride with diaminobutane one of the boron atoms was eliminated. In vitro biological activity of the cyanocobalamin-nido-carborane conjugates was assessed by the unsaturated vitamin B 12 binding capacity assay. When compared with 57 Co cyanocobalamin, the biological activity of cyanocobalamin-b-nido-carborane, cyanocobalamin-d-nido-carborane, and cyanocobalamin-b-d-bis-nido-carborane conjugates were 92.93%, 35.75%, and 37.02%, respectively. These findings suggest that the 10 B cobalamin conjugates might be useful agents in treating malignant tumors via neutron capture therapy

Relationship Between the Plasma Methionine {sup 14}C Activity and the Level of Some Other Essential Amino Acids

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Boldizsar, H.; Pethes, G.; Kemeny, A. [Radioisotope Laboratory, Department of Physiology, University of Veterinary Science, Budapest (Hungary)

1968-07-01

At present there exists no sufficiently accurate and rapid method of determining the limiting order of amino acids. Labelled amino acid was used as an index to measure the rate of protein synthesis. Twenty-six leghorn cocks were used: 50 {mu}Ci {sup 14}C-methionine was injected, and 30 min later 200 mg of lysine, glycine, valine, alpha-amino-butyric-acid, and a mixture of lysine, tryptophane, methionine and phenylalanine, were added by injection. The total activity of plasma, the activity of the protein fraction, the fat- and water-soluble fractions, and that of urine, were determined. Between the 60th and 120th minutes, after the labelled methionine was injected, the total plasma- and protein-bound activity increased as follows: glycine (38%), the mixture (34%), lysine (31%), alpha-amino- butyric-acid (28%), but decreased in the case of valine (11%). In accordance with these, the free methionine activity in the plasma decreased proportionally. The extent of the changes depended on the place of the respective amino acids in the limiting order. On the basis of results the authors discuss a method that would be suitable for quantitative and rapid measurements of the insufficiency of essential amino acids in foodstuffs. (author)

Ontogeny of methionine utilization and splanchnic uptake in critically ill children

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To determine the rates of methionine splanchnic uptake and utilization in critically ill pediatric patients, we used two kinetic models: the plasma methionine enrichment,and the "intracellular" homocysteine enrichment. Twenty-four patients, eight infants, eight children, and eight adolescents, were ...

Interleukin-2-induced survival of natural killer (NK) cells involving phosphatidylinositol-3 kinase-dependent reduction of ceramide through acid sphingomyelinase, sphingomyelin synthase, and glucosylceramide synthase.

Science.gov (United States)

Taguchi, Yoshimitsu; Kondo, Tadakazu; Watanabe, Mitsumasa; Miyaji, Michihiko; Umehara, Hisanori; Kozutsumi, Yasunori; Okazaki, Toshiro

2004-11-15

Interleukin 2 (IL-2) rescued human natural killer (NK) KHYG-1 cells from apoptosis along with a reduction of ceramide. Conversely, an increase of ceramide inhibited IL-2-rescued survival. IL-2 deprivation-induced activation of acid sphingomyelinase (SMase) and inhibition of glucosylceramide synthase (GCS) and sphingomyelin synthase (SMS) were normalized by IL-2 supplementation. A phosphatidyl inositol-3 (PI-3) kinase inhibitor, LY294002, inhibited IL-2-rescued survival, but a mitogen-activated protein kinase inhibitor, PD98059, and an inhibitor of Janus tyrosine kinase/signal transducer and activator of transcription pathway, AG490, did not. LY294002 inhibited IL-2-induced reduction of ceramide through activation of acid SMase and inhibition of GCS and SMS, suggesting the positive involvement of PI-3 kinase in ceramide reduction through enzymatic regulation. Indeed, a constitutively active PI-3 kinase enhanced growth rate and ceramide reduction through inhibition of acid SMase and activation of GCS and SMS. Further, LY294002 inhibited IL-2-induced changes of transcriptional level as well as mRNA and protein levels in acid SMase and GCS but did not affect the stability of the mRNAs. These results suggest that PI-3 kinase-dependent reduction of ceramide through regulation of acid SMase, GCS, and SMS plays a role in IL-2-rescued survival of NK cells.

Three family members with elevated plasma cobalamin, transcobalamin and soluble transcobalamin receptor (sCD320)

DEFF Research Database (Denmark)

Hoffmann-Lücke, Elke; Arendt, Johan F B; Nissen, Peter H

2013-01-01

deficiency were found. DNA sequencing of the TCN2 gene revealed several known polymorphisms not associated with highly elevated transcobalamin levels. Upon gel filtration, sCD320 eluted as a larger molecule than previously reported. By incubation with anti-transcobalamin antibodies, we precipitated both...... transcobalamin and part of sCD320. CONCLUSIONS: The high cobalamin levels were mainly explained by high levels of holoTC, possibly caused by complex formation with its soluble receptor, sCD320. The family occurrence points to a genetic explanation....

Clinical characteristics of hemolytic uremic syndrome secondary to cobalamin C disorder in Chinese children.

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Li, Qi-Liang; Song, Wen-Qi; Peng, Xiao-Xia; Liu, Xiao-Rong; He, Le-Jian; Fu, Li-Bing

2015-08-01

The present study was undertaken to investigate the clinical characteristics of hemolytic uremic syndrome (HUS) secondary to cobalamin C disorder (cbl-C disorder). We reviewed retrospectively the medical records of 3 children with HUS secondary to cbl-C disorder who had been treated between April 1, 2009 and October 31, 2013. The 3 patients with HUS secondary to cbl-C disorder presented with progressive hemolytic anemia, acute renal failure, thrombocytopenia, poor feeding, and failure to thrive. Two of the 3 patients once had high blood pressure. The mutations of c.609G>A (p.W203X), c.217C>T (p.R73X) and c.365A>T (p.H122L) in the methylmalonic aciduria (cobalamin deficiency) cbl-C type, with homocystinuria gene were detected in the 3 patients. In these patients the levels of lactate dehydrogenase and homocysteine in serum were elevated and the level of methylmalonic acid (MMA) in urine was also elevated. After treatment with hydroxocobalamin, 2 patients were discharged with no obvious abnormal growth and neurological development and 1 patient died of multiple organ failure. The results of this study demonstrated that cbl-C disorder should be investigated in any child presenting with HUS. The high concentrations of homocysteine and MMA could be used for timely recognization of the disease. Once the high levels of plasma homocystein and/or plasma or urine MMA are detected, the treatment with parenteral hydroxocobalamin should be prescribed immediately. The early diagnosis and treatment would contribute to the good prognosis of the disease.

A Prospective, Placebo-Controlled Pilot Evaluation of the Effect of Omeprazole on Serum Calcium, Magnesium, Cobalamin, Gastrin Concentrations, and Bone in Cats.

Science.gov (United States)

Gould, E; Clements, C; Reed, A; Giori, L; Steiner, J M; Lidbury, J A; Suchodolski, J S; Brand, M; Moyers, T; Emery, L; Tolbert, M K

2016-05-01

Chronic proton pump inhibitor administration has been associated with electrolyte and cobalamin deficiency, disrupted bone homeostasis, hypergastrinemia, and rebound acid hypersecretion in humans. It is unknown if this occurs in cats. Prolonged oral omeprazole results in altered bone mineral density or content, serum calcium, magnesium, cobalamin, and gastrin concentrations in healthy cats. Six healthy adult DSH cats. In a within subjects, before and after design, cats received placebo followed by omeprazole (0.83-1.6 mg/kg PO q12h) for 60 days each. Analysis of serum calcium, magnesium, cobalamin, and gastrin concentrations was performed on days 0, 30, and 60. Bone density and content were evaluated on days 0 and 60 of each intervention. Continuous data were analyzed using a two-way ANOVA (α = 0.006). On day 60 of omeprazole administration, continuous intragastric pH monitoring was performed in 2 cats to evaluate the effects of abrupt withdrawal of omeprazole. No significant changes were detected between treatments for any variables, except serum gastrin, which was significantly higher during omeprazole treatment in comparison to placebo (P = 0.002). Evidence of gastric hyperacidity was seen in both cats in which intragastric pH monitoring was performed following cessation of omeprazole. Although further studies with larger populations of cats will be needed to draw any definitive conclusions, these preliminary results suggest that prolonged PPI treatment results in hypergastrinemia and abrupt PPI withdrawal might result in RAH in cats. Copyright © 2016 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Hemolytic uremic syndrome (HUS) secondary to cobalamin C (cblC) disorder.

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Sharma, Ajay P; Greenberg, Cheryl R; Prasad, Asuri N; Prasad, Chitra

2007-12-01

Diarrhea-positive hemolytic uremic syndrome (HUS) is a common cause of acute renal failure in children. Diarrhea-negative (D-), or atypical HUS, is etiologically distinct. A Medline search identified seven previously reported D- cases of HUS secondary to cobalamin C (cblC) disease presenting in infancy. An infantile presentation is reported to be associated with a high mortality rate (6/7 cases). We describe the results of a 5-year longitudinal follow-up in a child diagnosed with D- HUS secondary to cblC disease in infancy. Mutation analysis in this patient identified homozygosity for the 271 dupA mutation (c.271 dupA) in the cblC MMACHC gene. We briefly review the published experience in cblC-associated HUS to highlight the clinical characteristics of this uncommon, but potentially treatable, condition.

Identification of ABC transporters acting in vitamin B12 metabolism in Caenorhabditis elegans.

Science.gov (United States)

McDonald, Megan K; Fritz, Julie-Anne; Jia, Dongxin; Scheuchner, Deborah; Snyder, Floyd F; Stanislaus, Avalyn; Curle, Jared; Li, Liang; Stabler, Sally P; Allen, Robert H; Mains, Paul E; Gravel, Roy A

2017-12-01

Vitamin B 12 (cobalamin, Cbl) is a micronutrient essential to human health. Cbl is not utilized as is but must go through complex subcellular and metabolic processing to generate two cofactor forms: methyl-Cbl for methionine synthase, a cytosolic enzyme; and adenosyl-Cbl for methylmalonyl-CoA mutase, a mitochondrial enzyme. Some 10-12 human genes have been identified responsible for the intracellular conversion of Cbl to cofactor forms, including genes that code for ATP-binding cassette (ABC) transporters acting at the lysosomal and plasma membranes. However, the gene for mitochondrial uptake is not known. We hypothesized that ABC transporters should be candidates for other uptake and efflux functions, including mitochondrial transport, and set out to screen ABC transporter mutants for blocks in Cbl utilization using the nematode roundworm Caenorhabditis elegans. Thirty-seven mutant ABC transporters were screened for the excretion of methylmalonic acid (MMA), which should result from loss of Cbl transport into the mitochondria. One mutant, wht-6, showed elevated MMA excretion and reduced [ 14 C]-propionate incorporation, pointing to a functional block in methylmalonyl-CoA mutase. In contrast, the wht-6 mutant appeared to have a normal cytosolic pathway based on analysis of cystathionine excretion, suggesting that cytosolic methionine synthase was functioning properly. Further, the MMA excretion in wht-6 could be partially reversed by including vitamin B 12 in the assay medium. The human ortholog of wht-6 is a member of the G family of ABC transporters. We propose wht-6 as a candidate for the transport of Cbl into mitochondria and suggest that a member of the corresponding ABCG family of ABC transporters has this role in humans. Our ABC transporter screen also revealed that mrp-1 and mrp-2 mutants excreted lower MMA than wild type, suggesting they were concentrating intracellular Cbl, consistent with the cellular efflux defect proposed for the mammalian MRP1 ABC

The First International Mini-Symposium on Methionine Restriction and Lifespan

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Gene eAbles

2014-05-01

Full Text Available It has been 20 years since the Orentreich Foundation for the Advancement of Science, under the leadership Dr. Norman Orentreich, first reported that low methionine (Met ingestion by rats extends lifespan [1]. Since then, several studies have replicated the effects of dietary methionine restriction (MR in delaying age-related diseases [2–5]. We report the abstracts from the First International Mini-Symposium on Methionine Restriction and Lifespan held in Tarrytown, NY last September 2013. The goals were 1 to gather researchers with an interest in methionine restriction and lifespan, 2 to exchange knowledge, 3 to generate ideas for future investigations, and 4 to strengthen relationships within this community. The presentations highlighted the importance of research on cysteine, growth hormone (GH, and ATF4 in the paradigm of aging. In addition, the effects of dietary restriction or MR in the kidneys, liver, bones and the adipose tissue were discussed. The symposium also emphasized the value of other species, e.g. the naked mole rat, Brandt’s bat and drosophila in aging research. Overall, the symposium consolidated scientists with similar research interests and provided opportunities to conduct future collaborative studies.

Functional loss of two ceramide synthases elicits autophagy-dependent lifespan extension in C. elegans.

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Mai-Britt Mosbech

Full Text Available Ceramide and its metabolites constitute a diverse group of lipids, which play important roles as structural entities of biological membranes as well as regulators of cellular growth, differentiation, and development. The C. elegans genome comprises three ceramide synthase genes; hyl-1, hyl-2, and lagr-1. HYL-1 function is required for synthesis of ceramides and sphingolipids containing very long acyl-chains (≥C24, while HYL-2 is required for synthesis of ceramides and sphingolipids containing shorter acyl-chains (≤C22. Here we show that functional loss of HYL-2 decreases lifespan, while loss of HYL-1 or LAGR-1 does not affect lifespan. We show that loss of HYL-1 and LAGR-1 functions extend lifespan in an autophagy-dependent manner, as knock down of the autophagy-associated gene ATG-12 abolishes hyl-1;lagr-1 longevity. The transcription factors PHA-4/FOXA, DAF-16/FOXO, and SKN-1 are also required for the observed lifespan extension, as well as the increased number of autophagosomes in hyl-1;lagr-1 animals. Both autophagic events and the transcription factors PHA-4/FOXA, DAF-16, and SKN-1 have previously been associated with dietary restriction-induced longevity. Accordingly, we find that hyl-1;lagr-1 animals display reduced feeding, increased resistance to heat, and reduced reproduction. Collectively, our data suggest that specific sphingolipids produced by different ceramide synthases have opposing roles in determination of C. elegans lifespan. We propose that loss of HYL-1 and LAGR-1 result in dietary restriction-induced autophagy and consequently prolonged longevity.

Structural Basis of Catalysis in the Bacterial Monoterpene Synthases Linalool Synthase and 1,8-Cineole Synthase

OpenAIRE

Karuppiah, Vijaykumar; Ranaghan, Kara E.; Leferink, Nicole G. H.; Johannissen, Linus O.; Shanmugam, Muralidharan; Ní Cheallaigh, Aisling; Bennett, Nathan J.; Kearsey, Lewis J.; Takano, Eriko; Gardiner, John M.; van der Kamp, Marc W.; Hay, Sam; Mulholland, Adrian J.; Leys, David; Scrutton, Nigel S.

2017-01-01

Terpenoids form the largest and stereochemically most diverse class of natural products, and there is considerable interest in producing these by biocatalysis with whole cells or purified enzymes, and by metabolic engineering. The monoterpenes are an important class of terpenes and are industrially important as flavors and fragrances. We report here structures for the recently discovered Streptomyces clavuligerus monoterpene synthases linalool synthase (bLinS) and 1,8-cineole synthase (bCinS)...

Degradation of platinum based anticancer drugs by methionine: An EXAFS study

Energy Technology Data Exchange (ETDEWEB)

Provost, K; Bouvet-Muller, D; Michalowicz, A [ICMPE, UMR 7182 CNRS-Universite Paris 12, 94320 Thiais (France); Crauste-Manciet, S [Laboratoire de Pharmacie Galenique, Universite Paris Descartes, 75006 Paris (France); Olivi, L; Vlaic, G, E-mail: provost@univ-paris12.f [EXAFS Beamline, ELETTRA, Sincrotone Trieste, 34012 Basovizza, Trieste (Italy)

2009-11-15

We characterized the structures in solution of carboplatin and oxaliplatin degradation products in presence of a large excess of methionine (Met). The reaction of carboplatin leads to the formation of cis-Pt(Met){sub 2} while, in the case of oxaliplatin, methionine displaces only the oxalate ligand to form Pt(diaminocyclohexane)(Met).

Effects of sucrose on rFVIIa aggregation and methionine oxidation

DEFF Research Database (Denmark)

Soenderkaer, Susanne; Carpenter, John F; van de Weert, Marco

2004-01-01

The aim of this study was to characterize the effects of sucrose on the stability of recombinant factor VIIa (rFVIIa), with special emphasis on aggregation and methionine oxidation, as well as to investigate the impact of various environmental conditions on the rFVIIa conformation. The stability...... of rFVIIa was studied at pH 5. Aggregation was monitored using size exclusion high-performance liquid chromatography (SE-HPLC), whereas formation of methionine oxidation products was measured by reversed-phase high-performance liquid chromatography (RP-HPLC). Fourier transform infrared (FTIR...... the protein's surface, which shifts the protein molecular population away from expanded aggregation competent species and toward the compact native state, is thought to account for these observations. rFVIIa is sensitive to methionine oxidation; two mono-oxidized and one di-oxidized product were formed upon...

Ferulic acid depletion by cultured soybean seedlings under action of glucose and methionine

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Herrig Vanessa

2000-01-01

Full Text Available Cultured soybean seedlings were used to investigate how glucose or methionine influenced depletion of ferulic acid. Three-day-old seedlings were grown in hydroponic solution containing ferulic acid plus glucose or methionine, and the level of the phenolic acid were monitored in the nutrient culture. The results showed that ferulic acid depletion was more rapid in the presence of those compounds. After 6 h, the increase caused by glucose (0.01 and 0.05 mM was more pronounced than methionine in the same concentrations. On the other hand, methionine (0.1 and 0.2 mM increased depletion more significantly than glucose. Results suggested that both compounds might to increase the allelopathic effects of ferulic acid in the seedlings.

HAEM SYNTHASE AND COBALT PORPHYRIN SYNTHASE IN VARIOUS MICRO-ORGANISMS.

Science.gov (United States)

PORRA, R J; ROSS, B D

1965-03-01

1. The preparation of a crude extract of Clostridium tetanomorphum containing cobalt porphyrin synthase but little haem-synthase activity is described. 2. The properties of cobalt porphyrin synthase in the clostridial extracts is compared with the properties of a haem synthase present in crude extracts of the yeast Torulopsis utilis. 3. Cobalt porphyrin synthase in extracts of C. tetanomorphum inserts Co(2+) ions into the following dicarboxylic porphyrins in descending order of rate of insertion: meso-, deutero- and proto-porphyrins. Esterification renders meso- and deutero-porphyrins inactive as substrates. Neither the tetracarboxylic (coproporphyrin III) nor the octacarboxylic (uroporphyrin III) compounds are converted into cobalt porphyrins by the extract, but the non-enzymic incorporation of Co(2+) ions into these two porphyrins is rapid. These extracts are unable to insert Mn(2+), Zn(2+), Mg(2+) or Cu(2+) ions into mesoporphyrin. 4. Crude extracts of T. utilis readily insert both Co(2+) and Fe(2+) ions into deutero-, meso, and proto-porphyrins. Unlike the extracts of C. tetanomorphum, these preparations catalyse the insertion of Co(2+) ions into deuteroporphyrin more rapidly than into mesoporphyrin. This parallels the formation of haems by the T. utilis extract. 5. Cobalt porphyrin synthase is present in the particulate fraction of the extracts of C. tetanomorphum but requires a heat-stable factor present in the soluble fraction. This soluble factor can be replaced by GSH. 6. Cobalt porphyrin synthase in the clostridial extract is inhibited by iodoacetamide and to a smaller extent by p-chloromercuribenzoate and N-ethylmaleimide. The haem synthases of T. utilis and Micrococcus denitrificans are also inhibited by various thiol reagents.

Mechanism of oxidation of L-methionine by iron(III)-1,10 ...

Indian Academy of Sciences (India)

Unknown

Abstract. Kinetics and mechanism of oxidation of L-methionine by iron(III)–1,10- phenanthroline complex have been studied in perchloric acid medium. The reaction is first order each in iron(III) and methionine. Increase in [phenanthroline] increases the rate while increase in [HClO4] decreases it. While the reactive species ...

DNA-Mediated Cyclic GMP-AMP Synthase-Dependent and -Independent Regulation of Innate Immune Responses.

Science.gov (United States)

Motani, Kou; Ito, Shinji; Nagata, Shigekazu

2015-05-15

Cytoplasmic DNA activates cyclic GMP-AMP synthase (cGAS) to produce cyclic 2'-5'3'-5'GMP-AMP dinucleotide (2'5 'cGAMP). The binding of 2'5'cGAMP to an adaptor protein, stimulator of IFN genes (STING), activates a transcription factor, IFN regulatory factor 3, leading to the induction of IFN and chemokine gene expression. In this study, we found that the 2'5'cGAMP-dependent STING activation induced highly upregulated CXCL10 gene expression. Formation of a distinct STING dimer, which was detected by native PAGE, was induced by 2'5'cGAMP, but not 3'-5'3'-5'cGAMP. Analysis of DNase II(-/-) mice, which constitutively produce IFN-β and CXCL10, showed the accumulation of 2'5'cGAMP in their fetal livers and spleens, suggesting that the undigested DNA accumulating in DNase II(-/-) cells may have leaked from the lysosomes into the cytoplasm. The DNase II(-/-) mouse embryonic fibroblasts produced 2'5'cGAMP in a cGAS-dependent manner during apoptotic cell engulfment. However, cGAS deficiency did not impair the STING-dependent upregulation of CXCL10 in DNase II(-/-) mouse embryonic fibroblasts that was induced by apoptotic cell engulfment or DNA lipofection. These results suggest the involvement of a cGAS-independent additional DNA sensor(s) that induces the STING-dependent activation of innate immunity. Copyright © 2015 by The American Association of Immunologists, Inc.

Abnormal maternal biomarkers of homocysteine and methionine ...

African Journals Online (AJOL)

Rabah M. Shawky

2017-09-15

Sep 15, 2017 ... homocysteine and methionine metabolism are altered among non pregnant women who ..... groups as regards history of smoking, exposure to environmental ..... anomalies from 1950 to 1994: an international perspective.

Activation of Nrf2 is required for up-regulation of the π class of glutathione S-transferase in rat primary hepatocytes with L-methionine starvation.

Science.gov (United States)

Lin, Ai-Hsuan; Chen, Haw-Wen; Liu, Cheng-Tze; Tsai, Chia-Wen; Lii, Chong-Kuei

2012-07-04

Numerous genes expression is regulated in response to amino acid shortage, which helps organisms adapt to amino acid limitation. The expression of the π class of glutathione (GSH) S-transferase (GSTP), a highly inducible phase II detoxification enzyme, is regulated mainly by activates activating protein 1 (AP-1) binding to the enhancer I of GSTP (GPEI). Here we show the critical role of nuclear factor erythroid-2-related factor 2 (Nrf2) in up-regulating GSTP gene transcription. Primary rat hepatocytes were cultured in a methionine-restricted medium, and immunoblotting and RT-PCR analyses showed that methionine restriction time-dependently increased GSTP protein and mRNA expression over a 48 h period. Nrf2 translocation to the nucleus, nuclear proteins binding to GPEI, and antioxidant response element (ARE) luciferase reporter activity were increased by methionine restriction as well as by l-buthionine sulfoximine (BSO), a GSH synthesis inhibitor. Transfection with Nrf2 siRNA knocked down Nrf2 expression and reversed the methionine-induced GSTP expression and GPEI binding activity. Chromatin immunoprecipitation assay confirmed the binding of Nrf2 to the GPEI. Phosphorylation of extracellular signal-regulated kinase 2 (ERK2) was increased in methionine-restricted and BSO-treated cells. ERK2 siRNA abolished methionine restriction-induced Nrf2 nuclear translocation, GPEI binding activity, ARE-luciferase reporter activity, and GSTP expression. Our results suggest that the up-regulation of GSTP gene transcription in response to methionine restriction likely occurs via the ERK-Nrf2-GPEI signaling pathway.

[11C] Methionine as PET radiopharmaceutical produced at CDTN/CNEN

International Nuclear Information System (INIS)

Silveira, Marina B.; Ferreira, Soraya Z.; Carvalho, Tiago F.; Silva, Juliana B. da

2013-01-01

Carbon-11 ( 11 C) is an attractive radionuclide used in positron emission tomography (PET) since carbon is a ubiquitous element in biomolecules. Positron emitter-labeled amino acids are being widely used as indicators of tumor activity due to enhanced expression of amino acid transporter systems in cancer cells. L-[Methyl-( 11 C)] Methionine or [ 11 C]Methionine is being used in neuro-oncology and, unlike 2-[ 18 F]fluoro-2-deoxy-D-glucose ( 18 FDG), gives more contrast images and improves brain tumor diagnosis. The aim of this work was to develop the synthesis and quality control of [ 11 C]Methionine at the Radiopharmaceuticals Research and Production Facility (UPPR) of CDTN/CNEN. The synthesis of [ 11 C] Methionine was performed using two Sep-Pak tC18 plus cartridges one as solid support for the 11 C-methylation of the precursor L-homocysteine thiolactone hydrochloride and another for purification. The pH, radionuclidic identity and purity, residual solvents, radiochemical and chemical purity of the final product were evaluated as described on the European Pharmacopoeia 7.0 monograph. Total synthesis time was 18 minutes, the radiochemical yield was approximately 15% (non-decay corrected) and radiochemical purity was greater than 95%. [ 11 C]Methionine was successfully synthesized at CDTN using the described procedures and complied with quality requirements. Due to the rapid growth of oncologic PET scans in last decade, 11 C labelling holds great promises in the next few years with the application of other tracers beyond 18 FDG. This pioneering work of UPPR/CDTN represents a response to the demands of a growing nuclear medicine in the country focused on achieving better diagnostic imaging. (author)

Technical Note: Methionine, a precursor of methane in living plants

Science.gov (United States)

Lenhart, K.; Althoff, F.; Greule, M.; Keppler, F.

2015-03-01

When terrestrial plants were identified as producers of the greenhouse gas methane, much discussion and debate ensued not only about their contribution to the global methane budget but also with regard to the validity of the observation itself. Although the phenomenon has now become more accepted for both living and dead plants, the mechanism of methane formation in living plants remains to be elucidated and its precursor compounds to be identified. We made use of stable isotope techniques to verify the in vivo formation of methane, and, in order to identify the carbon precursor, 13C positionally labeled organic compounds were employed. Here we show that the amino acid L-methionine acts as a methane precursor in living plants. Employing 13C-labeled methionine clearly identified the sulfur-bound methyl group of methionine as a carbon precursor of methane released from lavender (Lavandula angustifolia). Furthermore, when lavender plants were stressed physically, methane release rates and the stable carbon isotope values of the emitted methane greatly increased. Our results provide additional support that plants possess a mechanism for methane production and suggest that methionine might play an important role in the formation of methane in living plants, particularly under stress conditions.

Optimization of ATP synthase function in mitochondria and chloroplasts via the adenylate kinase equilibrium

Directory of Open Access Journals (Sweden)

Abir U Igamberdiev

2015-01-01

Full Text Available The bulk of ATP synthesis in plants is performed by ATP synthase, the main bioenergetics engine of cells, operating both in mitochondria and in chloroplasts. The reaction mechanism of ATP synthase has been studied in detail for over half a century; however, its optimal performance depends also on the steady delivery of ATP synthase substrates and the removal of its products. For mitochondrial ATP synthase, we analyze here the provision of stable conditions for (i the supply of ADP and Mg2+, supported by adenylate kinase (AK equilibrium in the intermembrane space, (ii the supply of phosphate via membrane transporter in symport with H+, and (iii the conditions of outflow of ATP by adenylate transporter carrying out the exchange of free adenylates. We also show that, in chloroplasts, AK equilibrates adenylates and governs Mg2+ contents in the stroma, optimizing ATP synthase and Calvin cycle operation, and affecting the import of inorganic phosphate in exchange with triose phosphates. It is argued that chemiosmosis is not the sole component of ATP synthase performance, which also depends on AK-mediated equilibrium of adenylates and Mg2+, adenylate transport and phosphate release and supply.

Safety of methionine, a novel biopesticide, to adult and larval honey bees (Apis mellifera L.).

Science.gov (United States)

Weeks, Emma N I; Schmehl, Daniel R; Baniszewski, Julie; Tomé, Hudson V V; Cuda, James P; Ellis, James D; Stevens, Bruce R

2018-03-01

Methionine is an essential/indispensible amino acid nutrient required by adult and larval honey bees (Apis mellifera L. [Hymenoptera: Apidae]). Bees are unable to rear broods on pollen deficient in methionine, and reportedly behaviorally avoid collecting pollen or nectar from florets deficient in methioinine. In contrast, it has been demonstrated that methionine is toxic to certain pest insects; thus it has been proposed as an effective biopesticide. As an ecofriendly integrated pest management agent, methionine boasts a novel mode of action differentiating it from conventional pesticides, while providing non-target safety. Pesticides that minimize collateral effects on bees are desirable, given the economic and ecological concerns about honey bee health. The aim of the present study was to assess the potential impact of the biopesticide methionine on non-target adult and larval honey bees. Acute contact adult toxicology bioassays, oral adult assessments and chronic larval toxicity assessments were performed as per U.S. Environmental Protection Agency (EPA) requirements. Our results demonstrated that methionine fits the U.S. EPA category of practically nontoxic (i.e. lethal dose to 50% mortality or LD 50 > 11µg/bee) to adult honey bees. The contact LD 50 was > 25µg/bee and the oral LD 50 was > 100µg/bee. Mortality was observed in larval bees that ingested DL-methionine (effective concentration to 50% mortality or EC 50 560µg/bee). Therefore, we conclude that methionine poses little threat to the health of the honey bee, due to unlikely exposure at concentrations shown to elicit toxic effects. Copyright © 2017 Elsevier Inc. All rights reserved.

HERBAL METHIONINE (METHIOREP® IMPROVES GROWTH PERFORMANCE OF BROILER CHICKENS WITHOUT AFFECTING CARCASS CHARACTERISTICS AND BLOOD INDICES

Directory of Open Access Journals (Sweden)

O.J. Makinde

2017-05-01

Full Text Available Methiorep®, an herbal methionine premix, which is reported to contain herbal ingredients that mimic the activity of Methionine such as SAMe (S-Adenosyl Methionine and phosphatidyl choline, have recently introduced to Nigeria animal feed industry. An experiment was conducted with 120, one-week-old broilers to evaluate the effect of herbal methionine (methiorep® as substitute for synthetic methionine on growth performance of broiler chickens. Five isocaloric and isonitrogenous diets were formulated and Diet 1 (control, comprised of 0.25% methionine (NRC, 1994 while diet 2, 3, 4 and 5 comprised of 25%, 50%, 75% and 100% Methiorep® as substitute for methionine in the diets. The birds were randomly allocated to five experimental treatments, each treatment was replicated three times with eight birds per pen in a completely randomized design. The study lasted 49-days. The results of growth performance revealed that body weight gain, average feed intake and feed conversion ratio at both starter and finisher phases were not  influenced by dietary treatments (P>0.05. However cost per kg feed decreased as the level of Methiorep® increased in the diets (P0.05 by the dietary treatments. It was concluded that Methiorep® can completely substitute for Methionine in the diets of broiler chickens without adverse effect on growth performance, blood profiles and carcass yield of birds.

Elimination of remaining undifferentiated induced pluripotent stem cells in the process of human cardiac cell sheet fabrication using a methionine-free culture condition.

Science.gov (United States)

Matsuura, Katsuhisa; Kodama, Fumiko; Sugiyama, Kasumi; Shimizu, Tatsuya; Hagiwara, Nobuhisa; Okano, Teruo

2015-03-01

Cardiac tissue engineering is a promising method for regenerative medicine. Although we have developed human cardiac cell sheets by integration of cell sheet-based tissue engineering and scalable bioreactor culture, the risk of contamination by induced pluripotent stem (iPS) cells in cardiac cell sheets remains unresolved. In the present study, we established a novel culture method to fabricate human cardiac cell sheets with a decreased risk of iPS cell contamination while maintaining viabilities of iPS cell-derived cells, including cardiomyocytes and fibroblasts, using a methionine-free culture condition. When cultured in the methionine-free condition, human iPS cells did not survive without feeder cells and could not proliferate or form colonies on feeder cells or in coculture with cells for cardiac cell sheet fabrication. When iPS cell-derived cells after the cardiac differentiation were transiently cultured in the methionine-free condition, gene expression of OCT3/4 and NANOG was downregulated significantly compared with that in the standard culture condition. Furthermore, in fabricated cardiac cell sheets, spontaneous and synchronous beating was observed in the whole area while maintaining or upregulating the expression of various cardiac and extracellular matrix genes. These findings suggest that human iPS cells are methionine dependent and a methionine-free culture condition for cardiac cell sheet fabrication might reduce the risk of iPS cell contamination.

Methionine supplementation influences melanin-based plumage colouration in Eurasian kestrel, Falco tinnunculus, nestlings.

Science.gov (United States)

Parejo, Deseada; Silva, Nadia

2009-11-01

The extent to which the expression of melanin-based plumage colouration in birds is genetically or environmentally determined is controversial. Here, we performed a between-nest design supplementation with either the sulphur amino acid dl-methionine or with water to investigate the importance of the non-genetic component of melanin-based plumage colouration in the Eurasian kestrel, Falco tinnunculus. Methionine affects growth and immunity, thus we aimed to modify nestling growth and immunity before feather development. Then, we measured the effect of the experiment on colouration of two melanin-based plumage patches of nestling kestrels. We found that methionine slowed down nestling growth through treatment administration and that nestlings compensated by speeding up their growth later. We did not find any effects of methionine on nestling immunity (i.e. lymphocyte counts, natural antibody levels or complement-mediated immunity). Effects on growth seemed to be mirrored by changes in nestling colouration in the two sexes: methionine-nestlings showed less intense brown plumage on their backs compared with control nestlings. These results provide support for a non-genetic determination of a melanin-based plumage patch in the two sexes of nestling kestrels.

Radiation stability of methionine-35S and selenomethionine-75Se

International Nuclear Information System (INIS)

Galateanu, I.; Lungu, V.V.; Viorel, D.

1976-01-01

The radiation stability of methionine- 35 S and selenomethionine 75 Se was investigated using the methods of thin-layer chromatography, gas chromatography and ESR. Radiation decomposition of methionine- 35 S mainly consists in an oxidation process and in the release of volatile products. The ESR-spectra of irradiated DL-methionine indicated a strong localization of the unpaired electrons on sulfur atoms. Radiation damage to selenomethionine- 75 Se as a function of radiation dose proved an increased stability of this compound and its radiation decomposition consists in the formation of oxidized products and by direct rupture of the selenium bounds accompanied by the formation of volatile compounds like CH 3 SEH and SeH 2 . The self-radiolysis of the aqueous solution of selenomethionine- 75 Se during its storage in air leads, however, to a lower decomposition rate which consists in the release of inorganic selenium and in an oxidation process. (author)

[11C] Methionine as PET radiopharmaceutical produced at CDTN/CNEN

Energy Technology Data Exchange (ETDEWEB)

Silveira, Marina B.; Ferreira, Soraya Z.; Carvalho, Tiago F.; Silva, Juliana B. da, E-mail: mbs@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Unidade de Pesquisa e Producao de Radiofarmacos

2013-07-01

Carbon-11 ({sup 11}C) is an attractive radionuclide used in positron emission tomography (PET) since carbon is a ubiquitous element in biomolecules. Positron emitter-labeled amino acids are being widely used as indicators of tumor activity due to enhanced expression of amino acid transporter systems in cancer cells. L-[Methyl-({sup 11}C)] Methionine or [{sup 11}C]Methionine is being used in neuro-oncology and, unlike 2-[{sup 18}F]fluoro-2-deoxy-D-glucose ({sup 18}FDG), gives more contrast images and improves brain tumor diagnosis. The aim of this work was to develop the synthesis and quality control of [{sup 11}C]Methionine at the Radiopharmaceuticals Research and Production Facility (UPPR) of CDTN/CNEN. The synthesis of [{sup 11}C] Methionine was performed using two Sep-Pak tC18 plus cartridges one as solid support for the {sup 11}C-methylation of the precursor L-homocysteine thiolactone hydrochloride and another for purification. The pH, radionuclidic identity and purity, residual solvents, radiochemical and chemical purity of the final product were evaluated as described on the European Pharmacopoeia 7.0 monograph. Total synthesis time was 18 minutes, the radiochemical yield was approximately 15% (non-decay corrected) and radiochemical purity was greater than 95%. [{sup 11}C]Methionine was successfully synthesized at CDTN using the described procedures and complied with quality requirements. Due to the rapid growth of oncologic PET scans in last decade, {sup 11}C labelling holds great promises in the next few years with the application of other tracers beyond {sup 18}FDG. This pioneering work of UPPR/CDTN represents a response to the demands of a growing nuclear medicine in the country focused on achieving better diagnostic imaging. (author)

The relative contribution of genes operating in the S-methylmethionine cycle to methionine metabolism in Arabidopsis seeds.

Science.gov (United States)

Cohen, Hagai; Salmon, Asaf; Tietel, Zipora; Hacham, Yael; Amir, Rachel

2017-05-01

Enzymes operating in the S -methylmethionine cycle make a differential contribution to methionine synthesis in seeds. In addition, mutual effects exist between the S -methylmethionine cycle and the aspartate family pathway in seeds. Methionine, a sulfur-containing amino acid, is a key metabolite in plant cells. The previous lines of evidence proposed that the S-methylmethionine (SMM) cycle contributes to methionine synthesis in seeds where methionine that is produced in non-seed tissues is converted to SMM and then transported via the phloem into the seeds. However, the relative regulatory roles of the S-methyltransferases operating within this cycle in seeds are yet to be fully understood. In the current study, we generated transgenic Arabidopsis seeds with altered expression of three HOMOCYSTEINE S-METHYLTRANSFERASEs (HMTs) and METHIONINE S-METHYLTRANSFERASE (MMT), and profiled them for transcript and metabolic changes. The results revealed that AtHMT1 and AtHMT3, but not AtHMT2 and AtMMT, are the predominant enzymes operating in seeds as altered expression of these two genes affected the levels of methionine and SMM in transgenic seeds. Their manipulations resulted in adapted expression level of genes participating in methionine synthesis through the SMM and aspartate family pathways. Taken together, our findings provide new insights into the regulatory roles of the SMM cycle and the mutual effects existing between the two methionine biosynthesis pathways, highlighting the complexity of the metabolism of methionine and SMM in seeds.

Influence of protein level and supplemental methionine in practical rations for young endangered masked bobwhite quail

Science.gov (United States)

Serafin, J.A.

1982-01-01

A study was conducted to examine the protein requirement of young endangered masked Bobwhite quail (Colinus virginianus ridgwayi). Five practical starting rations containing 24 to 32% protein were fed alone and supplemented with methionine for 5 weeks. Supplemental methionine significantly improved growth of quail fed diets containing 24 and 26% protein. Increasing the protein level improved growth of quail fed unsupplemented diets but did not do so when diets contained supplemental methionine. A methionine-supplemented ration containing 24% protein appeared adequate for supporting rapid growth of masked Bobwhite quail.

Utilization of supplemental methionine sources by primary cultures of chick hepatocytes

International Nuclear Information System (INIS)

Dibner, J.J.

1983-01-01

Utilization of 2-hydroxy-4-(methylthio) butanoic acid (HMB) as a substrate for protein synthesis was studied by using primary cultures of chick liver cells. Cultures were prepared by enzymatic dissociation of livers from week old Hubbard broiler chicks and were maintained for 4 days under nonproliferative conditions. Hepatocyte differentiation was verified by using dexamethasone induction of tyrosine aminotransferase activity. Conversion of [14C]HMB to L-methionine was shown by chromatographic analysis of hepatocyte protein hydrolysate and incorporation into protein was proven by cycloheximide inhibition of synthesis. When incorporation of HMB was compared to that of DL-methionine (DLM) equimolar quantities of the two sources were found in liver cell protein. These results support, at a cellular level, the conclusion that HMB and DLM are biochemically equivalent sources of methionine for protein synthesis

Absorption of l-methionine from the human small intestine

Science.gov (United States)

Schedl, Harold P.; Pierce, Charles E.; Rider, Alan; Clifton, James A.

1968-01-01

Absorption of L-methionine was measured in all parts of the human small intestine using transintestinal intubation and perfusion. In four normal subjects, adsorption was higher in the proximal than in the distal intestine. In two patients with nontropical sprue in relapse, there was a proximal zone of low absorption with higher absorption distally. In all parts of the small intestine, absorption showed rate-limiting kinetics as methionine concentration was increased. In normal subjects, the proximal Km (Michaelis constant) was more than 3 times higher than the distal, which suggests a difference in transport mechanisms between the two segments. PMID:12066784

A novel mechanism of sulfur transfer catalyzed by O-acetylhomoserine sulfhydrylase in the methionine-biosynthetic pathway of Wolinella succinogenes

Energy Technology Data Exchange (ETDEWEB)

Tran, Timothy H. [Cornell University, Ithaca, New York 14853-1301 (United States); Krishnamoorthy, Kalyanaraman; Begley, Tadhg P., E-mail: begley@tamu.edu [Texas A& M University, College Station, TX 77842 (United States); Ealick, Steven E., E-mail: begley@tamu.edu [Cornell University, Ithaca, New York 14853-1301 (United States)

2011-10-01

MetY is the first reported structure of an O-acetylhomoserine sulfhydrylase that utilizes a protein thiocarboxylate intermediate as the sulfur source in a novel methionine-biosynthetic pathway instead of catalyzing a direct sulfhydrylation reaction. O-Acetylhomoserine sulfhydrylase (OAHS) is a pyridoxal 5′-phosphate (PLP) dependent sulfide-utilizing enzyme in the l-cysteine and l-methionine biosynthetic pathways of various enteric bacteria and fungi. OAHS catalyzes the conversion of O-acetylhomoserine to homocysteine using sulfide in a process known as direct sulfhydrylation. However, the source of the sulfur has not been identified and no structures of OAHS have been reported in the literature. Here, the crystal structure of Wolinella succinogenes OAHS (MetY) determined at 2.2 Å resolution is reported. MetY crystallized in space group C2 with two monomers in the asymmetric unit. Size-exclusion chromatography, dynamic light scattering and crystal packing indicate that the biological unit is a tetramer in solution. This is further supported by the crystal structure, in which a tetramer is formed using a combination of noncrystallographic and crystallographic twofold axes. A search for structurally homologous proteins revealed that MetY has the same fold as cystathionine γ-lyase and methionine γ-lyase. The active sites of these enzymes, which are also PLP-dependent, share a high degree of structural similarity, suggesting that MetY belongs to the γ-elimination subclass of the Cys/Met metabolism PLP-dependent family of enzymes. The structure of MetY, together with biochemical data, provides insight into the mechanism of sulfur transfer to a small molecule via a protein thiocarboxylate intermediate.

Tissue methionine cycle activity and homocysteine metabolism in female rats: impact of dietary methionine and folate plus choline

NARCIS (Netherlands)

Wilson, F.A.; Borne, van den J.J.G.C.; Calder, A.G.; O'Kennedy, N.; Holtrop, G.; Rees, W.D.; Lobley, G.E.

2009-01-01

Impaired transfer of methyl groups via the methionine cycle leads to plasma hyperhomocysteinemia. The tissue sources of plasma homocysteine in vivo have not been quantified nor whether hyperhomocysteinemia is due to increased entry or decreased removal. These issues were addressed in female rats

Independent and additive effects of glutamic acid and methionine on yeast longevity.

Science.gov (United States)

Wu, Ziyun; Song, Lixia; Liu, Shao Quan; Huang, Dejian

2013-01-01

It is established that glucose restriction extends yeast chronological and replicative lifespan, but little is known about the influence of amino acids on yeast lifespan, although some amino acids were reported to delay aging in rodents. Here we show that amino acid composition greatly alters yeast chronological lifespan. We found that non-essential amino acids (to yeast) methionine and glutamic acid had the most significant impact on yeast chronological lifespan extension, restriction of methionine and/or increase of glutamic acid led to longevity that was not the result of low acetic acid production and acidification in aging media. Remarkably, low methionine, high glutamic acid and glucose restriction additively and independently extended yeast lifespan, which could not be further extended by buffering the medium (pH 6.0). Our preliminary findings using yeasts with gene deletion demonstrate that glutamic acid addition, methionine and glucose restriction prompt yeast longevity through distinct mechanisms. This study may help to fill a gap in yeast model for the fast developing view that nutrient balance is a critical factor to extend lifespan.

Monoterpene synthases from common sage (Salvia officinalis)

Energy Technology Data Exchange (ETDEWEB)

Croteau, Rodney Bruce (Pullman, WA); Wise, Mitchell Lynn (Pullman, WA); Katahira, Eva Joy (Pullman, WA); Savage, Thomas Jonathan (Christchurch 5, NZ)

1999-01-01

cDNAs encoding (+)-bornyl diphosphate synthase, 1,8-cineole synthase and (+)-sabinene synthase from common sage (Salvia officinalis) have been isolated and sequenced, and the corresponding amino acid sequences has been determined. Accordingly, isolated DNA sequences (SEQ ID No:1; SEQ ID No:3 and SEQ ID No:5) are provided which code for the expression of (+)-bornyl diphosphate synthase (SEQ ID No:2), 1,8-cineole synthase (SEQ ID No:4) and (+)-sabinene synthase SEQ ID No:6), respectively, from sage (Salvia officinalis). In other aspects, replicable recombinant cloning vehicles are provided which code for (+)-bornyl diphosphate synthase, 1,8-cineole synthase or (+)-sabinene synthase, or for a base sequence sufficiently complementary to at least a portion of (+)-bornyl diphosphate synthase, 1,8-cineole synthase or (+)-sabinene synthase DNA or RNA to enable hybridization therewith. In yet other aspects, modified host cells are provided that have been transformed, transfected, infected and/or injected with a recombinant cloning vehicle and/or DNA sequence encoding (+)-bornyl diphosphate synthase, 1,8-cineole synthase or (+)-sabinene synthase. Thus, systems and methods are provided for the recombinant expression of the aforementioned recombinant monoterpene synthases that may be used to facilitate their production, isolation and purification in significant amounts. Recombinant (+)-bornyl diphosphate synthase, 1,8-cineole synthase and (+)-sabinene synthase may be used to obtain expression or enhanced expression of (+)-bornyl diphosphate synthase, 1,8-cineole synthase and (+)-sabinene synthase in plants in order to enhance the production of monoterpenoids, or may be otherwise employed for the regulation or expression of (+)-bornyl diphosphate synthase, 1,8-cineole synthase and (+)-sabinene synthase, or the production of their products.

Crystal structure of a new homochiral one-dimensional zincophosphate containing l-methionine

Directory of Open Access Journals (Sweden)

Nadjet Chouat

2015-07-01

Full Text Available catena-Poly[[(l-methionine-κOzinc]-μ3-(hydrogen phosphato-κ3O:O′:O′′], [Zn{PO3(OH}(C5H11NO2S]n, a new one-dimensional homochiral zincophosphate, was hydrothermally synthesized using l-methionine as a structure-directing agent. The compound consists of a network of ZnO4 and (HOPO3 tetrahedra that form ladder-like chains of edge-fused Zn2P2O4 rings propagating parallel to [100]. The chains are decorated on each side by zwitterionic l-methionine ligands, which interact with the inorganic framework via Zn—O coordination bonds. The structure displays interchain N—H...O and O—H...S hydrogen bonds.

The molecular motor F-ATP synthase is targeted by the tumoricidal protein HAMLET.

Science.gov (United States)

Ho, James; Sielaff, Hendrik; Nadeem, Aftab; Svanborg, Catharina; Grüber, Gerhard

2015-05-22

HAMLET (human alpha-lactalbumin made lethal to tumor cells) interacts with multiple tumor cell compartments, affecting cell morphology, metabolism, proteasome function, chromatin structure and viability. This study investigated if these diverse effects of HAMLET might be caused, in part, by a direct effect on the ATP synthase and a resulting reduction in cellular ATP levels. A dose-dependent reduction in cellular ATP levels was detected in A549 lung carcinoma cells, and by confocal microscopy, co-localization of HAMLET with the nucleotide-binding subunits α (non-catalytic) and β (catalytic) of the energy converting F1F0 ATP synthase was detected. As shown by fluorescence correlation spectroscopy, HAMLET binds to the F1 domain of the F1F0 ATP synthase with a dissociation constant (KD) of 20.5μM. Increasing concentrations of the tumoricidal protein HAMLET added to the enzymatically active α3β3γ complex of the F-ATP synthase lowered its ATPase activity, demonstrating that HAMLET binding to the F-ATP synthase effects the catalysis of this molecular motor. Single-molecule analysis was applied to study HAMLET-α3β3γ complex interaction. Whereas the α3β3γ complex of the F-ATP synthase rotated in a counterclockwise direction with a mean rotational rate of 3.8±0.7s(-1), no rotation could be observed in the presence of bound HAMLET. Our findings suggest that direct effects of HAMLET on the F-ATP synthase may inhibit ATP-dependent cellular processes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Feed efficiency of diets with different energy and protein concentrations supplemented with methionine in laying quails

Science.gov (United States)

Ratriyanto, A.; Indreswari, R.; Nuhriawangsa, A. M. P.; Purwanti, E.

2018-03-01

The study was conducted to evaluate the feed efficiency of quail diets containing different concentrations of metabolizable energy (ME) and crude protein (CP) with constant ratio and supplemented with methionine. Four hundred laying quails (Coturnix coturnix japonica) were randomly assigned to four experimental diets in a 2×2 factorial arrangement. Each dietary treatment used 5 replicates of 20 quails. Two basal diets were formulated to contain 2,800 kcal kg-1 ME and 18.7% CP (High ME-CP) and 2,600 kcal kg-1 ME and 17.3% CP (Low ME-CP). Each basal diet was supplemented with 0 and 0.12% methionine. The High ME-CP diets generated lower feed consumption but higher egg mass and feed efficiency (Pprotein efficiency ratio (PHigh ME-CP supplemented with methionine resulted the highest feed efficiency followed by the Low ME-CP supplemented with methionine, while both High ME-CP and Low ME-CP without methionine supplementation resulted the lowest feed efficiency (PHigh ME-CP supplemented with 0.12% methionine provided benefit to improve the feed efficiency in laying quails.

Individual radiation response of parotid glands investigated by dynamic 11C-methionine PET

International Nuclear Information System (INIS)

Buus, Simon; Grau, Cai; Munk, Ole Lajord; Rodell, Anders; Jensen, Kenneth; Mouridsen, Kim; Keiding, Susanne

2006-01-01

Background and Purpose: Previously, we showed that the net metabolic clearance of 11 C-methionine of the parotid gland, K, calculated from dynamic 11 C-methionine PET, can be used as a measure of parotid gland function. The aim of this study was to investigate by dynamic 11 C-methionine PET the individual radiation dose response relationship of parotid glands in head and neck cancer patients. Patients and methods: Twelve head and neck cancer patients were examined by dynamic 11 C-methionine PET after radiotherapy. Parametric images of K were generated, co-registered and compared voxel-by-voxel with the 3D radiation dose plan within the parotid gland to assess the individual radiation dose-function relationship. Results: In each patient, voxel-values of K decreased with increasing radiation dose. Population based analysis showed a sigmoid dose response relationship of parotid gland, from which we estimated a threshold radiation dose of 16 Gy and a mean TD 5 of 30 Gy. TD 5 ranged from 7 to 50 Gy in the group of patients. Conclusions: Individual radiation dose response of parotid glands can be measured by dynamic 11 C-methionine PET. The dose response analysis revealed a sigmoid relationship, a threshold radiation dose of 16 Gy, and a mean TD 5 of 30 Gy

Effects and mechanism of acid rain on plant chloroplast ATP synthase.

Science.gov (United States)

Sun, Jingwen; Hu, Huiqing; Li, Yueli; Wang, Lihong; Zhou, Qing; Huang, Xiaohua

2016-09-01

Acid rain can directly or indirectly affect plant physiological functions, especially photosynthesis. The enzyme ATP synthase is the key in photosynthetic energy conversion, and thus, it affects plant photosynthesis. To clarify the mechanism by which acid rain affects photosynthesis, we studied the effects of acid rain on plant growth, photosynthesis, chloroplast ATP synthase activity and gene expression, chloroplast ultrastructure, intracellular H(+) level, and water content of rice seedlings. Acid rain at pH 4.5 remained the chloroplast structure unchanged but increased the expression of six chloroplast ATP synthase subunits, promoted chloroplast ATP synthase activity, and increased photosynthesis and plant growth. Acid rain at pH 4.0 or less decreased leaf water content, destroyed chloroplast structure, inhibited the expression of six chloroplast ATP synthase subunits, decreased chloroplast ATP synthase activity, and reduced photosynthesis and plant growth. In conclusion, acid rain affected the chloroplast ultrastructure, chloroplast ATPase transcription and activity, and P n by changing the acidity in the cells, and thus influencing the plant growth and development. Finally, the effects of simulated acid rain on the test indices were found to be dose-dependent.

Endothelium-dependent relaxation of rat aorta to a histamine H3 agonist is reduced by inhibitors of nitric oxide synthase, guanylate cyclase and Na+,K+-ATPase

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D. M. Djuric

1996-01-01

Full Text Available The possible involvement of different effector systems (nitric oxide synthase, guanylate cyclase, β-adrenergic and muscarinic cholinergic receptors, cyclooxygenase and lipoxygenase, and Na+,K+-ATPase was evaluated in a histamine H3 receptor agonist-induced ((Rα-methylhistamine, (Rα-MeHA endothelium-dependent rat aorta relaxation assay. (Rα-MeHA (0.1 nM – 0.01 mM relaxed endothelium-dependent rat aorta, with a pD2 value of 8.22 ± 0.06, compared with a pD2 value of 7.98 ± 0.02 caused by histamine (50% and 70% relaxation, respectively. The effect of (Rα-MeHA (0.1 nM – 0.01 mM was competitively antagonized by thioperamide (1, 10 and 30 nM (pA2 = 9.21 ± 0.40; slope = 1.03 ± 0.35 but it was unaffected by pyrilamine (100 nM, cimetidine (1 μM, atropine (10 μM, propranolol (1 μM, indomethacin (10 μM or nordthydroguaiaretic acid (0.1 mM. Inhibitors of nitric oxide synthase, L-NG-monomethylarginine (L-NMMA, 10 μM and NG-nitro-L-arginine methylester (L-NOARG, 10 μM inhibited the relaxation effect of (Rα-MeHA, by approximately 52% and 70%, respectively. This inhibitory effect of L-NMMA was partially reversed by L-arginine (10 μM. Methylene blue (10 μM and ouabain (10 μM inhibited relaxation (Rα-MeHA-induced by approximately 50% and 90%, respectively. The products of cyclooxygenase and lipoxygenase are not involved in (Rα-MeHA-induced endothelium-dependent rat aorta relaxation nor are the muscarinic cholinergic and β-adrenergic receptors. The results also suggest the involvement of NO synthase, guanylate cyclase and Na+,K+-ATPase in (Rα-MeHA-induced endothelium-dependent rat aorta relaxation.

A NOVEL S-ADENOSYL-L-METHIONINE: ARSENIC (III) METHYLTRANSFERASE FROM RAT LIVER CYTOSOL

Science.gov (United States)

A Novel S-Adenosyl-L-methionine: Arsenic(III) Methyltransferase from Rat Liver CytosolShan Lin, Qing Shi, F. Brent Nix, Miroslav Styblo, Melinda A. Beck, Karen M. Herbin-Davis, Larry L. Hall, Josef B. Simeonsson, and David J. Thomas S-adenosyl-L-methionine (AdoMet): ar...

The effect of the oxidation state of the folate standard on the results of the simultaneous radioassay of serum folate and cobalamin

International Nuclear Information System (INIS)

Lindemans, J.; Kapel, J. van

1981-01-01

The authors have compared a commercial radioisotope dilution assay using pteroylglutamic acid as a standard and a non-commercial assay using L-methyl-tetrahydrofolate as a standard. The iodinated tracer folate was the same in both methods. Both assays measure folate and colabamin simultaneously, which gave the opportunity to discuss also the results of the cobalamin assay. (Auth.)

One-step synthesis of an {sup 18}F-labeled boron-derived methionine analog. A substitute for {sup 11}C-methionine?

Energy Technology Data Exchange (ETDEWEB)

Liu, Zhen; Lan, Xiaoli [Huazhong University of Science and Technology, Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Wuhan (China); Huazhong University of Science and Technology, Hubei Key Laboratory of Molecular Imaging, Union Hospital, Tongji Medical College, Wuhan (China); Ehlerding, Emily B. [University of Wisconsin - Madison, Department of Medical Physics, Madison, WI (United States); Cai, Weibo [University of Wisconsin - Madison, Department of Medical Physics, Madison, WI (United States); University of Wisconsin - Madison, Department of Radiology, Madison, WI (United States); University of Wisconsin - Madison, Carbone Cancer Center, Madison, WI (United States)

2018-04-15

Amino acid-based tracers have been extensively investigated for positron emission tomography (PET) imaging of brain tumors, and {sup 11}C-methionine ({sup 11}C-MET) is one of the most extensively investigated. However, widespread clinical use of {sup 11}C-MET is challenging due to the short half-life of {sup 11}C and low radiolabeling yield. In this issue of the European Journal of Nuclear Medicine and Molecular Imaging, Yang and colleagues report an {sup 18}F-labeled boron-derived methionine analog, {sup 18}F-B-MET, as a potential substitute for {sup 11}C-MET in PET imaging of glioma. The push-button synthesis, highly efficient radiolabeling, and good imaging performance in glioma models make this tracer a promising candidate for future clinical translation. (orig.)

Electron addition to alkyl cobalamins, coenzyme B/sub 12/ and vitamin B/sub 12/. [Gamma radiation

Energy Technology Data Exchange (ETDEWEB)

Rao, D N.R.; Symons, M C.R. [Leicester Univ. (UK). Dept. of Chemistry

1983-01-01

Exposure of dilute solutions of methyl and ethyl cobalamins and coenzyme B/sub 12/ in dilute solutions (D/sub 2/O+CD/sub 3/OD) to /sup 60/Co ..gamma..-rays at 77 K gave a single broad feature in the free-spin region assigned to electron-capture species with the excess electron largely confined to a ..pi..* corrin orbital. On warming above 77 K the methyl derivative gave a novel species with spectral features characteristic of an unpaired electron in the Co(dsub(x/sup 2/-y/sup 2/)) orbital. The other two substrates gave spectra due to Cosup(II)Bsub(12r) both on warming and after photolyses with visible light. The acetyl derivative gave an electron-capture species whose e.s.r. spectrum was characteristic of an electron in the Co(dsub(z/sup 2/)) orbital, which on warming above 77 K changed to the normal Cosup(II)Bsub(12r) spectrum. The cyano derivative (vitamin B/sub 12/) gave electron addition into the Co(dsub(z/sup 2/)) orbital, as evidenced by the large hyperfine coupling to /sup 13/C from /sup 13/CN ligands. On annealing, cyanide ions were lost irreversibly, Bsub(12r) being detected by e.s.r. spectroscopy. In contrast, the dicyano derivative on electron addition at 77 K gave a species containing only one /sup 13/CN ligand. Hence in this case one CN/sup -/ ligand was lost at 77 K, with no return of the dimethylbenzimidazole ligand. These results are discussed in terms of a new mechanism for electron-addition to alkyl cobalamins.

Two Distinct Aerobic Methionine Salvage Pathways Generate Volatile Methanethiol in Rhodopseudomonas palustris

Science.gov (United States)

Miller, Anthony R.; North, Justin A.; Wildenthal, John A.

2018-01-01

ABSTRACT 5′-Methyl-thioadenosine (MTA) is a dead-end, sulfur-containing metabolite and cellular inhibitor that arises from S-adenosyl-l-methionine-dependent reactions. Recent studies have indicated that there are diverse bacterial methionine salvage pathways (MSPs) for MTA detoxification and sulfur salvage. Here, via a combination of gene deletions and directed metabolite detection studies, we report that under aerobic conditions the facultatively anaerobic bacterium Rhodopseudomonas palustris employs both an MTA-isoprenoid shunt identical to that previously described in Rhodospirillum rubrum and a second novel MSP, both of which generate a methanethiol intermediate. The additional R. palustris aerobic MSP, a dihydroxyacetone phosphate (DHAP)-methanethiol shunt, initially converts MTA to 2-(methylthio)ethanol and DHAP. This is identical to the initial steps of the recently reported anaerobic ethylene-forming MSP, the DHAP-ethylene shunt. The aerobic DHAP-methanethiol shunt then further metabolizes 2-(methylthio)ethanol to methanethiol, which can be directly utilized by O-acetyl-l-homoserine sulfhydrylase to regenerate methionine. This is in contrast to the anaerobic DHAP-ethylene shunt, which metabolizes 2-(methylthio)ethanol to ethylene and an unknown organo-sulfur intermediate, revealing functional diversity in MSPs utilizing a 2-(methylthio)ethanol intermediate. When MTA was fed to aerobically growing cells, the rate of volatile methanethiol release was constant irrespective of the presence of sulfate, suggesting a general housekeeping function for these MSPs up through the methanethiol production step. Methanethiol and dimethyl sulfide (DMS), two of the most important compounds of the global sulfur cycle, appear to arise not only from marine ecosystems but from terrestrial ones as well. These results reveal a possible route by which methanethiol might be biologically produced in soil and freshwater environments. PMID:29636438

Methionine Metabolites in Patients With Sepsis.

Science.gov (United States)

Wexler, Orren; Gough, Michael S; Morgan, Mary Anne M; Mack, Cynthia M; Apostolakos, Michael J; Doolin, Kathleen P; Mooney, Robert A; Arning, Erland; Bottiglieri, Teodoro; Pietropaoli, Anthony P

2018-01-01

Sepsis is characterized by microvascular dysfunction and thrombophilia. Several methionine metabolites may be relevant to this sepsis pathophysiology. S-adenosylmethionine (SAM) serves as the methyl donor for trans-methylation reactions. S-adenosylhomocysteine (SAH) is the by-product of these reactions and serves as the precursor to homocysteine. Relationships between plasma total homocysteine concentrations (tHcy) and vascular disease and thrombosis are firmly established. We hypothesized that SAM, SAH, and tHcy levels are elevated in patients with sepsis and associated with mortality. This was a combined case-control and prospective cohort study consisting of 109 patients with sepsis and 50 control participants without acute illness. The study was conducted in the medical and surgical intensive care units of the University of Rochester Medical Center. Methionine, SAM, SAH, and tHcy concentrations were compared in patients with sepsis versus control participants and in sepsis survivors versus nonsurvivors. Patients with sepsis had significantly higher plasma SAM and SAH concentrations than control participants (SAM: 164 [107-227] vs73 [59-87 nM], P sepsis patients compared to healthy control participants (4 [2-6]) vs 7 [5-9] μM; P = .04). In multivariable analysis, quartiles of SAM, SAH, and tHcy were independently associated with sepsis ( P = .006, P = .05, and P Sepsis nonsurvivors had significantly higher plasma SAM and SAH concentrations than survivors (SAM: 223 [125-260] vs 136 [96-187] nM; P = .01; SAH: 139 [81-197] vs 86 [55-130] nM, P = .006). Plasma tHcy levels were similar in survivors vs nonsurvivors. The associations between SAM or SAH and hospital mortality were no longer significant after adjusting for renal dysfunction. Methionine metabolite concentrations are abnormal in sepsis and linked with clinical outcomes. Further study is required to determine whether these abnormalities have pathophysiologic significance.

Role of methionine on epigenetic modification of DNA methylation and gene expression in animals

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Naifeng Zhang

2018-03-01

Full Text Available DNA methylation is one of the main epigenetic phenomena affecting gene expression. It is an important mechanism for the development of embryo, growth and health of animals. As a key nutritional factor limiting the synthesis of protein, methionine serves as the precursor of S-adenosylmethionine (SAM in the hepatic one-carbon metabolism. The dietary fluctuation of methionine content can alter the levels of metabolic substrates in one-carbon metabolism, e.g., the SAM, S-adenosylhomocysteine (SAH, and change the expression of genes related to the growth and health of animals by DNA methylation reactions. The ratio of SAM to SAH is called ‘methylation index’ but it should be carefully explained because the complexity of methylation reaction. Alterations of methylation in a specific cytosine-guanine (CpG site, rather than the whole promoter region, might be enough to change gene expression. Aberrant methionine cycle may provoke molecular changes of one-carbon metabolism that results in deregulation of cellular hemostasis and health problems. The importance of DNA methylation has been underscored but the mechanisms of methionine affecting DNA methylation are poorly understood. Nutritional epigenomics provides a promising insight into the targeting epigenetic changes in animals from a nutritional standpoint, which will deepen and expand our understanding of genes, molecules, tissues, and animals in which methionine alteration influences DNA methylation and gene expression. Keywords: Epigenetics, Methionine, DNA methylation, Gene expression, Epigenetic modification

Influence of dietary protein and excess methionine on choline needs for young bobwhite quail

Science.gov (United States)

Serafin, J.A.

1982-01-01

Experiments were conducted with young Bobwhite quail (Colinus virginianus) to investigate the effect of differing dietary protein levels and nondetrimental amounts of excess methionine on choline needs. Growth and feed consumption of quail fed an adequate (27.3%) protein purified diet supplemented with 2000 mg/kg of choline were unaffected by increasing the level of excess methionine to 1.75%; however, greater amounts (2.0%, 2.25%) of excess methionine depressed growth (P less than .01), reduced feed consumption (P less than .01), and decreased feed utilization (P less than .05). Quail fed a purified diet containing 13.85% protein and 515 mg/kg of choline grew poorly. Growth was unaffected by additional choline in this diet. Growth was suboptimal among quail fed purified diets containing adequate or high (41.55%) levels of protein in which choline was limiting; however, a high level of protein did not in itself affect performance. Growth was improved by supplemental choline in these diets. Growth of quail fed purified diets with up to 1.35% excess methionine which were limiting (531 mg/kg) in choline was less than that of groups fed 2000 mg/kg of added dietary choline (P less than .01); however, excess methionine did not significantly influence growth of quail fed choline-deficient diets. These experiments indicate that neither high dietary protein nor excess methionine, fed at non-growth-depressing levels, increases dietary choline needs for young Bobwhite quail.

Puerarin activates endothelial nitric oxide synthase through estrogen receptor-dependent PI3-kinase and calcium-dependent AMP-activated protein kinase

International Nuclear Information System (INIS)

Hwang, Yong Pil; Kim, Hyung Gyun; Hien, Tran Thi; Jeong, Myung Ho; Jeong, Tae Cheon; Jeong, Hye Gwang

2011-01-01

The cardioprotective properties of puerarin, a natural product, have been attributed to the endothelial nitric oxide synthase (eNOS)-mediated production of nitric oxide (NO) in EA.hy926 endothelial cells. However, the mechanism by which puerarin activates eNOS remains unclear. In this study, we sought to identify the intracellular pathways underlying eNOS activation by puerarin. Puerarin induced the activating phosphorylation of eNOS on Ser1177 and the production of NO in EA.hy926 cells. Puerarin-induced eNOS phosphorylation required estrogen receptor (ER)-mediated phosphatidylinositol 3-kinase (PI3K)/Akt signaling and was reversed by AMP-activated protein kinase (AMPK) and calcium/calmodulin-dependent kinase II (CaMKII) inhibition. Importantly, puerarin inhibited the adhesion of tumor necrosis factor (TNF)-α-stimulated monocytes to endothelial cells and suppressed the TNF-α induced expression of intercellular cell adhesion molecule-1. Puerarin also inhibited the TNF-α-induced nuclear factor-κB activation, which was attenuated by pretreatment with N G -nitro-L-arginine methyl ester, a NOS inhibitor. These results indicate that puerarin stimulates eNOS phosphorylation and NO production via activation of an estrogen receptor-mediated PI3K/Akt- and CaMKII/AMPK-dependent pathway. Puerarin may be useful for the treatment or prevention of endothelial dysfunction associated with diabetes and cardiovascular disease. -- Highlights: ► Puerarin induced the phosphorylation of eNOS and the production of NO. ► Puerarin activated eNOS through ER-dependent PI3-kinase and Ca 2+ -dependent AMPK. ► Puerarin-induced NO was involved in the inhibition of NF-kB activation. ► Puerarin may help for prevention of vascular dysfunction and diabetes.

Seleno methionine-75 as a scanning agent for neuroblastoma

International Nuclear Information System (INIS)

Covington, E.E.; D'Angio, G.J.; Helson, L.; Romano, R.W.

1974-01-01

Neuroblastoma is a functioning tumor and patients with this tumor are known to excrete vanilmandelic acid and other degradation products of norepinephrine. It also accumulates and produces excess cystathionine for which methionine is a precursor in the normal anabolic pathway. This was the rationale for testing 75 Se-methionine as a possible scanning agent in patients with neuroblastoma. D'Angio et al reported the results of a preliminary investigation in which 3 of 4 patients with neuroblastoma, all with known metastases of the skull, had positive scans correctly localizing the disease. These preliminary data seemed encouraging, and further investigation was undertaken. The results are reported

Methionine-supplemented diet affects the expression of cardiovascular disease-related genes and increases inflammatory cytokines in mice heart and liver.

Science.gov (United States)

Aissa, Alexandre Ferro; Amaral, Catia Lira do; Venancio, Vinicius Paula; Machado, Carla da Silva; Hernandes, Lívia Cristina; Santos, Patrick Wellington da Silva; Curi, Rui; Bianchi, Maria de Lourdes Pires; Antunes, Lusânia Maria Greggi

2017-01-01

Some important environmental factors that influence the development of cardiovascular diseases (CVD) include tobacco, excess alcohol, and unhealthy diet. Methionine obtained from the diet participates in the synthesis of DNA, proteins, lipids and affects homocysteine levels, which is associated with the elevated risk for CVD development. Therefore, the aim of this study was to investigate the manner in which dietary methionine might affect cellular mechanisms underlying CVD occurrence. Swiss albino mice were fed either control (0.3% DL-methionine), methionine-supplemented (2% DL-methionine), or a methionine-deprived diet (0% DL-methionine) over a 10-week period. The parameters measured included plasma homocysteine concentrations, oxidative stress by reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio, levels of inflammatory cytokines IL-1ß, TNF-α, and IL-6, as well as expression of genes associated with CVD. The levels of apolipoprotein A5 (APOA5), a regulator of plasma triglycerides, were measured. The methionine-supplemented diet increased oxidative stress by lowering the GSH/GSSG ratio in heart tissues and decreased expression of the genes Apob, Ctgf, Serpinb2, Spp1, Il1b, and Sell, but elevated expression of Thbs4, Tgfb2, Ccr1, and Vegfa. Methionine-deprived diet reduced expression of Col3a1, Cdh5, Fabp3, Bax, and Hbegf and increased expression of Sell, Ccl5, Itga2, Birc3, Msr1, Bcl2a1a, Il1r2, and Selp. Methionine-deprived diet exerted pro-inflammatory consequences as evidenced by elevated levels of cytokines IL-1ß, TNF-α, and IL-6 noted in liver. Methionine-supplemented diet increased hepatic IL-6 and cardiac TNF-α. Both methionine supplementation and deprivation lowered hepatic levels of APOA5. In conclusion, data demonstrated that a methionine-supplemented diet modulated important biological processes associated with high risk of CVD development.

Investigation of the metal binding site in methionine aminopeptidase by density functional theory

DEFF Research Database (Denmark)

Jørgensen, Anne Techau; Norrby, Per-Ola; Liljefors, Tommy

2002-01-01

All methionine aminopeptidases exhibit the same conserved metal binding site. The structure of this site with either Co2+ ions or Zn2+ ions was investigated using density functional theory. The calculations showed that the structure of the site was not influenced by the identity of the metal ions....... This was the case for both of the systems studied; one based on the X-ray structure of the human methionine aminopeptidase type 2 (hMetAP-2) and the other based on the X-ray structure of the E. coli methionine aminopeptidase type 1 (eMetAP-1). Another important structural issue is the identity of the bridging...

Parameters of the labeling of mitogen-activated murine lymphocytes by [35S]methionine for two-dimensional gel electrophoresis. I

International Nuclear Information System (INIS)

Kettman, J.R.

1986-01-01

Labeling with [ 35 S]methionine at a high specific activity is essential to the facile preparation of 2-dimensional gel electrophoretograms with the analytical 2-dimensional charge-size separation procedure. Mitogen-activated T and B lymphocytes subjected to low methionine concentrations would not proceed through cell cycle. In the case of activated B lymphocytes, the use of fetal bovine serum, dialyzed to lower endogenous methionine concentrations, prevented B cell growth even in the presence of otherwise satisfactory levels of methionine. High concentrations of [ 35 S]methionine induced B cell death, apparently by radiation damage. Despite these problems, good radioautograms and radiofluorograms of 2D electrophoretograms could be prepared by labeling activated B or T cells in bulk with high specific activity [ 35 S]methionine. (Auth.)

Methionine supplementation in the productive efficiency, carcass ...

African Journals Online (AJOL)

The effect of dietary methionine supplementation at varying levels on the productive efficiency, carcass characteristics and economics of growing indigenous turkey was investigated. Four Isocaloric and Isonitrogenous diets were formulated. The diets were supplemented with 0.00%, 0.05%, 0.10%, and 0.15% respectively.

Fluoresence quenching of riboflavin in aqueous solution by methionin and cystein

International Nuclear Information System (INIS)

Droessler, P.; Holzer, W.; Penzkofer, A.; Hegemann, P.

2003-01-01

The fluorescence quantum distributions, fluorescence quantum yields, and fluorescence lifetimes of riboflavin in methanol, DMSO, water, and aqueous solutions of the sulphur atom containing amino acids methionin and cystein have been determined. In methanol, DMSO, and water (pH=4-8) only dynamic fluorescence reduction due to intersystem crossing and internal conversion is observed. In aqueous methionin solutions of pH=5.25-9 a pH independent static and dynamic fluorescence quenching occurs probably due to riboflavin anion-methionin cation pair formation. In aqueous cystein solutions (pH range from 4.15 to 9) the fluorescence quenching increases with rising pH due to cystein thiolate formation. The cystein thiol form present at low pH does not react with neutral riboflavin. Cystein thiolate present at high pH seems to react with neutral riboflavin causing riboflavin deprotonation (anion formation) by cystein thiolate reduction to the cystein thiol form

Bio-efficacy comparison of herbal-methionine and DL-methionine based on performance and blood parameters of broiler chickens

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Sheila Hadinia

2014-06-01

Full Text Available This study was conducted to compare the bio-efficacy of herbal methionine (H-Met relative to DL-methionine (DL-Met on 160 “Ross 308” broiler chickens. DL-Met and H-Met were added to the basal diet in eight experimental treatments with three and four concentrations respectively in starter, grower and finisher period. Blood parameters which were measured at 24 and 42 days of age consisted of: serum proteins (total protein, albumin and globulin, serum uric acid, serum fats (low density lipoprotein, high density lipoprotein, triglyceride and cholesterol and serum enzymes (alanine amino transaminase and aspartate amino transaminase. Completely randomized design, multi-exponential and multilinear regressions were used to determine bio-efficacy of H-Met in terms of performance and blood parameters of broilers. The results showed that supplemented methionine (Met sources had no significant effect on blood parameters at 24 day of age. At 42 day of age the amounts of globulin and serum high density lipoprotein (HDL increased with supplemented Met, (p < 0.05. Regression analysis revealed that H-Met was 55.00, 71.00, 78.00, 47.00, 58.00 and 73.00% as efficacious as DL-Met for body weight gain, feed intake, feed conversion ratio, albumin, globulin and high density lipoprotein criteria, respectively. The average of bio-efficacy of H-Met compared to DL-Met was 67.00% and 59.00% on average across performance criteria and blood criteria respectively and was 63.00% across these two criteria tested. The results of the present study indicated that H-Met can be administered as a new and a natural source of Met in poultry industry.

Proteomic Characterization of Armillaria mellea Reveals Oxidative Stress Response Mechanisms and Altered Secondary Metabolism Profiles

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Cassandra Collins

2017-09-01

Full Text Available Armillaria mellea is a major plant pathogen. Yet, the strategies the organism uses to infect susceptible species, degrade lignocellulose and other plant material and protect itself against plant defences and its own glycodegradative arsenal are largely unknown. Here, we use a combination of gel and MS-based proteomics to profile A. mellea under conditions of oxidative stress and changes in growth matrix. 2-DE and LC-MS/MS were used to investigate the response of A. mellea to H2O2 and menadione/FeCl3 exposure, respectively. Several proteins were detected with altered abundance in response to H2O2, but not menadione/FeCl3 (i.e., valosin-containing protein, indicating distinct responses to these different forms of oxidative stress. One protein, cobalamin-independent methionine synthase, demonstrated a common response in both conditions, which may be a marker for a more general stress response mechanism. Further changes to the A. mellea proteome were investigated using MS-based proteomics, which identified changes to putative secondary metabolism (SM enzymes upon growth in agar compared to liquid cultures. Metabolomic analyses revealed distinct profiles, highlighting the effect of growth matrix on SM production. This establishes robust methods by which to utilize comparative proteomics to characterize this important phytopathogen.

Acute Administration of Methionine Affects Performance of Swiss ...

African Journals Online (AJOL)

olayemitoyin

The effect of methionine on learning and memory in mice was investigated using Morris ... neurological disorders by excitotoxicity and ... Central cholinergic system plays a major role in ... acetylcholinesterase leads to increased levels of brain.

Nutritional levels of digestible methionine + cystine to brown-egg laying hens from 50 to 66 weeks of age

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Clauber Polese

2012-07-01

Full Text Available The objective of this study was to determine the requirement of digestible methionine + cystine of brown-eggs laying hens from 50 to 66 weeks age at the end of the first production cycle. The design was completely randomized, with 150 Brown Shaver hens, which were distributed in five treatments with six replications of five birds each. Birds received a basal diet with 2857 kcal/kg metabolizable energy and 15.97% crude protein, supplemented with 0.132; 0.174, 0.215, 0.256 and 0.298% DL-methionine (98%, in order to provide 0.572, 0.613, 0.653, 0.693 and 0.734% digestible methionine + cystine. The levels of digestible methionine + digestible cystine followed, respectively, the relations of 67, 72, 77, 81 and 86% with lysine fixed at 0.851%. Feed intake, methionine + cystine intake, feed conversion per dozen eggs, egg weigth and mass, percentage of egg components, internal egg quality and weight gain were evaluated. Methionine + cystine levels showed a quadratic effect on feed conversion per dozen eggs and egg weight, a linear effect on feed conversion per kilogram of eggs and percentage of albumen. There was also a positive linear effect on yolk percentage. The methionine + cystine requirement was estimated at 0.572%, corresponding to 682 mg of digestible methionine + cystine/bird/day.

Crystal structure and dimerization equilibria of PcoC, a methionine-rich copper resistance protein from Escherichia coli

Energy Technology Data Exchange (ETDEWEB)

Wernimont, A.K.; Huffman, D.L.; Finney, L.A.; Demeler, B.; O' Halloran, T.V.; Rosenzweig, A.C.

2010-03-08

PcoC is a soluble periplasmic protein encoded by the plasmid-born pco copper resistance operon of Escherichia coli. Like PcoA, a multicopper oxidase encoded in the same locus and its chromosomal homolog CueO, PcoC contains unusual methionine rich sequences. Although essential for copper resistance, the functions of PcoC, PcoA, and their conserved methionine-rich sequences are not known. Similar methionine motifs observed in eukaryotic copper transporters have been proposed to bind copper, but there are no precedents for such metal binding sites in structurally characterized proteins. The high-resolution structures of apo PcoC, determined for both the native and selenomethionine-containing proteins, reveal a seven-stranded barrel with the methionines unexpectedly housed on a solvent-exposed loop. Several potential metal-binding sites can be discerned by comparing the structures to spectroscopic data reported for copper-loaded PcoC. In the native structure, the methionine loop interacts with the same loop on a second molecule in the asymmetric unit. In the selenomethionine structure, the methionine loops are more exposed, forming hydrophobic patches on the protein surface. These two arrangements suggest that the methionine motifs might function in protein-protein interactions between PcoC molecules or with other methionine-rich proteins such as PcoA. Analytical ultracentrifugation data indicate that a weak monomer-dimer equilibrium exists in solution for the apo protein. Dimerization is significantly enhanced upon binding Cu(I) with a measured {Delta}({Delta}G{sup o}) {le} -8.0 kJ/mole, suggesting that copper might bind at the dimer interface.

Crystal growth and structure of L-methionine L-methioninium hydrogen maleate-a new NLO material

International Nuclear Information System (INIS)

Natarajan, Subramanian; Rajan Devi, Neelamagam; Britto Dhas, Sathiya Dhas Martin; Athimoolam, Shanmuganarayanan

2008-01-01

A new organic nonlinear optical (NLO) crystal from the amino acid family, viz., L-methionine L-methioninium hydrogen maleate (LMMM), has been grown by slow evaporation method from aqueous solution. Bulk crystals were grown using submerged seed solution method. The structure was elucidated using the single crystal x-ray diffraction data. The compound crystallized in the space group P2 1 and the unit cell contains a protonated L-methioninium cation and a zwitterionic methionine residue plus a maleate anion. The backbone conformation angles Ψ 1 and Ψ 2 are in cis and trans configurations for both the methionine and methioninium residues, respectively. Amino and carboxyl groups of the methioninium and methionine residues are connected through N-H...O hydrogen bonds leading to a ring R 2 2 (10) motif.

Methionine sulfoxide profiling of milk proteins to assess the influence of lipids on protein oxidation in milk.

Science.gov (United States)

Wüst, Johannes; Pischetsrieder, Monika

2016-06-15

Thermal treatment of milk and milk products leads to protein oxidation, mainly the formation of methionine sulfoxide. Reactive oxygen species, responsible for the oxidation, can be generated by Maillard reaction, autoxidation of sugars, or lipid peroxidation. The present study investigated the influence of milk fat on methionine oxidation in milk. For this purpose, quantitative methionine sulfoxide profiling of all ten methionine residues of β-lactoglobulin, α-lactalbumin, and αs1-casein was carried out by ultrahigh-performance liquid chromatography-electrospray ionization tandem mass spectrometry with scheduled multiple reaction monitoring (UHPLC-ESI-MS/MS-sMRM). Analysis of defatted and regular raw milk samples after heating for up to 8 min at 120 °C and analysis of ultrahigh-temperature milk samples with 0.1%, 1.5%, and 3.5% fat revealed that methionine oxidation of the five residues of the whey proteins and of residues M 123, M 135, and M 196 of αs1-casein was not affected or even suppressed in the presence of milk fat. Only the oxidation of residues M 54 and M 60 of αs1-casein was promoted by lipids. In evaporated milk samples, formation of methionine sulfoxide was hardly influenced by the fat content of the samples. Thus, it can be concluded that lipid oxidation products are not the major cause of methionine oxidation in milk.

Puerarin activates endothelial nitric oxide synthase through estrogen receptor-dependent PI3-kinase and calcium-dependent AMP-activated protein kinase

Energy Technology Data Exchange (ETDEWEB)

Hwang, Yong Pil; Kim, Hyung Gyun [Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon (Korea, Republic of); Hien, Tran Thi [College of Pharmacy, Chosun University, Gwangju (Korea, Republic of); Jeong, Myung Ho [Heart Research Center, Chonnam National University Hospital, Gwangju (Korea, Republic of); Jeong, Tae Cheon, E-mail: taecheon@ynu.ac.kr [College of Pharmacy, Yeungnam University, Gyungsan (Korea, Republic of); Jeong, Hye Gwang, E-mail: hgjeong@cnu.ac.kr [Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon (Korea, Republic of)

2011-11-15

The cardioprotective properties of puerarin, a natural product, have been attributed to the endothelial nitric oxide synthase (eNOS)-mediated production of nitric oxide (NO) in EA.hy926 endothelial cells. However, the mechanism by which puerarin activates eNOS remains unclear. In this study, we sought to identify the intracellular pathways underlying eNOS activation by puerarin. Puerarin induced the activating phosphorylation of eNOS on Ser1177 and the production of NO in EA.hy926 cells. Puerarin-induced eNOS phosphorylation required estrogen receptor (ER)-mediated phosphatidylinositol 3-kinase (PI3K)/Akt signaling and was reversed by AMP-activated protein kinase (AMPK) and calcium/calmodulin-dependent kinase II (CaMKII) inhibition. Importantly, puerarin inhibited the adhesion of tumor necrosis factor (TNF)-{alpha}-stimulated monocytes to endothelial cells and suppressed the TNF-{alpha} induced expression of intercellular cell adhesion molecule-1. Puerarin also inhibited the TNF-{alpha}-induced nuclear factor-{kappa}B activation, which was attenuated by pretreatment with N{sup G}-nitro-L-arginine methyl ester, a NOS inhibitor. These results indicate that puerarin stimulates eNOS phosphorylation and NO production via activation of an estrogen receptor-mediated PI3K/Akt- and CaMKII/AMPK-dependent pathway. Puerarin may be useful for the treatment or prevention of endothelial dysfunction associated with diabetes and cardiovascular disease. -- Highlights: Black-Right-Pointing-Pointer Puerarin induced the phosphorylation of eNOS and the production of NO. Black-Right-Pointing-Pointer Puerarin activated eNOS through ER-dependent PI3-kinase and Ca{sup 2+}-dependent AMPK. Black-Right-Pointing-Pointer Puerarin-induced NO was involved in the inhibition of NF-kB activation. Black-Right-Pointing-Pointer Puerarin may help for prevention of vascular dysfunction and diabetes.

Secretion Of Methionine By Microorganisms Associated With ...

African Journals Online (AJOL)

methionine were secreted after 96 hours and 72 hours respectively by the lactobacilli and Leuconostoc sp. Since lactic acid bacteria are micro-aerophilic, it is suggested that lactic acid bacteria (the two lactobacilli and Leuconostoc sp.), which are the major organisms involved in cassava fermentation for garri production, ...

An Arabidopsis callose synthase

DEFF Research Database (Denmark)

Ostergaard, Lars; Petersen, Morten; Mattsson, Ole

2002-01-01

in the Arabidopsis mpk4 mutant which exhibits systemic acquired resistance (SAR), elevated beta-1,3-glucan synthase activity, and increased callose levels. In addition, AtGsl5 is a likely target of salicylic acid (SA)-dependent SAR, since AtGsl5 mRNA accumulation is induced by SA in wild-type plants, while...... expression of the nahG salicylate hydroxylase reduces AtGsl5 mRNA levels in the mpk4 mutant. These results indicate that AtGsl5 is likely involved in callose synthesis in flowering tissues and in the mpk4 mutant....

Oxidation of Methionine by Tripropylammonium Fluorochromate-A Kinetic and Mechanistic Study

Directory of Open Access Journals (Sweden)

S. Sheik Mansoor

2011-01-01

Full Text Available The kinetics of oxidation of methionine (Met by tripropylammonium fluorochromate (TriPAFC has been studied in the presence of chloroacetic acid in aqueous acetic acid medium. The reaction is first order with respect to methionine, TriPAFC and acid. The reaction rate has been determined at different temperatures and activation parameters calculated. With an increase in the amount of acetic acid in its aqueous mixture, the rate increases. The reaction does not induce polymerization of acrylonitrile. A suitable mechanism has been proposed.

Studies on the Active Site of Deacetoxycephalosporin C Synthase

NARCIS (Netherlands)

Lloyd, Matthew D.; Lee, Hwei-Jen; Harlos, Karl; Zhang, Zhi-Hong; Baldwin, Jack E.; Schofield, Christopher J.; Charnock, John M.; Garner, C. David; Hara, Takane; Terwisscha van Scheltinga, Anke C.; Valegård, Karin; Viklund, Jenny A.C.; Hajdu, Janos; Andersson, Inger; Danielsson, Åke; Bhikhabhai, Rama

1999-01-01

The Fe(II) and 2-oxoglutarate-dependent dioxygenase deacetoxycephalosporin C synthase (DAOCS) from Streptomyces clavuligerus was expressed at ca 25% of total soluble protein in Escherichia coli and purified by an efficient large-scale procedure. Purified protein catalysed the conversions of

Influence of Methionine Supplementation on Nicotine Teratogenicity ...

African Journals Online (AJOL)

Human and animal studies have shown that maternal tobacco smoking during pregnancy adversely affects pre and postnatal growth and increases the risk of fetal mortality. The aim of the present study was to determine the toxicity of nicotine and protective effect of methionine on the toxic effects of nicotine. Pregnant ...

GNMT Expression Increases Hepatic Folate Contents and Folate-Dependent Methionine Synthase-Mediated Homocysteine Remethylation

OpenAIRE

Wang, Yi-Cheng; Chen, Yi-Ming; Lin, Yan-Jun; Liu, Shih-Ping; Chiang, En-Pei Isabel

2011-01-01

Glycine N-methyltransferase (GNMT) is a major hepatic enzyme that converts S-adenosylmethionine to S-adenosylhomocysteine while generating sarcosine from glycine, hence it can regulate mediating methyl group availability in mammalian cells. GNMT is also a major hepatic folate binding protein that binds to, and, subsequently, may be inhibited by 5-methyltetrafolate. GNMT is commonly diminished in human hepatoma; yet its role in cellular folate metabolism, in tumorigenesis and antifolate therap...

Processivity and Subcellular Localization of Glycogen Synthase Depend on a Non-catalytic High Affinity Glycogen-binding Site*

OpenAIRE

Díaz, Adelaida; Martínez-Pons, Carlos; Fita, Ignacio; Ferrer, Juan C.; Guinovart, Joan J.

2011-01-01

Glycogen synthase, a central enzyme in glucose metabolism, catalyzes the successive addition of α-1,4-linked glucose residues to the non-reducing end of a growing glycogen molecule. A non-catalytic glycogen-binding site, identified by x-ray crystallography on the surface of the glycogen synthase from the archaeon Pyrococcus abyssi, has been found to be functionally conserved in the eukaryotic enzymes. The disruption of this binding site in both the archaeal and the human muscle glycogen synth...

Functional loss of two ceramide synthases elicits autophagy-dependent lifespan extension in C. elegans

DEFF Research Database (Denmark)

Mosbech, Mai-Britt; Kruse, Rikke; Harvald, Eva Bang

2013-01-01

Ceramide and its metabolites constitute a diverse group of lipids, which play important roles as structural entities of biological membranes as well as regulators of cellular growth, differentiation, and development. The C. elegans genome comprises three ceramide synthase genes; hyl-1, hyl-2...... that hyl-1;lagr-1 animals display reduced feeding, increased resistance to heat, and reduced reproduction. Collectively, our data suggest that specific sphingolipids produced by different ceramide synthases have opposing roles in determination of C. elegans lifespan. We propose that loss of HYL-1 and LAGR......, and lagr-1. HYL-1 function is required for synthesis of ceramides and sphingolipids containing very long acyl-chains (≥C24), while HYL-2 is required for synthesis of ceramides and sphingolipids containing shorter acyl-chains (≤C22). Here we show that functional loss of HYL-2 decreases lifespan, while loss...

Milder clinical and biochemical phenotypes associated with the c.482G>A (p.Arg161Gln) pathogenic variant in cobalamin C disease: Implications for management and screening.

Science.gov (United States)

Almannai, Mohammed; Marom, Ronit; Divin, Kristian; Scaglia, Fernando; Sutton, V Reid; Craigen, William J; Lee, Brendan; Burrage, Lindsay C; Graham, Brett H

2017-09-01

Cobalamin C disease is a multisystemic disease with variable manifestations and age of onset. Genotype-phenotype correlations are well-recognized in this disorder. Here, we present a large cohort of individuals with cobalamin C disease, several of whom are heterozygous for the c.482G>A pathogenic variant (p.Arg161Gln). We compared clinical characteristics of individuals with this pathogenic variant to those who do not have this variant. To our knowledge, this study represents the largest single cohort of individuals with the c.482G>A (p.Arg161Gln) pathogenic variant. A retrospective chart review of 27 individuals from 21 families with cobalamin C disease who are followed at our facility was conducted. 13 individuals (48%) are compound heterozygous with the c.482G>A (p.Arg161Gln) on one allele and a second pathogenic variant on the other allele. Individuals with the c.482G>A (p.Arg161Gln) pathogenic variant had later onset of symptoms and easier metabolic control. Moreover, they had milder biochemical abnormalities at presentation which likely contributed to the observation that 4 individuals (31%) in this group were missed by newborn screening. The c.482G>A (p.Arg161Gln) pathogenic variant is associated with milder disease. These individuals may not receive a timely diagnosis as they may not be identified on newborn screening or because of unrecognized, late onset symptoms. Despite the milder presentation, significant complications can occur, especially if treatment is delayed. Copyright © 2017 Elsevier Inc. All rights reserved.

Quantitative proteomics reveals the mechanism and consequence of gliotoxin-mediated dysregulation of the methionine cycle in Aspergillus niger

OpenAIRE

Manzanares-Miralles, Lara; Bayram, Ozgur; Sarikaya-Bayram, Ozlem; Smith, Elizabeth B.; Dolan, Stephen K.; Jones, Gary W.; Doyle, Sean

2016-01-01

Gliotoxin (GT) is a redox-active metabolite, produced by Aspergillus fumigatus,which inhibits the growth of other fungi. Here we demonstrate how Aspergillus niger responds to GT exposure. Quantitative proteomics revealed that GT dysregulated the abundance of 378 proteins including those involved in methionine metabolism and induced de novo abundance of two S-adenosylmethionine (SAM)-dependent methyltransferases. Increased abundance of enzymes S-adenosylhomocysteinase (p = 0.0018) ...

Predicting the catalytic sites of isopenicillin N synthase (IPNS ...

African Journals Online (AJOL)

Isopenicillin N synthase (IPNS) related Non-haem iron-dependent oxygenases and oxidases (NHIDOX) demonstrated a striking structural conservativeness, even with low protein sequence homology. It is evident that these enzymes have an architecturally similar catalytic centre with active ligands lining the reactive pocket.

Loss of Ceramide Synthases Elicits a PHA-4/FoxA-, SKN-1-, and Autophagy-Dependent Lifespan Extension in C. elegans

DEFF Research Database (Denmark)

Jensen, Mai-Britt Mosbech; Færgeman, Nils J.; Ejsing, Christer S.

2011-01-01

, these lipid species are recognized as bioactive signalling molecules involved in regulation of cell growth, differentiation, senescence, and apoptosis, and thus a delicate equilibrium between the levels of these interconvertible lipid species underlies the balance between cell survival and death. The C....... elegans genome comprises three ceramide synthase genes; hyl-1, hyl-2, and lagr-1. Here we show that functional loss of HYL-1 and LAGR-1 depletes 43:1;3 sphingolipids and extends lifespan in a PHA-4-, SKN-1-, and ATG-12-dependent manner. The transcription factors PHA-4 and SKN-1 as well as ATG-12, which...

Acute Administration of Methionine Affects Performance of Swiss ...

African Journals Online (AJOL)

olayemitoyin

biogenic amines. The effect of methionine on learning and memory in mice was investigated using Morris water maze .... normal brain. This is in a bid to proffer long-term .... A short transfer latency on Day 2 was taken as a ..... age Children.

Sulfur amino acid metabolism in doxorubicin-resistant breast cancer cells

International Nuclear Information System (INIS)

Ryu, Chang Seon; Kwak, Hui Chan; Lee, Kye Sook; Kang, Keon Wook; Oh, Soo Jin; Lee, Ki Ho; Kim, Hwan Mook; Ma, Jin Yeul; Kim, Sang Kyum

2011-01-01

Although methionine dependency is a phenotypic characteristic of tumor cells, it remains to be determined whether changes in sulfur amino acid metabolism occur in cancer cells resistant to chemotherapeutic medications. We compared expression/activity of sulfur amino acid metabolizing enzymes and cellular levels of sulfur amino acids and their metabolites between normal MCF-7 cells and doxorubicin-resistant MCF-7 (MCF-7/Adr) cells. The S-adenosylmethionine/S-adenosylhomocysteine ratio, an index of transmethylation potential, in MCF-7/Adr cells decreased to ∼ 10% relative to that in MCF-7 cells, which may have resulted from down-regulation of S-adenosylhomocysteine hydrolase. Expression of homocysteine-clearing enzymes, such as cystathionine beta-synthase, methionine synthase/methylene tetrahydrofolate reductase, and betaine homocysteine methyltransferase, was up-regulated in MCF-7/Adr cells, suggesting that acquiring doxorubicin resistance attenuated methionine-dependence and activated transsulfuration from methionine to cysteine. Homocysteine was similar, which is associated with a balance between the increased expressions of homocysteine-clearing enzymes and decreased extracellular homocysteine. Despite an elevation in cysteine, cellular GSH decreased in MCF-7/Adr cells, which was attributed to over-efflux of GSH into the medium and down-regulation of the GSH synthesis enzyme. Consequently, MCF-7/Adr cells were more sensitive to the oxidative stress induced by bleomycin and menadione than MCF-7 cells. In conclusion, our results suggest that regulating sulfur amino acid metabolism may be a possible therapeutic target for chemoresistant cancer cells. These results warrant further investigations to determine the role of sulfur amino acid metabolism in acquiring anticancer drug resistance in cancer cells using chemical and biological regulators involved in sulfur amino acid metabolism. - Research highlights: → MCF-7/Adr cells showed decreases in cellular GSH

Vitamin B-12

Science.gov (United States)

Vitamin B-12 is a cofactor for 2 enzymes. In the cytoplasm, methionine synthase requires vitamin B-12 in the form of methylcobalamin and catalyzes the conversion of homocysteine to methionine by transfer of a methyl group from methyltetrahydrofolate.This enzyme links the methylation pathway through ...

l-Methionine anti-biofilm activity against Pseudomonas aeruginosa is enhanced by the cystic fibrosis transmembrane conductance regulator potentiator, ivacaftor.

Science.gov (United States)

Cho, Do-Yeon; Lim, Dong-Jin; Mackey, Calvin; Weeks, Christopher G; Peña Garcia, Jaime A; Skinner, Daniel; Grayson, Jessica W; Hill, Harrison S; Alexander, David K; Zhang, Shaoyan; Woodworth, Bradford A

2018-05-01

Biofilms may contribute to refractory chronic rhinosinusitis (CRS), as they lead to antibiotic resistance and failure of effective clinical treatment. l-Methionine is an amino acid with reported biofilm-inhibiting properties. Ivacaftor is a cystic fibrosis transmembrane conductance regulator (CFTR) potentiator with mild antimicrobial activity via inhibition of bacterial DNA gyrase and topoisomerase IV. The objective of this study was to evaluate whether co-treatment with ivacaftor and l-methionine can reduce the formation of Pseudomonas aeruginosa biofilms. P aeruginosa (PAO-1 strain) biofilms were studied in the presence of l-methionine and/or ivacaftor. For static biofilm assays, PAO-1 was cultured in a 48-well plate for 72 hours with stepwise combinations of these agents. Relative biofilm inhibitions were measured according to optical density of crystal violet stain at 590 nm. Live/dead assays (BacTiter-Glo™ assay, Promega) were imaged with laser scanning confocal microscopy. An agar diffusion test was used to confirm antibacterial effects of the drugs. l-Methionine (0.5 μM) significantly reduced PAO-1 biofilm mass (32.4 ± 18.0%; n = 4; p l-methionine (two-way analysis of variane, p = 0.0415) compared with corresponding concentrations of l-methionine alone. Ivacaftor enhanced the anti-biofilm activity of l-methionine against the PAO-1 strain of P aeruginosa. Further studies evaluating the efficacy of ivacaftor/l-methionine combinations for P aeruginosa sinusitis are planned. © 2018 ARS-AAOA, LLC.

Benzalacetone Synthase

Directory of Open Access Journals (Sweden)

Ikuro eAbe

2012-03-01

Full Text Available Benzalacetone synthase, from the medicinal plant Rheum palmatum (Polygonaceae (RpBAS, is a plant-specific chalcone synthase (CHS superfamily of type III polyketide synthase (PKS. RpBAS catalyzes the one-step, decarboxylative condensation of 4-coumaroyl-CoA with malonyl-CoA to produce the C6-C4 benzalacetone scaffold. The X-ray crystal structures of RpBAS confirmed that the diketide-forming activity is attributable to the characteristic substitution of the conserved active-site "gatekeeper" Phe with Leu. Furthermore, the crystal structures suggested that RpBAS employs novel catalytic machinery for the thioester bond cleavage of the enzyme-bound diketide intermediate and the final decarboxylation reaction to produce benzalacetone. Finally, by exploiting the remarkable substrate tolerance and catalytic versatility of RpBAS, precursor-directed biosynthesis efficiently generated chemically and structurally divergent, unnatural novel polyketide scaffolds. These findings provided a structural basis for the functional diversity of the type III PKS enzymes.

Effects of methionine supplementation on the expression of protein deposition-related genes in acute heat stress-exposed broilers.

Directory of Open Access Journals (Sweden)

Ana Paula Del Vesco

Full Text Available The objective of this study was to evaluate the effect of heat stress and methionine supplementation on the gene expression of insulin-like growth factor I (IGF-I, growth hormone receptor (GHR, phosphatidylinositol 3-kinase, and regulatory 1 (PI3KR1 in the liver, as well as the expression of the atrogin 1 and cathepsin L2 (CTSL2 genes in the breast muscle of broilers. Broilers from 1-21 and 22-42 days of age were divided into three treatments related to methionine supplementation as follows: without methionine supplementation (MD, recommended level of methionine (DL1, and excess supplementation of methionine (DL2. The animals were either maintained at a thermal comfort temperature or exposed to heat stress (HS (38°C for 24 hours, starting on day 20 or day 41 for experiments 1 and 2, respectively. The heat stress increased the body temperature at both ages. Starter period: The HS animals presented increased plasma creatinine content (P<0.0001 and the highest CTSL2 gene expression (P<0.0001. The methionine supplementation increased the IGF-I (P = 0.0144 and GHR (P = 0.0011 gene expression and decreased the CTSL2 (P = 0.0004 and atrogin 1 (P = 0.0012 gene expression. Grower period: Significant effects for the interaction between supplementation and environment were observed for GHR (P = 0.0252 and CTSL2 (P = 0.0011 gene expression. The highest GHR expression was observed in animals that remained in thermal comfort on the DL2 diet, and the lowest expression occurred in the HS animals fed the MD diet. For CTSL2, the HS animals fed the MD diet presented the highest CTSL2 gene expression, and the lowest expression was observed in the animals maintained at thermal comfort on DL1 and DL2 diets. Only methionine supplementation had effect on atrogin-1 gene expression (P<0.0001, with higher methionine content in the diet lower atrogin-1 gene expression was observed. Our results suggest that heat stress induces greater protein degradation and that

Paracellular transport of avidin saturated or not with biotinylated cobalamin through Caco-2 cell epithelium monolayer.

Science.gov (United States)

Guy, M; Pons, L; Namour, F; de Nonancourt, M; Michalski, J C; Hatier, R; Guéant, J L

2001-01-01

The cationic charge of molecules may promote their uptake across epithelia, which are rich in brush border anionic sites. The transport of unsaturated avidin and avidin saturated with a biotinylated compound was investigated across Caco-2 adenocarcinoma cell with fetal enterocyte phenotype. The unsaturated avidin and avidin saturated with either biotin or a biotinyl-cobalamin conjugate (biotinyl-Cbl) were iodinated to follow their transport through the cell monolayer. Their apparent permeability coefficient (Papp) and transepithelial pathway were determined and compared to those for control radiolabeled markers [3H]-mannitol, [125I]-beta-lactoglobulin and [57Co]-cobalamin/intrinsic factor (Cbl/IF). The Papp of [125I]-avidin estimated at 2.8 x 10(-7) +/- 0.08 cm/s was close to that for mannitol that uses paracellular pathway. The binding of biotin or biotin conjugate to avidin enhanced its tetrameric conformation. The Papp for [125I]-avidin/biotin and [125I]- avidin/biotinyl-Cbl were respectively increased by 2-fold, compared to that for [125I]-avidin and 4-fold, compared to that for [125I]-beta-lactoglobulin and [54Co]-Cbl/IF. The protein was not accumulated in the cell and was found in intact form in the basolateral side, after its transport across the monolayer. Chloroquine (0.66 micromol/ml) did not significantly decrease the Papp for [125I]-avidin/biotinyl-Cbl. Conversely it decreased by 80% the Papp for Cbl/IF, that uses transepithelial pathway. Avidin (either saturated or not with biotin and biotinyl-Cbl) was able to cross the monolayer of Caco-2 cell line through a paracellular pathway. This study pointed out the interest for using this protein as a shuttle for increasing the transport rate of biotinylated compounds through fetal epithelial barriers. Copyright 2001 S. Karger AG, Basel

Reconstruction of Cysteine Biosynthesis Using Engineered Cysteine-Free and Methionine-Free Enzymes

Science.gov (United States)

Wang, Kendrick; Fujishima, Kosuke; Abe, Nozomi; Nakahigashi, Kenji; Endy, Drew; Rothschild, Lynn J.

2016-01-01

Ten of the proteinogenic amino acids can be generated abiotically while the remaining thirteen require biology for their synthesis. Paradoxically, the biosynthesis pathways observed in nature require enzymes that are made with the amino acids they produce. For example, Escherichia coli produces cysteine from serine via two enzymes that contain cysteine. Here, we substituted alternate amino acids for cysteine and also methionine, which is biosynthesized from cysteine, in serine acetyl transferase (CysE) and O-acetylserine sulfhydrylase (CysM). CysE function was rescued by cysteine-and-methionine-free enzymes and CysM function was rescued by cysteine-free enzymes. Structural modeling suggests that methionine stabilizes CysM and is present in the active site of CysM. Cysteine is not conserved among CysE and CysM protein orthologs, suggesting that cysteine is not functionally important for its own synthesis. Engineering biosynthetic enzymes that lack the amino acids being synthesized provides insights into the evolution of amino acid biosynthesis and pathways for bioengineering.

Effect of methionine supplementation in chicken feed on the quality and shelf life of fresh poultry meat.

Science.gov (United States)

Albrecht, Antonia; Herbert, Ulrike; Miskel, Dennis; Heinemann, Celine; Braun, Carina; Dohlen, Sophia; Zeitz, Johanna O; Eder, Klaus; Saremi, Behnam; Kreyenschmidt, Judith

2017-08-01

The aim of this study was to investigate the influence of different methionine sources and concentrations on the quality and spoilage process of broiler meat. The trial was comprised of 7 treatment groups: one basal group (suboptimal in Methionine+Cysteine; i.e., 0.89, 0.74, 0.69% in DM SID Met+Cys in starter, grower, and finisher diets, respectively) and 3 doses (0.10, 0.25, and 0.40%) of either DL-Methionine (DLM) or DL-2-hydroxy-4-methylthio butanoic acid (DL-HMTBA) on an equimolar basis of the DLM-supplemented groups. The broilers were fed the diets for 35 d, then slaughtered and processed. The filets were aerobically packed and stored under temperature controlled conditions at 4°C. Meat quality investigations were comprised of microbial investigations (total viable count and Pseudomonas spp.), pH and drip loss measurements of the filets. The shelf life of the meat samples was determined based on sensory parameters. After slaughtering, all supplemented meat samples showed a high quality, whereby no differences between the 2 methionine sources could be detected for the microbial load, pH, and drip loss. In comparison to the control group, the supplemented samples showed a higher sensory quality, characterized by a fresh smell and fresh red color. Methionine supplementation had a significant influence on meat quality parameters during storage. The microbial load, pH and drip loss of the chicken filets were positively correlated to the methionine concentration. Additionally, the microbial load at the end of storage was positively correlated to pH and drip loss values. Nevertheless, the microbial parameters were in a normal range and the positive correlation to methionine concentration did not affect the sensory shelf life. The mean sensory shelf life of the broiler filets varied between 7 to 9 d. During storage, no difference in the development of sensory parameters was observed between the supplemented groups, while the spoilage process of the basal group

Topoisomerase 1 Inhibition Promotes Cyclic GMP-AMP Synthase-Dependent Antiviral Responses.

Science.gov (United States)

Pépin, Geneviève; Nejad, Charlotte; Ferrand, Jonathan; Thomas, Belinda J; Stunden, H James; Sanij, Elaine; Foo, Chwan-Hong; Stewart, Cameron R; Cain, Jason E; Bardin, Philip G; Williams, Bryan R G; Gantier, Michael P

2017-10-03

Inflammatory responses, while essential for pathogen clearance, can also be deleterious to the host. Chemical inhibition of topoisomerase 1 (Top1) by low-dose camptothecin (CPT) can suppress transcriptional induction of antiviral and inflammatory genes and protect animals from excessive and damaging inflammatory responses. We describe the unexpected finding that minor DNA damage from topoisomerase 1 inhibition with low-dose CPT can trigger a strong antiviral immune response through cyclic GMP-AMP synthase (cGAS) detection of cytoplasmic DNA. This argues against CPT having only anti-inflammatory activity. Furthermore, expression of the simian virus 40 (SV40) large T antigen was paramount to the proinflammatory antiviral activity of CPT, as it potentiated cytoplasmic DNA leakage and subsequent cGAS recruitment in human and mouse cell lines. This work suggests that the capacity of Top1 inhibitors to blunt inflammatory responses can be counteracted by viral oncogenes and that this should be taken into account for their therapeutic development. IMPORTANCE Recent studies suggest that low-dose DNA-damaging compounds traditionally used in cancer therapy can have opposite effects on antiviral responses, either suppressing (with the example of CPT) or potentiating (with the example of doxorubicin) them. Our work demonstrates that the minor DNA damage promoted by low-dose CPT can also trigger strong antiviral responses, dependent on the presence of viral oncogenes. Taken together, these results call for caution in the therapeutic use of low-dose chemotherapy agents to modulate antiviral responses in humans. Copyright © 2017 Pépin et al.

21 CFR 172.372 - N-Acetyl-L-methionine.

Science.gov (United States)

2010-04-01

... and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.372 N-Acetyl-L-methionine. The food additive N-acetyl-L...

Diorganotin(IV) Complexes with Methionine Methyl Ester. Equilibria ...

African Journals Online (AJOL)

IV) (DBT) and diphenyltin(IV) (DPT) was investigated at 25 °C and 0.1 mol dm–3 ionic strength in water for dimethyltin(IV) and in 50 % dioxane–water mixture for dibutyltin(IV) and diphenyltin(IV). Methionine methyl ester forms1:1 and 1:2 ...

Role of Helicobacter pylori methionine sulfoxide reductase in urease maturation

Science.gov (United States)

Kuhns, Lisa G.; Mahawar, Manish; Sharp, Joshua S.; Benoit, Stéphane; Maier, Robert J.

2014-01-01

The persistence of the gastric pathogen Helicobacter pylori is due in part to urease and Msr (methionine sulfoxide reductase). Upon exposure to relatively mild (21% partial pressure of O2) oxidative stress, a Δmsr mutant showed both decreased urease specific activity in cell-free extracts and decreased nickel associated with the partially purified urease fraction as compared with the parent strain, yet urease apoprotein levels were the same for the Δmsr and wild-type extracts. Urease activity of the Δmsr mutant was not significantly different from the wild-type upon non-stress microaerobic incubation of strains. Urease maturation occurs through nickel mobilization via a suite of known accessory proteins, one being the GTPase UreG. Treatment of UreG with H2O2 resulted in oxidation of MS-identified methionine residues and loss of up to 70% of its GTPase activity. Incubation of pure H2O2-treated UreG with Msr led to reductive repair of nine methionine residues and recovery of up to full enzyme activity. Binding of Msr to both oxidized and non-oxidized UreG was observed by cross-linking. Therefore we conclude Msr aids the survival of H. pylori in part by ensuring continual UreG-mediated urease maturation under stress conditions. PMID:23181726

Retrospective evaluation of methionine intoxication associated with urinary acidifying products in dogs: 1,525 cases (2001-2012).

Science.gov (United States)

Hickey, Mara C; Son, Tolina T; Wismer, Tina

2015-01-01

To describe the signalment, clinical findings, timing of signs, outcome, and prognosis in a population of dogs exposed to methionine through the ingestion of urine acidifying products. Retrospective observational study from January 1, 2001 to December 31, 2012. Animal Poison Control Center. A total of 1,197 case calls yielding 1,525 dogs identified with presumed methionine ingestion. None. Records of dogs with presumptive methionine ingestion were reviewed from the American Society for the Prevention of Cruelty to Animals Animal Poison Control Center database. Ingested methionine doses ranged from 3.9 mg/kg to 23,462 mg/kg. Clinical signs developed in 47% of dogs. The most common clinical signs were gastrointestinal (GI) and neurologic. The mean onset of GI signs was 2.8 hours following ingestion. The mean onset of neurologic signs was 6.8 hours following ingestion. GI signs were identified with ingested doses ≥22.5 mg/kg. Vomiting was the most common GI sign. Neurologic signs were identified with ingested doses ≥94.6 mg/kg. Ataxia was the most common neurologic sign. Resolution of clinical signs occurred within 48 hours of ingestion, and no fatalities were reported. Prognosis for dogs with methionine intoxication is excellent. Vomiting and ataxia were the most common clinical signs associated with methionine toxicosis. © Veterinary Emergency and Critical Care Society 2015.

Dopamine D2 receptor function is compromised in the brain of the methionine sulfoxide reductase A knockout mouse

OpenAIRE

Oien, Derek B.; Ortiz, Andrea N.; Rittel, Alexander G.; Dobrowsky, Rick T.; Johnson, Michael A.; Levant, Beth; Fowler, Stephen C.; Moskovitz, Jackob

2010-01-01

Previous research suggests that brain oxidative stress and altered rodent locomotor behavior are linked. We observed bio-behavioral changes in methionine sulfoxide reductase A knockout mice associated with abnormal dopamine signaling. Compromised ability of these knockout mice to reduce methionine sulfoxide enhances accumulation of sulfoxides in proteins. We examined the dopamine D2-receptor function and expression, which has an atypical arrangement and quantity of methionine residues. Indeed...

Acceleration of selenium volatilization in seleniferous agricultural drainage sediments amended with methionine and casein

Energy Technology Data Exchange (ETDEWEB)

Banuelos, G.S. [USDA-ARS, Water Management Research Laboratory, Parlier, CA 93648 (United States)], E-mail: gbanuelos@fresno.ars.usda.gov; Lin, Z.-Q. [Department of Biological Sciences and Environmental Sciences Program, Southern Illinois University Edwardsville, Edwardsville, IL 62026-1651 (United States)

2007-12-15

Phytoremediation is potentially effective for managing excessive selenium (Se) in drainage sediment residing in the San Luis Drain in central California. This 2-year field study examined the feasibility of amending drainage sediment (containing 4.78 {mu}g Se g{sup -1}) with methionine and casein to enhance volatilization without or with vegetation of Sporobolus airoides. Results show that without organic amendments, rates of Se volatilization were less than 25 {mu}g m{sup -2} d{sup -1} in all plots. After amending the sediment with 71.4 mg methionine kg{sup -1} soil, Se volatilization rates were 434 {+-} 107 {mu}g m{sup -2} d{sup -1} in vegetated plots and 289 {+-} 117 {mu}g m{sup -2} d{sup -1} in irrigated bare plots. With the amendment of 572 mg casein kg{sup -1} soil, rates increased to 346 {+-} 103 {mu}g m{sup -2} d{sup -1} in irrigated bare plots and to 114 {+-} 55 {mu}g m{sup -2} d{sup -1} in vegetated plots. Both methionine and casein promoted biological remediation of Se via volatilization most effectively during the warmest months. - Amending drainage sediment with either methionine or casein promotes the volatilization of selenium.

Acceleration of selenium volatilization in seleniferous agricultural drainage sediments amended with methionine and casein

International Nuclear Information System (INIS)

Banuelos, G.S.; Lin, Z.-Q.

2007-01-01

Phytoremediation is potentially effective for managing excessive selenium (Se) in drainage sediment residing in the San Luis Drain in central California. This 2-year field study examined the feasibility of amending drainage sediment (containing 4.78 μg Se g -1 ) with methionine and casein to enhance volatilization without or with vegetation of Sporobolus airoides. Results show that without organic amendments, rates of Se volatilization were less than 25 μg m -2 d -1 in all plots. After amending the sediment with 71.4 mg methionine kg -1 soil, Se volatilization rates were 434 ± 107 μg m -2 d -1 in vegetated plots and 289 ± 117 μg m -2 d -1 in irrigated bare plots. With the amendment of 572 mg casein kg -1 soil, rates increased to 346 ± 103 μg m -2 d -1 in irrigated bare plots and to 114 ± 55 μg m -2 d -1 in vegetated plots. Both methionine and casein promoted biological remediation of Se via volatilization most effectively during the warmest months. - Amending drainage sediment with either methionine or casein promotes the volatilization of selenium

Myasthenia gravis: 75Se-seleno-methionine scanning of thymus gland

International Nuclear Information System (INIS)

Szobor, A.; Fornet, B.

1986-01-01

The 75 Se-seleno-methionine isotope thymus scanning was examined in a series of patients with myasthenia gravis. The patients were given 4 μC/kg hence a total of 250-300 μC 75 Se-seleno-methionine, intravenously. The method proved useful and informative in the diagnostics of myasthenia. Prior to thymectomy, the thymic tumour or a large gland could be observed and some hints could be gained for the biological activity of the gland. After the operation, the success of thymectomy could be checked and later a possible recidive could be shown or excluded. In non-operative cases the change in thymic activity could be followed which was an important sign of a malignant or tumorous growth of the thymus. (author)

Mechanism of oxidation of L-methionine by iron(III)

Indian Academy of Sciences (India)

phenanthroline complex have been studied in perchloric acid medium. The reaction is first order each in iron(III) and methionine. Increase in [phenanthroline] increases the rate while increase in [HClO4] decreases it. While the reactive species of the ...

Corynebacterium diphtheriae methionine sulfoxide reductase a exploits a unique mycothiol redox relay mechanism.

Science.gov (United States)

Tossounian, Maria-Armineh; Pedre, Brandán; Wahni, Khadija; Erdogan, Huriye; Vertommen, Didier; Van Molle, Inge; Messens, Joris

2015-05-01

Methionine sulfoxide reductases are conserved enzymes that reduce oxidized methionines in proteins and play a pivotal role in cellular redox signaling. We have unraveled the redox relay mechanisms of methionine sulfoxide reductase A of the pathogen Corynebacterium diphtheriae (Cd-MsrA) and shown that this enzyme is coupled to two independent redox relay pathways. Steady-state kinetics combined with mass spectrometry of Cd-MsrA mutants give a view of the essential cysteine residues for catalysis. Cd-MsrA combines a nucleophilic cysteine sulfenylation reaction with an intramolecular disulfide bond cascade linked to the thioredoxin pathway. Within this cascade, the oxidative equivalents are transferred to the surface of the protein while releasing the reduced substrate. Alternatively, MsrA catalyzes methionine sulfoxide reduction linked to the mycothiol/mycoredoxin-1 pathway. After the nucleophilic cysteine sulfenylation reaction, MsrA forms a mixed disulfide with mycothiol, which is transferred via a thiol disulfide relay mechanism to a second cysteine for reduction by mycoredoxin-1. With x-ray crystallography, we visualize two essential intermediates of the thioredoxin relay mechanism and a cacodylate molecule mimicking the substrate interactions in the active site. The interplay of both redox pathways in redox signaling regulation forms the basis for further research into the oxidative stress response of this pathogen. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Immune function and hematology of male cotton rats (Sigmodon hispidus) in response to food supplementation and methionine

Science.gov (United States)

Webb, R.E.; Leslie, David M.; Lochmiller, R.L.; Masters, R.E.

2003-01-01

We examined effects of supplementation of food quantity and quality (=enhanced methionine) on hematologic and immunologic parameters of wild, but enclosed, adult male cotton rats (Sigmodon hispidus) in north-central Oklahoma. Sheet metal enclosures were stocked with a high density of wild-caught cotton rats (160 animals/ha) and randomly assigned a treatment of no supplementation, mixed-ration supplementation or methionine-enhanced supplementation. Aside from small increases in counts of red blood cells and hematocrit levels, most indices of erythrocytic characteristics were not affected by supplementation with the mixed-ration or enhanced methionine. In contrast, platelet counts were highest in mixed-ration and methionine treatments and counts of total white blood cells were highest with methionine supplementation, albeit relative proportions of different leukocytes did not differ among treatments. Immunologically, neither delayed-type hypersensitivity response nor hemolytic-complement activity differed among treatments. Supplementation of food quantity and quality did not broadly affect hematologic parameters and immune function of male cotton rats, but enhanced platelet and leukocyte counts may confer advantages to overall health. Clarification of the role of such effects on population limitation or regulation requires additional research.

Hepatic metabolism of 11C-methionine and secretion of 11C-protein measured by PET in pigs

DEFF Research Database (Denmark)

Horsager, Jacob; Lausten, Susanne Bach; Bender, Dirk

2017-01-01

Hepatic amino acid metabolism and protein secretion are essential liver functions that may be altered during metabolic stress, e.g. after surgery. We wished to develop a dynamic liver PET method using the radiolabeled amino acid 11C-methionine to examine this question. Eleven 40-kg pigs were...... allocated to either laparotomy or pneumoperitoneum. 24 hours after surgery a 70-min dynamic PET scanning of the liver with arterial blood sampling was performed immediately after intravenous injection of 11C-methionine. Time course of arterial plasma 11C-methionine concentration was used as input function...

Purification and characterization of CDP-diacylglycerol synthase from Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Kelley, M.J.; Carman, G.M.

1987-01-01

The membrane-associated phospholipid biosynthetic enzyme CDP-diacylglycerol synthase (CTP:phosphatidate cytidylyltransferase was purified 2300-fold from Saccharomyces cerevisiae. The purification procedure included Triton X-100 solubilization of mitochondrial membranes, CDP-diacylglycerol-Sepharose affinity chromatography, and hydroxylapatite chromatography. The procedure resulted in a nearly homogeneous enzyme preparation as determined by native and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Radiation inactivation of mitochondrial associated and purified CDP-diacylglycerol synthase suggested that the molecular weight of the native enzyme was 114,000. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified enzyme preparation yielded two subunits with molecular weights of 56,000 and 54,000. Antibodies prepared against the purified enzyme immunoprecipitated CDP-diacylglycerol synthase activity and subunits. CDP-diacylglycerol synthase activity was dependent on magnesium ions and Triton X-100 at pH 6.5. Thio-reactive agents inhibited activity. The activation energy for the reaction was 9 kcal/mol, and the enzyme was thermally labile above 30 degrees C. The Km values for CTP and phosphatidate were 1 and 0.5 mM, respectively, and the Vmax was 4700 nmol/min/mg. Results of kinetic and isotopic exchange reactions suggested that the enzyme catalyzes a sequential Bi Bi reaction mechanism

Nitric Oxide Synthases Reveal a Role for Calmodulin in Controlling Electron Transfer

Science.gov (United States)

Abu-Soud, Husam M.; Stuehr, Dennis J.

1993-11-01

Nitric oxide (NO) is synthesized within the immune, vascular, and nervous systems, where it acts as a wide-ranging mediator of mammalian physiology. The NO synthases (EC 1.14.13.39) isolated from neurons or endothelium are calmodulin dependent. Calmodulin binds reversibly to neuronal NO synthase in response to elevated Ca2+, triggering its NO production by an unknown mechanism. Here we show that calmodulin binding allows NADPH-derived electrons to pass onto the heme group of neuronal NO synthase. Calmodulin-triggered electron transfer to heme was independent of substrate binding, caused rapid enzymatic oxidation of NADPH in the presence of O_2, and was required for NO synthesis. An NO synthase isolated from cytokine-induced macrophages that contains tightly bound calmodulin catalyzed spontaneous electron transfer to its heme, consistent with bound calmodulin also enabling electron transfer within this isoform. Together, these results provide a basis for how calmodulin may regulate NO synthesis. The ability of calmodulin to trigger electron transfer within an enzyme is unexpected and represents an additional function for calcium-binding proteins in biology.

Advanced glycation end products overload might explain intracellular cobalamin deficiency in renal dysfunction, diabetes and aging.

Science.gov (United States)

Obeid, Rima; Shannan, Batool; Herrmann, Wolfgang

2011-11-01

Advanced glycation end products (AGEs) contribute to aging. Cobalamin (Cbl) is required for cell growth and functions, and its deficiency causes serious complications. Diabetics and renal patients show high concentrations of Cbl, but metabolic evidence of Cbl deficiency that is reversible after Cbl treatment. Cbl might be sequestered in blood and cannot be delivered to the cell. Megalin mediates the uptake of transcobalamin-Cbl complex into the proximal tubule cells. Megalin is involved in the uptake and degradation of AGEs. In aging, diabetes or renal dysfunction, AGEs might overload megalin thus lowering Cbl uptake. Transcobalamin-Cbl might retain in blood. Shedding of megalin and transcobalamin receptor under glycation conditions is also a possible mechanism of this phenomenon. Copyright © 2011 Elsevier Ltd. All rights reserved.

Novel polyhydroxyalkanoate copolymers produced in Pseudomonas putida by metagenomic polyhydroxyalkanoate synthases.

Science.gov (United States)

Cheng, Jiujun; Charles, Trevor C

2016-09-01

Bacterially produced biodegradable polyhydroxyalkanoates (PHAs) with versatile properties can be achieved using different PHA synthases (PhaCs). This work aims to expand the diversity of known PhaCs via functional metagenomics and demonstrates the use of these novel enzymes in PHA production. Complementation of a PHA synthesis-deficient Pseudomonas putida strain with a soil metagenomic cosmid library retrieved 27 clones expressing either class I, class II, or unclassified PHA synthases, and many did not have close sequence matches to known PhaCs. The composition of PHA produced by these clones was dependent on both the supplied growth substrates and the nature of the PHA synthase, with various combinations of short-chain-length (SCL) and medium-chain-length (MCL) PHA. These data demonstrate the ability to isolate diverse genes for PHA synthesis by functional metagenomics and their use for the production of a variety of PHA polymer and copolymer mixtures.

Inhibition by methotrexate (MTX) polyglutamates (PGS) of folate-dependent biosyntheses in L1210 Leukemia cells

International Nuclear Information System (INIS)

Matherly, L.H.; Barlowe, C.K.; Goldman, I.D.

1986-01-01

The inhibition of folate-dependent pathways by MTX PGS was evaluated in folate-depleted L1210 cells incubated with (6S)5-formyl(CHO)tetrahydrofolate(FH 4 )(5μM). The accumulation of MTX PGS during exposure to MTX (10μM;3h) inhibited cell growth (>70%) under these conditions. In the presence of 5-CHO-FH 4 , carbon transfer from 14 C-formate or 3- 14 C-serine into purines, dTMP, and amino acids was suppressed following MTX-pretreatment, suggesting the formation of only low levels of FH 4 to drive these reactions. In cells treated with MTX (6S)5-CHO-[ 3 H]-FH 4 was metabolized predominantly to 10-CHO-[ 3 H]-FH 4 . While intracellular dihydrofolate (FH 2 ) increased 10-fold, indicating a block at FH 2 reductase by MTX PGS, FH 2 represented only 20% of the total metabolites of 5-CHO-FH 4 . The incorporation of 14 C from 5-[ 14 C]-CHO-FH 4 into serine and methionine was not affected by the presence of intracellular MTX PGS, however, carbon transfer into dTMP and purine nucleotides was reduced (50-60%). These findings demonstrate that MTX pretreatment inhibits de novo nucleotide and amino acid biosynthetic pathways even when high levels of reduced folates are present. The data suggest a suppression of dTMP synthase and the purine transformylase(s) by MTX and/or FH 2 PGS that accumulate in drug-treated cells. Inhibition of the purine biosynthetic steps appears to trap 10-CHO-FH 4 , limiting FH 4 for the synthesis of dTMP, serine, and methionine

Mechanistic and Kinetic Study of Singlet O2 Oxidation of Methionine by On-Line Electrospray Ionization Mass Spectrometry.

Science.gov (United States)

Liu, Fangwei; Lu, Wenchao; Yin, Xunlong; Liu, Jianbo

2016-01-01

We report a reaction apparatus developed to monitor singlet oxygen ((1)O2) reactions in solution using on-line ESI mass spectrometry and spectroscopy measurements. (1)O2 was generated in the gas phase by the reaction of H2O2 with Cl2, detected by its emission at 1270 nm, and bubbled into aqueous solution continuously. (1)O2 concentrations in solution were linearly related to the emission intensities of airborne (1)O2, and their absolute scales were established based on a calibration using 9,10-anthracene dipropionate dianion as an (1)O2 trapping agent. Products from (1)O2 oxidation were monitored by UV-Vis absorption and positive/negative ESI mass spectra, and product structures were elucidated using collision-induced dissociation-tandem mass spectrometry. To suppress electrical discharge in negative ESI of aqueous solution, methanol was added to electrospray via in-spray solution mixing using theta-glass ESI emitters. Capitalizing on this apparatus, the reaction of (1)O2 with methionine was investigated. We have identified methionine oxidation intermediates and products at different pH, and measured reaction rate constants. (1)O2 oxidation of methionine is mediated by persulfoxide in both acidic and basic solutions. Persulfoxide continues to react with another methionine, yielding methionine sulfoxide as end-product albeit with a much lower reaction rate in basic solution. Density functional theory was used to explore reaction potential energy surfaces and establish kinetic models, with solvation effects simulated using the polarized continuum model. Combined with our previous study of gas-phase methionine ions with (1)O2, evolution of methionine oxidation pathways at different ionization states and in different media is described.

Platelet-derived growth factor (PDGF) stimulates glycogen synthase activity in 3T3 cells

International Nuclear Information System (INIS)

Chan, C.P.; Bowen-Pope, D.F.; Ross, R.; Krebs, E.G.

1986-01-01

Hormonal regulation of glycogen synthase, an enzyme that can be phosphorylated on multiple sites, is often associated with changes in its phosphorylation state. Enzyme activation is conventionally monitored by determining the synthase activity ratio [(activity in the absence of glucose 6-P)/(activity in the presence of glucose 6-P)]. Insulin causes an activation of glycogen synthase with a concomitant decrease in its phosphate content. In a previous report, the authors showed that epidermal growth factor (EGF) increases the glycogen synthase activity ratio in Swiss 3T3 cells. The time and dose-dependency of this response was similar to that of insulin. Their recent results indicate that PDGF also stimulates glycogen synthase activity. Enzyme activation was maximal after 30 min. of incubation with PDGF; the time course observed was very similar to that with insulin and EGF. At 1 ng/ml (0.03nM), PDGF caused a maximal stimulation of 4-fold in synthase activity ratio. Half-maximal stimulation was observed at 0.2 ng/ml (6 pM). The time course of changes in enzyme activity ratio closely followed that of 125 I-PDGF binding. The authors data suggest that PDGF, as well as EFG and insulin, may be important in regulating glycogen synthesis through phosphorylation/dephosphorylation mechanisms

S-adenosyl-L-methionine for alcoholic liver diseases

DEFF Research Database (Denmark)

Rambaldi, A; Gluud, C

2001-01-01

Alcohol is a major cause of liver disease in the Western world today. S-adenosyl-L-methionine (SAMe) acts as a methyl donor for all known biological methylation reactions and participates in the synthesis of glutathione, the main cellular anti-oxidant. Randomised clinical trials have addressed...... the question whether SAMe has any efficacy in patients with alcoholic liver diseases....

Ceramide synthase 2 facilitates S1P-dependent egress of thymocytes into the circulation in mice.

Science.gov (United States)

Rieck, Michael; Kremser, Christiane; Jobin, Katarzyna; Mettke, Elisabeth; Kurts, Christian; Gräler, Markus; Willecke, Klaus; Kolanus, Waldemar

2017-04-01

Well-defined gradients of the lipid mediator sphingosine-1-phosphate (S1P) direct chemotactic egress of mature thymocytes from the thymus into the circulation. Although it is known that these gradients result from low S1P levels in the thymic parenchyma and high S1P concentrations at the exit sites and in the plasma, the biochemical mechanisms that regulate these differential S1P levels remain unclear. Several studies demonstrated that ceramide synthase 2 (Cers2) regulates the levels of the S1P precursor sphingosine. We, therefore, investigated whether Cers2 is involved in the regulation of S1P gradients and S1P-dependent egress into the circulation. By analyzing Cers2-deficient mice, we demonstrate that Cers2 limits the levels of S1P in thymus and blood to maintain functional S1P gradients that mediate thymocyte emigration into the circulation. This function is specific for Cers2, as we also show that Cers4 is not involved in the regulation of thymic egress. Our study identified Cers2 as an important regulator of S1P-dependent thymic egress, and thus contributes to the understanding of how S1P gradients are maintained in vivo. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A copper-methionine interaction controls the pH-dependent activation of peptidylglycine monooxygenase.

Science.gov (United States)

Bauman, Andrew T; Broers, Brenda A; Kline, Chelsey D; Blackburn, Ninian J

2011-12-20

The pH dependence of native peptidylglycine monooxygenase (PHM) and its M314H variant has been studied in detail. For wild-type (WT) PHM, the intensity of the Cu-S interaction visible in the Cu(I) extended X-ray absorption fine structure (EXAFS) data is inversely proportional to catalytic activity over the pH range of 3-8. A previous model based on more limited data was interpreted in terms of two protein conformations involving an inactive Met-on form and an active flexible Met-off form [Bauman, A. T., et al. (2006) Biochemistry 45, 11140-11150] that derived its catalytic activity from the ability to couple into vibrational modes critical for proton tunneling. The new studies comparing the WT and M314H variant have led to the evolution of this model, in which the Met-on form has been found to be derived from coordination of an additional Met residue, rather than a more rigid conformer of M314 as previously proposed. The catalytic activity of the mutant decreased by 96% because of effects on both k(cat) and K(M), but it displayed the same activity-pH profile with a maximum around pH 6. At pH 8, the reduced Cu(I) form gave spectra that could be simulated by replacement of the Cu(M) Cu-S(Met) interaction with a Cu-N/O interaction, but the data did not unambiguously assign the ligand to the imidazole side chain of H314. At pH 3.5, the EXAFS still showed the presence of a strong Cu-S interaction, establishing that the Met-on form observed at low pH in WT cannot be due to a strengthening of the Cu(M)-methionine interaction but must arise from a different Cu-S interaction. Therefore, lowering the pH causes a conformational change at one of the Cu centers that brings a new S donor residue into a favorable orientation for coordination to copper and generates an inactive form. Cys coordination is unlikely because all Cys residues in PHM are engaged in disulfide cross-links. Sequence comparison with the PHM homologues tyramine β-monooxygenase and dopamine �

The cellulose synthase companion proteins act non-redundantly with CELLULOSE SYNTHASE INTERACTING1/POM2 and CELLULOSE SYNTHASE 6

OpenAIRE

Endler, Anne; Schneider, Rene; Kesten, Christopher; Lampugnani, Edwin R.; Persson, Staffan

2016-01-01

Cellulose is a cell wall constituent that is essential for plant growth and development, and an important raw material for a range of industrial applications. Cellulose is synthesized at the plasma membrane by massive cellulose synthase (CesA) complexes that track along cortical microtubules in elongating cells of Arabidopsis through the activity of the protein CELLULOSE SYNTHASE INTERACTING1 (CSI1). In a recent study we identified another family of proteins that also are associated with the ...

Incorporation of DL-methionine /sup 3/H into the rat brain in the course of triethyl tin sulphate intoxication

Energy Technology Data Exchange (ETDEWEB)

Kozik, M B; Ozarzewska, E; Piechowski, A [Akademia Medyczna, Poznan (Poland)

1976-01-01

The incorporation of DL-methionine /sup 3/H into the rat brain in the course of acute edema caused by the triethyl tin sulphate (TET) was investigated by autoradiography. The results indicate that TET intoxication effects in lower incorporation of methionine into the experimental rat brain in comparison to that in normal animals. The changes in dynamics of DL-methionine /sup 3/H incorporation after TET intoxication are presented. The possible pathogenetic mechanism of the observed changes is discussed.

Solid state radiolysis of sulphur-containing amino acids. Cysteine, cystine and methionine

International Nuclear Information System (INIS)

Franco Cataldo; Pietro Ragni; Susana Iglesias-Groth; Arturo Manchado

2011-01-01

The sulphur-containing proteinaceous amino acids l-cysteine, l-cystine and l-methionine were irradiated in the solid state to a dose of 3.2 MGy. This dose corresponds to that delivered by radionuclide decay in a timescale of 1.05 x 10 9 years to the organic matter buried at a depth >20 m in comets and asteroids. The purity of the sulphur-containing amino acids was studied by differential scanning calorimetry (DSC) before and after the solid state radiolysis and the preservation of the chirality after the radiolysis was studied by chirooptical methods (optical rotatory dispersion, ORD) and by FT-IR spectroscopy. Although the high radiation dose of 3.2 MGy delivered, all the amino acids studied show a high radiation resistance. The best radiation resistance was offered by l-cysteine. The radiolysis of l-cysteine leads to the formation of l-cystine. The radiation resistance of l-methionine is not at the level of l-cysteine but also l-methionine is able to survive the dose of 3.2 MGy. Furthermore in all cases examined the preservation of chirality after radiolysis was clearly observed by the ORD spectroscopy although a certain level of radioracemization was measured in all cases. The radioracemization is minimal in the case of l-cysteine and is more pronounced in the case of l-methionine. In conclusion, the study shows that the sulphur-containing amino acids can survive for 1.05 x 10 9 years and, after extrapolation of the data, even to the age of the Solar System i.e. to 4.6 x 10 9 years. (author)

Multi-substrate terpene synthases: their occurrence and physiological significance

Directory of Open Access Journals (Sweden)

Leila Pazouki

2016-07-01

Full Text Available Terpene synthases are responsible for synthesis of a large number of terpenes in plants using substrates provided by two distinct metabolic pathways, the mevalonate-dependent pathway that is located in cytosol and has been suggested to be responsible for synthesis of sesquiterpenes (C15, and 2-C-methyl-D-erythritol-4-phosphate pathway located in plastids and suggested to be responsible for the synthesis of hemi- (C5, mono- (C10 and diterpenes (C20. Recent advances in characterization of genes and enzymes responsible for substrate and end product biosynthesis as well as efforts in metabolic engineering have demonstrated existence of a number of multi-substrate terpene synthases. This review summarizes the progress in the characterization of such multi-substrate terpene synthases and suggests that the presence of multi-substrate use might have been significantly underestimated. Multi-substrate use could lead to important changes in terpene product profiles upon substrate profile changes under perturbation of metabolism in stressed plants as well as under certain developmental stages. We therefore argue that multi-substrate use can be significant under physiological conditions and can result in complicate modifications in terpene profiles.

Effect of Low Protein-Methionine-and-Lysine-Supplemented Diets ...

African Journals Online (AJOL)

Two experiments were conducted to investigate the effect of supplementing low CP diets with methionine and lysine on broiler performance, carcass measure and their immune response against Infectious Bursa Disease (IBD) virus. In Experiment 1, ten diets were formulated. Diet 1 (control diet) contained 23.0% CP and ...

Factors influencing gene silencing of granule-bound starch synthase in potato

NARCIS (Netherlands)

Heilersig, H.J.B.

2005-01-01

In the past, antisense RNA technology was used to modify the composition of potato tuber starch. Potato starch comprises amylose and amylopectin, polymers of glucose. Amylose production in potato is completely dependent on the presence of granule-bound starch synthase I (GBSSI). Inhibition of GBSSI

Stabilization of sulfide cations: mechanisms relevant to oxidation of peptides and proteins containing methionine

International Nuclear Information System (INIS)

Bobrowski, K.; Hug, G.L.; Pogocki, D.; Horner, G.; Marciniak, B.; Schoneich, C.

2006-01-01

compounds for the study of peptide free radical chemistry. While appearing very small to be models for proteins, they have unique feature of having no terminal groups. This makes them invaluable for studying interactions between side chains and peptide bonds. A small model cyclic dipeptide c-(L-methionyl-L-methionine) was oxidized by . OH radicals generated via pulse radiolysis, and the ensuing reactive intermediates were monitored by time-resolved UV/Vis spectroscopic and conductometric techniques. The picture that emerged from this investigation showed there was an efficient formation of the Met(S N) radicals, in spite of the close proximity of sulfur atoms, located in the side chain of methionine residues, and in spite of the close proximity of sulfur atoms and oxygen atoms, located in the peptide bonds. Moreover, it was observed, for the first time, that formation of Met(S N) radicals involved the hydrogen atom of the peptide bond. In this concerted process, elimination of OH in the form of water involves a simultaneous N-deprotonation from the amide nitrogen, followed by formation of Met(S N) radicals in the form of a thermodynamically favorable five-membered ring. These Met(S N) radicals converted further into intramolecular three-electron bonded Met(S S) + and Met(S O) + radical cations via a pH-dependent mechanism. A preference for Met(S+ ) stabilization in the form of intramolecular three-electron bonded Met(S N) radicals over intermolecular three-electron bonded Met(S S)+ dimeric radical cations was observed in c-(L-Met-D-Met). Lack of intramolecular three-electron bonded Met(S S)+ radical cations illustrates that a close contact between two sulfur atoms is sterically restricted in the D-L enantiomer. Moreover, contrary to c-(L-Met-L-Met), most of Met(S+ ) radicals derived from c-(L-Met-D-Met) undergo efficient deprotonation in the α-position to the sulfur, yielding carbon-centered α-(alkylthio)alkyl radicals. To support the mechanism, quantum mechanical (DFT

10597 influence of hypo and hyper methionine supplementation

African Journals Online (AJOL)

dell

It is therefore important to ensure that poultry diets contain enough methionine to ensure the desired growth, feed conversion and immune response, but not too much so as to be toxic to the birds. Newcastle disease is one of the most rampant viral diseases of poultry with a prevalence rate of 28.9% in Nigeria [10]. Two of the ...

Oxidation of methionine - is it limiting the diagnostic properties of 99mTc-labeled Exendin-4, a Glucagon-Like Peptide-1 receptor agonist?

Science.gov (United States)

Janota, Barbara; Karczmarczyk, Urszula; Laszuk, Ewa; Garnuszek, Piotr; Mikołajczak, Renata

2016-01-01

Preliminary clinical evaluation of 99mTc-EDDA/HYNIC-Met14-Exendin-4 showed that the complex offers new diagnostic possibilities for insulinoma and MTC. Exendin-4 contains methionine at position 14 in the amino acid chain, which may be oxidized to methionine sulfoxide and, from the pharmaceutical point of view, the oxidized moiety becomes an undesired impurity in the final radioactive preparation. Therefore, the aim of this study was to investigate the influence of commonly used methods to eliminate the effect of methionine oxidation in peptides, i.e. the replacement of methionine by norleucine (Nle) and the addition of L-methionine, on the in vitro stability and the biodistribution. 99mTc-EDDA/HYNIC-Met14-Exendin-4, 99mTc-EDDA/HYNIC-Nle14-Exendin-4, 99mTc-EDDA/HYNIC-Met14-Ex-endin-4 with the addition of L-methionine and an oxidized form of Exendin-4, i.e. 99mTc-EDDA/HYNIC-Met14(ox)-Exendin-4 were compared in vivo with 68Ga-NODAGA-Nle14-Exendin-4 in normal Wistar rats. The stability and lipophilicity were determined in vitro. Biodistribution studies confirmed the specific uptake of all tested complexes in the GLP-1 positive organs: lungs, pancreas and stomach. The uptake of 99mTc-EDDA/HYNIC-Met14-Exendin-4 with the addition of L-methionine and for 68Ga-NODAGA-Nle14-Exendin-4 at 1h p.i. was around 2-fold higher than that of 99mTc-EDDA/HYNIC-Met14-Exendin-4 and 99mTc-EDDA/HYNIC-Nle14-Exendin-4. Although the substitution of methionine by norleucine in the HYNIC-Exendin-4 did not result in improved bio-distribution, the use of L-methionine, as the excipient that inhibits the oxidation of methionine in the peptide chain resulted in higher lung/blood and stomach/blood uptake ratios. Our results confirmed that methionine at position 14 of amino acid chain of Exendin-4 plays an important role in the interaction with GLP-1 receptor positive tissue.

[Features of allele polymorphism of genes involved in homocysteine and folate metabolism in patients with atherosclerosis of the lower extremity arteries].

Science.gov (United States)

Klenkova, N A; Kapustin, S I; Saltykova, N B; Shmeleva, V M; Blinov, M N

2009-01-01

Under study were features of allele polymorphism of genes of methylenetetrahydrofolate reductase (MTHFR C677T and A1298C), methionine synthase (MS A 2756G), methionine synthase reductase (MTRR A66G) and methylenetetrahydrofolate dehydrogenase (MTHFD G1958A) in patients with atherosclerosis of the lower extremity arteries (ALEA). Patients with hyperhomocysteinemia (HHcy) had statistically significant increase of allele MTHFR 677T and MTRR 66GG as compared both with the control group and with the group of patients without HHcy. It suggests that polymorphism of genes involved in homocystein and folate metabolism might affect the risk of HHcy in patients with ALEA.

Cranial neuronavigation with direct integration of 11C methionine positron emission tomography (PET) data - results of a pilot study in 32 surgical cases

International Nuclear Information System (INIS)

Braun, V.; Dempf, S.; Richter, H.P.; Weller, R.; Reske, S.-N.; Schanchenmayr, W.

2002-01-01

MRI detects small intracranial lesions, but has difficulties in differentiating between tumor, gliosis and edema. 11 C methionine-PET may help to overcome this problem. For its appropriate intra-operative use, it must be integrated into neuronavigation. We present the results of our pilot study with this method. 32 patients with 34 intracranial lesions detected by MRI underwent additional 11 C methionine-PET, because the pathophysiological behavior or the tumor delineation was unclear. All lesions were treated surgically. In 25 patients PET data could be integrated directly into cranial neuronavigation. 11 C methionine uptake was observed in 27/34 lesions, 26 of them were tumors: 14 malignant and 7 benign gliomas, 3 gliomas without further histological typing, one Ewing sarcoma and one non-Hodgkin lymphoma. Only one 11 C methionine positive lesion was non-tumorous: it was staged as post-irradiation necrosis in a patient operated on for a malignant glioma. 3/7 11 C-methionine negative lesions were classified as gliosis (n = 2) and M. Whipple (n = 1), but 4/7 were tumors: 2 astrocytomas WHO o II, 1 DNT and one astrocytoma WHO o III. The sensitivity of 11 C methionine-PET was 87 %, the specificity 75 %, the positive predictive value 96 % and the negative predictive value 43 %. In all tumorous cases with positive tracer uptake the borderline area of the tumor was better defined by C methionine-PET than by MRI. Interpretation: A positive 11 C methionine-PET is highly suspicious of a tumor, a negative one does not exclude it. 11 C methionine-PET seems to be more sensitive than MRI for differentiating between tumor and edema or gliosis. Simultaneous integration MRI and 11 C methionine-PET into cranial neuronavigation can facilitate cross total tumor removal in glioma surgery. (author)

Effect of herbal choline and rumen-protected methionine on lamb ...

African Journals Online (AJOL)

Elizabeth A Mendoza B MD

2018-01-30

Jan 30, 2018 ... oral doses of rumen-protected methionine (RPM) (0 and 1.5 g/day) and ... and stimulating glucose and cholesterol synthesis. .... The in vitro gas production indicates that half of herbal choline is fermented at 18 hours (Table 2),.

The browning value changes and spectral analysis on the Maillard reaction product from glucose and methionine model system

Science.gov (United States)

Al-Baarri, A. N.; Legowo, A. M.; Widayat

2018-01-01

D-glucose has been understood to provide the various effect on the reactivity in Maillard reaction resulting in the changes in physical performance of food product. Therefore this research was done to analyse physical appearance of Maillard reaction product made of D-glucose and methionine as a model system. The changes in browning value and spectral analysis model system were determined. The glucose-methionine model system was produced through the heating treatment at 50°C and RH 70% for 24 hours. The data were collected for every three hour using spectrophotometer. As result, browning value was elevated with the increase of heating time and remarkably high if compare to the D-glucose only. Furthermore, the spectral analysis showed that methionine turned the pattern of peak appearance. As conclusion, methionine raised the browning value and changed the pattern of spectral analysis in Maillard reaction model system.

Evaluation of Four Commercial Sources of Synthetic Methionine on ...

African Journals Online (AJOL)

Four diets were formulated to meet standard requirements at both starter and finisher phases in which the four commercial brands of synthetic methionine; CHL Rhodimet Analogue and DSM were supplemented in diets to represent treatments 1, 2, 3 and 4, respectively. Eight weeks period of the experiment. Data was ...

Methionine in Velvet Bean ( Mucuna pruriens ) Based Broiler Starter ...

African Journals Online (AJOL)

The performance of broiler chicks fed starter diets containing 30% raw or heat treated, and 20% heat treated velvet beans with varying levels of methionine was determined. The influence of varying levels of heat treated velvet beans on growth and carcass characteristics of finishing broilers was also investigated. There was ...

Transient hypoxia stimulates mitochondrial biogenesis in brain subcortex by a neuronal nitric oxide synthase-dependent mechanism

Science.gov (United States)

The adaptive mechanisms that protect brain metabolism during and after hypoxia, for instance, during hypoxic preconditioning, are coordinated in part by nitric oxide (NO). We tested the hypothesis that acute transient hypoxia stimulates NO synthase (NOS)-activated mechanisms of m...

Radioactive methionine: determination, and distribution of radioactivity in the sulfur, methyl and 4-carbon moieties

International Nuclear Information System (INIS)

Giovanelli, J.; Mudd, S.H.

1985-01-01

A simple and inexpensive method is described for isolation and determination of [ 14 C]methionine in the non-protein fraction of tissues extensively labeled with 14 C. The effectiveness of the method was demonstrated by isolation of non-protein [ 14 C]methionine (as the carboxymethylsulfonium salt) of proven radiopurity from the plant Lemna which had been grown for a number of generations on (U- 14 C]sucrose and contained a 2000-fold excess of 14 C in undefined non-protein compounds. An advantage is that the isolated methioninecarboxymethlysulfonium salt is readily degraded to permit separate determination of radioactivity in the 4-carbon, methyl and sulfur moieties of methionine. During this work, a facile labilization of 3 H attached to the (carboxy)methylene carbon of methioninecarboxymethylsulfonium salt was observed. This labilization is ascribed to formation of a sulfur ylid. (Auth.)

Converting S-limonene synthase to pinene or phellandrene synthases reveals the plasticity of the active site.

Science.gov (United States)

Xu, Jinkun; Ai, Ying; Wang, Jianhui; Xu, Jingwei; Zhang, Yongkang; Yang, Dong

2017-05-01

S-limonene synthase is a model monoterpene synthase that cyclizes geranyl pyrophosphate (GPP) to form S-limonene. It is a relatively specific enzyme as the majority of its products are composed of limonene. In this study, we converted it to pinene or phellandrene synthases after introducing N345A/L423A/S454A or N345I mutations. Further studies on N345 suggest the polarity of this residue plays a critical role in limonene production by stabilizing the terpinyl cation intermediate. If it is mutated to a non-polar residue, further cyclization or hydride shifts occurs so the carbocation migrates towards the pyrophosphate, leading to the production of pinene or phellandrene. On the other hand, mutant enzymes that still possess a polar residue at this position produce limonene as the major product. N345 is not the only polar residue that may stabilize the terpinyl cation because it is not strictly conserved among limonene synthases across species and there are also several other polar residues in this area. These residues could form a "polar pocket" that may collectively play this stabilizing role. Our study provides important insights into the catalytic mechanism of limonene synthases. Furthermore, it also has wider implications on the evolution of terpene synthases. Copyright © 2017 Elsevier Ltd. All rights reserved.

Kinetics of selenium 75 - methionine and its metabolites in various organs and the fetoplacentar unity of rats during normal and disturbed gestation

International Nuclear Information System (INIS)

Bender, G.

1980-01-01

Studies were carried out on the following 3 groups of rats: animals with normal gestation, disturbed gestation and non-gestating control animals. Relative organ activity of the mothers and of the fetoplacental unit was measured as a function of time following injection with the selenium-75 labelled amino acid, methionine. During gestation amino acid methabolism in the mothers was accelerated, this effect being less apparent in mothers with disturbed gestation; in the latter case an increased renal loss of plasma proteins and amino acids can be assumed. High activity in the methylation cycle is characteristic for the foetus. Foetal growth retardation as a consequence of reduced placental blood supply leads to a redistribution of methionine-utilisation, whereby transmethylation is favoured over protein incorporation. In addition to these systemic-dependent changes, the reduced placental diffusion leads to a local decrease in diaplacental transport. (orig./MG) [de

Conversion of nicotinic acid to trigonelline is catalyzed by N-methyltransferase belonged to motif B′ methyltransferase family in Coffea arabica

International Nuclear Information System (INIS)

Mizuno, Kouichi; Matsuzaki, Masahiro; Kanazawa, Shiho; Tokiwano, Tetsuo; Yoshizawa, Yuko; Kato, Misako

2014-01-01

Graphical abstract: Trigonelline synthase catalyzes the conversion of nicotinic acid to trigonelline. We isolated and characterized trigonelline synthase gene(s) from Coffea arabica. - Highlights: • Trigonelline is a major compound in coffee been same as caffeine is. • We isolated and characterized trigonelline synthase gene. • Coffee trigonelline synthases are highly homologous with coffee caffeine synthases. • This study contributes the fully understanding of pyridine alkaloid metabolism. - Abstract: Trigonelline (N-methylnicotinate), a member of the pyridine alkaloids, accumulates in coffee beans along with caffeine. The biosynthetic pathway of trigonelline is not fully elucidated. While it is quite likely that the production of trigonelline from nicotinate is catalyzed by N-methyltransferase, as is caffeine synthase (CS), the enzyme(s) and gene(s) involved in N-methylation have not yet been characterized. It should be noted that, similar to caffeine, trigonelline accumulation is initiated during the development of coffee fruits. Interestingly, the expression profiles for two genes homologous to caffeine synthases were similar to the accumulation profile of trigonelline. We presumed that these two CS-homologous genes encoded trigonelline synthases. These genes were then expressed in Escherichiacoli, and the resulting recombinant enzymes that were obtained were characterized. Consequently, using the N-methyltransferase assay with S-adenosyl[methyl- 14 C]methionine, it was confirmed that these recombinant enzymes catalyzed the conversion of nicotinate to trigonelline, coffee trigonelline synthases (termed CTgS1 and CTgS2) were highly identical (over 95% identity) to each other. The sequence homology between the CTgSs and coffee CCS1 was 82%. The pH-dependent activity curve of CTgS1 and CTgS2 revealed optimum activity at pH 7.5. Nicotinate was the specific methyl acceptor for CTgSs, and no activity was detected with any other nicotinate derivatives, or with

Conversion of nicotinic acid to trigonelline is catalyzed by N-methyltransferase belonged to motif B′ methyltransferase family in Coffea arabica

Energy Technology Data Exchange (ETDEWEB)

Mizuno, Kouichi, E-mail: koumno@akita-pu.ac.jp [Faculty of Bioresource Sciences, Akita Prefectural University, Akita City, Akita 010-0195 (Japan); Matsuzaki, Masahiro [Faculty of Bioresource Sciences, Akita Prefectural University, Akita City, Akita 010-0195 (Japan); Kanazawa, Shiho [Graduate School of Humanities and Sciences, Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo 112-8610 (Japan); Tokiwano, Tetsuo; Yoshizawa, Yuko [Faculty of Bioresource Sciences, Akita Prefectural University, Akita City, Akita 010-0195 (Japan); Kato, Misako [Graduate School of Humanities and Sciences, Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo 112-8610 (Japan)

2014-10-03

Graphical abstract: Trigonelline synthase catalyzes the conversion of nicotinic acid to trigonelline. We isolated and characterized trigonelline synthase gene(s) from Coffea arabica. - Highlights: • Trigonelline is a major compound in coffee been same as caffeine is. • We isolated and characterized trigonelline synthase gene. • Coffee trigonelline synthases are highly homologous with coffee caffeine synthases. • This study contributes the fully understanding of pyridine alkaloid metabolism. - Abstract: Trigonelline (N-methylnicotinate), a member of the pyridine alkaloids, accumulates in coffee beans along with caffeine. The biosynthetic pathway of trigonelline is not fully elucidated. While it is quite likely that the production of trigonelline from nicotinate is catalyzed by N-methyltransferase, as is caffeine synthase (CS), the enzyme(s) and gene(s) involved in N-methylation have not yet been characterized. It should be noted that, similar to caffeine, trigonelline accumulation is initiated during the development of coffee fruits. Interestingly, the expression profiles for two genes homologous to caffeine synthases were similar to the accumulation profile of trigonelline. We presumed that these two CS-homologous genes encoded trigonelline synthases. These genes were then expressed in Escherichiacoli, and the resulting recombinant enzymes that were obtained were characterized. Consequently, using the N-methyltransferase assay with S-adenosyl[methyl-{sup 14}C]methionine, it was confirmed that these recombinant enzymes catalyzed the conversion of nicotinate to trigonelline, coffee trigonelline synthases (termed CTgS1 and CTgS2) were highly identical (over 95% identity) to each other. The sequence homology between the CTgSs and coffee CCS1 was 82%. The pH-dependent activity curve of CTgS1 and CTgS2 revealed optimum activity at pH 7.5. Nicotinate was the specific methyl acceptor for CTgSs, and no activity was detected with any other nicotinate derivatives, or

Vitamin B(12) dependent changes in mouse spinal cord expression of vitamin B(12) related proteins and the epidermal growth factor system

DEFF Research Database (Denmark)

Mutti, Elena; Lildballe, Dorte L; Kristensen, Lise

2013-01-01

Chronic vitamin B(12) (cobalamin) deficiency in the mammalian central nervous system causes degenerative damage, especially in the spinal cord. Previous studies have shown that cobalamin status alters spinal cord expression of epidermal growth factor (EGF) and its receptor in rats. Employing...

Amino acid nutrition beyond methionine and lysine for milk protein

Science.gov (United States)

Amino acids are involved in many important physiological processes affecting the production, health, and reproduction of high-producing dairy cows. Most research and recommendations for lactating dairy cows has focused on methionine and lysine for increasing milk protein yield. This is because these...

Effect of supplementation with methionine and different fat sources on the glutathione redox system of growing chickens.

Science.gov (United States)

Németh, Katalin; Mézes, M; Gaál, T; Bartos, A; Balogh, K; Husvéth, F

2004-01-01

The effect of supplementary methionine and fats of different saturation levels on the glutathione redox system of growing broiler cockerels was studied. The diet of three groups of chicks was supplemented with corn germ oil, beef tallow and fish oil at the levels of 30 g/kg and 50 g/kg of feed, respectively. The diet of further three groups was supplemented with methionine (5 g/kg of feed) in addition to the different fat sources. Control chicks were fed with a compound feed without methionine and fat supplementation. Reduced glutathione (GSH) and glutathione disulphide (GSSG) content as well as glutathione peroxidase activity in the liver were determined and GSH/GSSG ratio was calculated at day old and then at one and three weeks of age. Our results indicate that supplementary methionine stimulates both the synthesis of the glutathione redox system and glutathione peroxidase activity in growing chickens in the first period of postnatal life, when the risk of lipid peroxidation is high due to feeding unsaturated fats in the diet.

Protection against UVB-induced oxidative stress in human skin cells and skin models by methionine sulfoxide reductase A.

Science.gov (United States)

Pelle, Edward; Maes, Daniel; Huang, Xi; Frenkel, Krystyna; Pernodet, Nadine; Yarosh, Daniel B; Zhang, Qi

2012-01-01

Environmental trauma to human skin can lead to oxidative damage of proteins and affect their activity and structure. When methionine becomes oxidized to its sulfoxide form, methionine sulfoxide reductase A (MSRA) reduces it back to methionine. We report here the increase in MSRA in normal human epidermal keratinocytes (NHEK) after ultraviolet B (UVB) radiation, as well as the reduction in hydrogen peroxide levels in NHEK pre-treated with MSRA after exposure. Further, when NHEK were pre-treated with a non-cytotoxic pentapeptide containing methionine sulfoxide (metSO), MSRA expression increased by 18.2%. Additionally, when the media of skin models were supplemented with the metSO pentapeptide and then exposed to UVB, a 31.1% reduction in sunburn cells was evident. We conclude that the presence of MSRA or an externally applied peptide reduces oxidative damage in NHEK and skin models and that MSRA contributes to the protection of proteins against UVB-induced damage in skin.

Preclinical evaluation of an {sup 18}F-trifluoroborate methionine derivative for glioma imaging

Energy Technology Data Exchange (ETDEWEB)

Yang, Xiangyu [Medical School of Southeast University, Jiangsu Key Laboratory of Molecular Imaging and Functional Imaging, Department of Radiology, Zhongda Hospital, Nanjing (China); National Institutes of Health (NIH), Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, Bethesda, MD (United States); Liu, Zhibo; Zhang, Huimin; Li, Zhu; Niu, Gang; Chen, Xiaoyuan [National Institutes of Health (NIH), Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, Bethesda, MD (United States); Munasinghe, Jeeva P. [NIH, Mouse Imaging Facility, National Institute of Neurological Disorders and Stroke, Bethesda, MD (United States); Teng, Gaojun [Medical School of Southeast University, Jiangsu Key Laboratory of Molecular Imaging and Functional Imaging, Department of Radiology, Zhongda Hospital, Nanjing (China)

2018-04-15

{sup 11}C-methionine (MET) is one of the most commonly used amino acid tracers for PET imaging of brain tumors. In this study, we report an {sup 18}F-labeled boron-derived methionine analogue, denoted as {sup 18}F-B-MET, as a potential substitute of {sup 11}C-MET for glioma PET imaging. {sup 19}F-B-MET was synthesized from readily available chemicals according to our previous publication. For kit development, {sup 19}F-B-MET was aliquoted in quantities of 10 nmol for on-demand one-step labeling. The {sup 18}F-labeling was performed by {sup 18}F-{sup 19}F isotope exchange, and quality control was performed by both HPLC and radio-TLC. Uptake of the tracer was determined in GL26, C6 and U87 tumor cells. PET imaging and the biodistribution assay were performed on mice bearing subcutaneous or orthotopic C6 and U87 tumor xenografts. Starting with 740-1110 MBq {sup 18}F-fluoride, >370 MBq of {sup 18}F-B-MET was obtained in 25 min (n = 5) with >99% purity and high specific activity (>37 GBq/μmol). {sup 18}F-B-MET demonstrated excellent in vitro stability with <1% decomposition after incubation with plasma for 2 h. In vitro cell uptake assay showed that {sup 18}F-B-MET accumulated in tumor cells in a time dependent manner and could be competitively inhibited by natural methionine and other L-type transporter transported amino acids. In vivo biodistribution and imaging studies showed high tumor accumulation (2.99 ± 0.23 %ID/g, n = 6) compared with low uptake of brain (0.262 ± 0.05 %ID/g, n = 6) at 60 min after injection in a subcutaneous C6 tumor model. Orthotropic C6 and U87 tumors were clearly visualized with high tumor to brain ratios at 60 min post-injection, corroborating with tumor L-type amino acid transporter 1 (LAT-1) expression levels. {sup 18}F-B-MET was radiolabeled with high yield in a one-step labeling process, showed excellent pharmacokinetic properties in vivo, with high tumor-to-brain contrast. (orig.)

Measurement of methionine level with the LC-ESI-MS/MS method in schizophrenic patients.

Science.gov (United States)

Kulaksizoglu, S; Kulaksizoglu, B; Ellidag, H Y; Eren, E; Yilmaz, N; Baykal, A

2016-01-01

The purpose of this study was to evaluate plasma methionine levels by using liquid chromatography electrospray ionization-tandem mass spectroscopy (LC-ESI-MS/MS) in schizophrenic patients. A twelve-point standard graph was drawn, and the recovery rate, the intra-day and inter-day coefficients of variation (CV), the limit of detection (LOD), and the limit of quantification (LOQ) were evaluated. The y and R2 values of the standard graph equation were determined as 0.011x + 0.0179 and 0.9989, respectively, and the graph remained linear until the 200 µmol/l level. The intra-day coefficients of variation of the samples (n = 10) containing 8, 28, and 58 µmol/l methionine were determined as 2.68, 3.10, and 3.79%, respectively; while their inter-day coefficients of variation were determined as 2.98, 3.19, and 3.84%. The LOD and LOQ values were determined as 0.04 and 0.1 µmol/l, respectively, while the mean recovery rates were determined as 101.7 and 99.3%. Plasma methionine values were measured as 21.5 (19.5-24,6) µmol/l for the patient group, 17.8 (16.3-20.1) µmol/l for the control group, and the difference between the two groups was statistically significant (p = 0.03). LC-ESI-MS/MS method represents a fairly sensitive, economic, and rapid analysis that requires very little sample and is suitable for measuring methionine levels in schizophrenic patients.

On the Correlation between EPR and Positron Annihilation Measurements on gamma-Irradiated Acetyl Methionine

DEFF Research Database (Denmark)

Eldrup, Morten Mostgaard; Lund-Thomsen, E.; Mogensen, O. E.

1972-01-01

The dose dependence of the relative EPR signal intensity and positron lifetime spectrum was measured for γ‐irradiated acetyl methionine in the dose range from 0 to 30 Mrad. Angular correlation measurements were performed for the doses 0 and 30 Mrad. The result of the irradiation was the creation...... of EPR centers and inhibition of positronium formation. For one sample, irradiated with a dose of 30 Mrad, EPR and positron lifetime spectra were followed over a period of 50 days after the irradiation. The inhibiting effect and the EPR signal intensity decreased with time. No simple correlation could...... be established between the number of EPR centers and the positron annihilation data, but other possible explanations are discussed....

Influence of UV-A or UV-B light and of the nitrogen source on the induction of ferredoxin-dependent glutamate synthase in etiolated tomato cotyledons

International Nuclear Information System (INIS)

Migge, A.; Carrayol, E.; Hirel, B.; Lohmann, M.; Meya, G.; Becker, T.W.

1998-01-01

The influence of ultraviolet A (UV-A) or B (UV-B) light and of the nitrogen source on the induction of ferredoxin-dependent glutamate synthase (Fd-GOGAT, EC 1.4.7.1) was examined in etiolated cotyledons of tomato (Lycopersicon escu- lentum L.). The Fd-GOGAT activity increased upon illumination of etiolated tomato cotyledons with UV-A or UV-B light. This stimulation of Fd-GOGAT activity was correlated with an increase in both the Fd-GOGAT transcript level and the Fd-GOGAT protein abundance. These results suggest that UV-A or UV-B light stimulates the de novo synthesis of Fd-GOGAT in etiolated tomato cotyledons. Both UV-A and UV-B light failed to influence the activity of NADH-GOGAT (EC 1.4.1.14) in etiolated tomato cotyledons. Taken together, our data indicate that the tomato genes encoding Fd- or NADH-dependent glutamate synthase are regulated differently by UV-A or UV-B light. No difference with respect to both the Fd-GOGAT transcript and protein abundance was found between cotyledons of tomato seedlings grown with either nitrate or ammonium as the sole N-source in the dark or in white light. In addition, the increase in the Fd-GOGAT protein pool induced by white light in etiolated nitrate-grown tomato seedling cotyledons was similar to that induced by white light in etiolated ammonium-grown tomato seedling cotyledons. These results show that the tomato Fd-GOGAT protein level does not depend strongly on the nature of the nitrogen source and that there appears to be no major stimulatory effect on the Fd-GOGAT protein pool produced by nitrate during the illumination of etiolated tomato cotyledons

Variability of plasma and urine betaine in diabetes mellitus and its relationship to methionine load test responses: an observational study

Directory of Open Access Journals (Sweden)

Lever Michael

2012-07-01

Full Text Available Abstract Background Since betaine is an osmolyte and methyl donor, and abnormal betaine loss is common in diabetes mellitus (>20% patients, we investigated the relationship between betaine and the post-methionine load rise in homocysteine, in diabetes and control subjects. The post-methionine load test is reported to be both an independent vascular risk factor and a measure of betaine sufficiency. Methods Patients with type 2 diabetes (n = 34 and control subjects (n = 17 were recruited. We measured baseline fasting plasma and 4-hour post-methionine load (L-methionine, 0.1 mg/kg body weight concentrations of homocysteine, betaine, and the betaine metabolite N,N-dimethylglycine. Baseline urine excretions of betaine, dimethylglycine and glucose were measured on morning urine samples as the ratio to urine creatinine. Statistical determinants of the post-methionine load increase in homocysteine were identified in multiple linear regression models. Results Plasma betaine concentrations and urinary betaine excretions were significantly (p p = 0.00014 and plasma dimethylglycine concentrations (p = 0.039 were also more variable. In diabetes, plasma betaine was a significant negative determinant (p  Conclusions Both high and low plasma betaine concentrations, and high and low urinary betaine excretions, are more prevalent in diabetes. The availability of betaine affects the response in the methionine load test. The benefits of increasing betaine intake should be investigated.

Study of Methionine, Vitamin B12, and Folic Acid Status in Coronary Atherosclerotic Male Patients

OpenAIRE

M Djalali; SR A Hoseiny; F Siassi; N Fardad; R Ghiasvand; TR Neyestani

2007-01-01

Background: Increased level of serum homocysteine is one of the risk factor of atherosclerosis. Its production related in some sulfur amino acids such as methionine. Some important cofactors that are involved in metabolic pathways of this amino acid are folate and vitamin B12. We have assessed the status of methionine, folic acid, and vitamin B12 in some coronary atherosclerotic male patients.Methods: In this case-control study, 46 cases of coronary atherosclerosis were selected from male pat...

Diagnostic and Prognostic Significance of Methionine Uptake and Methionine Positron Emission Tomography Imaging in Gliomas

Directory of Open Access Journals (Sweden)

Kamalakannan Palanichamy

2017-11-01

Full Text Available The present most common image diagnostic tracer in clinical practice for glioma is 18F-fluorodeoxyglucose (FDG positron emission tomography (PET for brain tumors diagnosis and prognosis. PET is a promising molecular imaging technique, which provides real-time information on the metabolic behavior of the tracer. The diffusive nature of glioblastoma (GBM and heterogeneity often make the radiographic detection by FDG-PET inaccurate, and there is no gold standard. FDG-PET often leads to several controversies in making clinical decisions due to their uptake by normal surrounding tissues, and pose a challenge in delineating treatment-induced necrosis, edema, inflammation, and pseudoprogression. Thus, it is imperative to find new criteria independent of conventional morphological diagnosis to demarcate normal and tumor tissues. We have provided proof of concept studies for 11C methionine-PET (MET-PET imaging of gliomas, along with prognostic and diagnostic significance. MET-PET is not widely used in the United States, though clinical trials from Japan and Germany suggesting the diagnostic ability of MET-PET imaging are superior to FDG-PET imaging for brain tumors. A major impediment is the availability of the onsite cyclotron and isotopic carbon chemistry facilities. In this article, we have provided the scientific rationale and advantages of the use of MET-PET as GBM tracers. We extend our discussion on the expected pitfalls of using MET-PET and ways to overcome them by incorporating a translational component of profiling gene status in the methionine metabolic pathway. This translational correlative component to the MET-PET clinical trials can lead to a better understanding of the existing controversies and can enhance our knowledge for future randomization of GBM patients based on their tumor gene signatures to achieve better prognosis and treatment outcome.

Fluence dependence of the ultraviolet-light-induced accumulation of chalcone synthase mRNA and effects of blue and far-red light in cultured parsley

International Nuclear Information System (INIS)

Bruns, B.; Hahlbrock, K.; Schäfer, E.

1986-01-01

The fluence dependence of the time course of accumulation of chalcone synthase mRNA in ultraviolet (UV)-light-irradiated cell suspension cultures of parsley (Petroselinum crispum) and the additional effects of blue and far-red light have been investigated. Variations of the UV fluence had no detectable influence on the initial rate of increase in mRNA amount or translational activity, nor on the preceding lag period of approximately 3 h, but strongly influenced the duration of the transient increase. The effects were the same whether the fluence rate or the time of irradiation was varied to obtain a given fluence. Blue-light pretreatment of the cells resulted in increased amounts of mRNA and abolished the apparent lag period. This effect remained cryptic without the subsequent UV-light treatment. Irradiation with long-wavelength far-red light following UV-light pulses shortened the duration of the mRNA accumulation period. This effect was not altered by a preceding blue-light treatment. Thus, three photoreceptors, a UV-B receptor, a blue-light receptor and phytochrome, participate in the regulation of chalcone synthase mRNA accumulation in this system

Calcium/calmodulin-dependent kinase II and nitric oxide synthase 1-dependent modulation of ryanodine receptors during β-adrenergic stimulation is restricted to the dyadic cleft.

Science.gov (United States)

Dries, Eef; Santiago, Demetrio J; Johnson, Daniel M; Gilbert, Guillaume; Holemans, Patricia; Korte, Sanne M; Roderick, H Llewelyn; Sipido, Karin R

2016-10-15

The dyadic cleft, where coupled ryanodine receptors (RyRs) reside, is thought to serve as a microdomain for local signalling, as supported by distinct modulation of coupled RyRs dependent on Ca 2+ /calmodulin-dependent kinase II (CaMKII) activation during high-frequency stimulation. Sympathetic stimulation through β-adrenergic receptors activates an integrated signalling cascade, enhancing Ca 2+ cycling and is at least partially mediated through CaMKII. Here we report that CaMKII activation during β-adrenergic signalling is restricted to the dyadic cleft, where it enhances activity of coupled RyRs thereby contributing to the increase in diastolic events. Nitric oxide synthase 1 equally participates in the local modulation of coupled RyRs. In contrast, the increase in the Ca 2+ content of the sarcoplasmic reticulum and related increase in the amplitude of the Ca 2+ transient are primarily protein kinase A-dependent. The present data extend the concept of microdomain signalling in the dyadic cleft and give perspectives for selective modulation of RyR subpopulations and diastolic events. In cardiac myocytes, β-adrenergic stimulation enhances Ca 2+ cycling through an integrated signalling cascade modulating L-type Ca 2+ channels (LTCCs), phospholamban and ryanodine receptors (RyRs). Ca 2+ /calmodulin-dependent kinase II (CaMKII) and nitric oxide synthase 1 (NOS1) are proposed as prime mediators for increasing RyR open probability. We investigate whether this pathway is confined to the high Ca 2+ microdomain of the dyadic cleft and thus to coupled RyRs. Pig ventricular myocytes are studied under whole-cell voltage-clamp and confocal line-scan imaging with Fluo-4 as a [Ca 2+ ] i indicator. Following conditioning depolarizing pulses, spontaneous RyR activity is recorded as Ca 2+ sparks, which are assigned to coupled and non-coupled RyR clusters. Isoproterenol (ISO) (10 nm) increases Ca 2+ spark frequency in both populations of RyRs. However, CaMKII inhibition reduces

Molecular mechanism of methionine differentiation in high and low ...

African Journals Online (AJOL)

User

2011-05-09

May 9, 2011 ... Key words: Maize, methionine, zein, storage protein, amino acid, real time PCR. INTRODUCTION ... programs should be started with main objectives to increase and ... (Woo et al., 2001), while beta zein have interaction with delta zein ... sion analysis of 27 kDa gamma zein and 16 kDa gamma zein, 22 kDa ...

Structure of dimeric, recombinant Sulfolobus solfataricus phosphoribosyl diphosphate synthase

DEFF Research Database (Denmark)

Andersen, Rune W.; Lo Leggio, Leila; Hove-Jensen, Bjarne

2015-01-01

The enzyme 5-phosphoribosyl-1-α-diphosphate (PRPP) synthase (EC 2.7.6.1) catalyses the Mg2+-dependent transfer of a diphosphoryl group from ATP to the C1 hydroxyl group of ribose 5-phosphate resulting in the production of PRPP and AMP. A nucleotide sequence specifying Sulfolobus solfataricus PRPP...

S-Inosyl-L-Homocysteine Hydrolase, a Novel Enzyme Involved in S-Adenosyl-L-Methionine Recycling.

Science.gov (United States)

Miller, Danielle; Xu, Huimin; White, Robert H

2015-07-01

S-Adenosyl-L-homocysteine, the product of S-adenosyl-L-methionine (SAM) methyltransferases, is known to be a strong feedback inhibitor of these enzymes. A hydrolase specific for S-adenosyl-L-homocysteine produces L-homocysteine, which is remethylated to methionine and can be used to regenerate SAM. Here, we show that the annotated S-adenosyl-L-homocysteine hydrolase in Methanocaldococcus jannaschii is specific for the hydrolysis and synthesis of S-inosyl-L-homocysteine, not S-adenosyl-L-homocysteine. This is the first report of an enzyme specific for S-inosyl-L-homocysteine. As with S-adenosyl-L-homocysteine hydrolase, which shares greater than 45% sequence identity with the M. jannaschii homologue, the M. jannaschii enzyme was found to copurify with bound NAD(+) and has Km values of 0.64 ± 0.4 mM, 0.0054 ± 0.006 mM, and 0.22 ± 0.11 mM for inosine, L-homocysteine, and S-inosyl-L-homocysteine, respectively. No enzymatic activity was detected with S-adenosyl-L-homocysteine as the substrate in either the synthesis or hydrolysis direction. These results prompted us to redesignate the M. jannaschii enzyme an S-inosyl-L-homocysteine hydrolase (SIHH). Identification of SIHH demonstrates a modified pathway in this methanogen for the regeneration of SAM from S-adenosyl-L-homocysteine that uses the deamination of S-adenosyl-L-homocysteine to form S-inosyl-L-homocysteine. In strictly anaerobic methanogenic archaea, such as Methanocaldococcus jannaschii, canonical metabolic pathways are often not present, and instead, unique pathways that are deeply rooted on the phylogenetic tree are utilized by the organisms. Here, we discuss the recycling pathway for S-adenosyl-L-homocysteine, produced from S-adenosyl-L-methionine (SAM)-dependent methylation reactions, which uses a hydrolase specific for S-inosyl-L-homocysteine, an uncommon metabolite. Identification of the pathways and the enzymes involved in the unique pathways in the methanogens will provide insight into the

Free methionine supplementation limits alcohol-induced liver damage in rats

DEFF Research Database (Denmark)

Parlesak, Alexandr; Bode, C.; Bode, J.C.

1998-01-01

Alcohol feeding to rats that were submitted to a jejunoileal bypass operation has been shown to result in liver damage being comparable with alcohol-induced liver disease in man. In the present study, a striking effect of free methionine consumption on histological liver injury, triglyceride accu...

Trans and cis effects of axial fluoroalkyl ligands in vitamin B12 analogues: relationship between alkyl- and fluoroalkyl-cobalamins.

Science.gov (United States)

Randaccio, Lucio; Brancatelli, Giovanna; Demitri, Nicola; Dreos, Renata; Hickey, Neal; Siega, Patrizia; Geremia, Silvano

2013-12-02

CF2HCbl, CF3Cbl , and CF3CH2Cbl have been synthesized and characterized in solution by (1)H NMR and UV-vis spectroscopy, and their X-ray crystal structures have been determined using synchrotron radiation. The structure of CF3CH2Cbl is reported for the first time, whereas those of CF2HCbl and CF3Cbl are re-examined to obtain more precise structural data. Comparison of the structural data obtained with the alkylcobalamin analogues, MeCbl and EtCbl, indicates that the Co-C and Co-NB3 bond lengths are shorter in the fluoroalkylcobalamins. The structural data of the fluoroalkylcobalamins previously reported in the literature had been conflicting in this regard. Thus, a much less dramatic shortening of the two axial bonds was found for CF3Cbl, whereas in the case of CF2HCbl, the Co-NB3 bond length is shorter than in MeCbl. Direct comparison of the structures of CF3CH2Cbl and EtCbl indicates a large distortion of the axial fragment in the former case that can be attributed to steric effects. A number of previously reported correlations of the effect of the β-ligand on the structure and properties of cobalamins are re-examined in light of the present results. Particular emphasis is placed on the axial fragment. This analysis substantially confirms and, with the new data reported here, adjusts and expands the data set for correlations between trans and cis influences of the β-ligand of cobalamins and their structure (Co-X and Co-NB3 distances and corrin fold angle) and properties (UV-vis spectra, NMR spectra, and pK(base-off)).

The Methionine Transamination Pathway Controls Hepatic Glucose Metabolism through Regulation of the GCN5 Acetyltransferase and the PGC-1α Transcriptional Coactivator*

OpenAIRE

Tavares, Clint D. J.; Sharabi, Kfir; Dominy, John E.; Lee, Yoonjin; Isasa, Marta; Orozco, Jose M.; Jedrychowski, Mark P.; Kamenecka, Theodore M.; Griffin, Patrick R.; Gygi, Steven P.; Puigserver, Pere

2016-01-01

Methionine is an essential sulfur amino acid that is engaged in key cellular functions such as protein synthesis and is a precursor for critical metabolites involved in maintaining cellular homeostasis. In mammals, in response to nutrient conditions, the liver plays a significant role in regulating methionine concentrations by altering its flux through the transmethylation, transsulfuration, and transamination metabolic pathways. A comprehensive understanding of how hepatic methionine metabol...

Cell cycle phase dependent emergence of thymidylate synthase studied by monoclonal antibody (M-TS-4).

Science.gov (United States)

Shibui, S; Hoshino, T; Iwasaki, K; Nomura, K; Jastreboff, M M

1989-05-01

A method of identifying thymidylate synthase (TS) at the cellular level was developed using anti-TS monoclonal antibody (M-TS-4), a monoclonal antibody created against purified TS from a HeLa cell line. In HeLa cells and four human glioma cell lines (U-251, U-87, 343-MGA, and SF-188), TS was identified primarily in the cytoplasm. Autoradiographic and flow cytometric studies showed that TS appeared mainly in the G1 phase and subsided early in the S phase; thus, the G1 phase can be divided into TS-positive and -negative fractions. Nuclear TS was not demonstrated unequivocally with M-TS-4, and the relationship between nuclear TS and DNA synthesis could not be determined. Although the percentage of TS-positive cells was larger than the S-phase fraction measured by autoradiography after a pulse of tritiated thymidine or by the immunoperoxidase method using BUdR, the ratios were within a similar range (1.2-1.4) in all cell lines studied. Therefore, the S-phase fraction can be estimated indirectly from the percentage of TS-positive cells measured by M-TS-4. Because the emergence of TS detected by our method is cell cycle dependent, M-TS-4 may be useful for biochemical studies of TS and for cytokinetic analysis.

CTP synthase forms cytoophidia in the cytoplasm and nucleus

International Nuclear Information System (INIS)

Gou, Ke-Mian; Chang, Chia-Chun; Shen, Qing-Ji; Sung, Li-Ying; Liu, Ji-Long

2014-01-01

CTP synthase is an essential metabolic enzyme responsible for the de novo synthesis of CTP. Multiple studies have recently showed that CTP synthase protein molecules form filamentous structures termed cytoophidia or CTP synthase filaments in the cytoplasm of eukaryotic cells, as well as in bacteria. Here we report that CTP synthase can form cytoophidia not only in the cytoplasm, but also in the nucleus of eukaryotic cells. Both glutamine deprivation and glutamine analog treatment promote formation of cytoplasmic cytoophidia (C-cytoophidia) and nuclear cytoophidia (N-cytoophidia). N-cytoophidia are generally shorter and thinner than their cytoplasmic counterparts. In mammalian cells, both CTP synthase 1 and CTP synthase 2 can form cytoophidia. Using live imaging, we have observed that both C-cytoophidia and N-cytoophidia undergo multiple rounds of fusion upon glutamine analog treatment. Our study reveals the coexistence of cytoophidia in the cytoplasm and nucleus, therefore providing a good opportunity to investigate the intracellular compartmentation of CTP synthase. - Highlights: • CTP synthase forms cytoophidia not only in the cytoplasm but also in the nucleus. • Glutamine deprivation and Glutamine analogs promotes cytoophidium formation. • N-cytoophidia exhibit distinct morphology when compared to C-cytoophidia. • Both CTP synthase 1 and CTP synthase 2 form cytoophidia in mammalian cells. • Fusions of cytoophidia occur in the cytoplasm and nucleus

CTP synthase forms cytoophidia in the cytoplasm and nucleus

Energy Technology Data Exchange (ETDEWEB)

Gou, Ke-Mian [MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT (United Kingdom); State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193 (China); Chang, Chia-Chun [Institute of Biotechnology, National Taiwan University, Taipei, Taiwan, ROC (China); Shen, Qing-Ji [MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT (United Kingdom); Sung, Li-Ying, E-mail: liyingsung@ntu.edu.tw [Institute of Biotechnology, National Taiwan University, Taipei, Taiwan, ROC (China); Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan, ROC (China); Liu, Ji-Long, E-mail: jilong.liu@dpag.ox.ac.uk [MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT (United Kingdom)

2014-04-15

CTP synthase is an essential metabolic enzyme responsible for the de novo synthesis of CTP. Multiple studies have recently showed that CTP synthase protein molecules form filamentous structures termed cytoophidia or CTP synthase filaments in the cytoplasm of eukaryotic cells, as well as in bacteria. Here we report that CTP synthase can form cytoophidia not only in the cytoplasm, but also in the nucleus of eukaryotic cells. Both glutamine deprivation and glutamine analog treatment promote formation of cytoplasmic cytoophidia (C-cytoophidia) and nuclear cytoophidia (N-cytoophidia). N-cytoophidia are generally shorter and thinner than their cytoplasmic counterparts. In mammalian cells, both CTP synthase 1 and CTP synthase 2 can form cytoophidia. Using live imaging, we have observed that both C-cytoophidia and N-cytoophidia undergo multiple rounds of fusion upon glutamine analog treatment. Our study reveals the coexistence of cytoophidia in the cytoplasm and nucleus, therefore providing a good opportunity to investigate the intracellular compartmentation of CTP synthase. - Highlights: • CTP synthase forms cytoophidia not only in the cytoplasm but also in the nucleus. • Glutamine deprivation and Glutamine analogs promotes cytoophidium formation. • N-cytoophidia exhibit distinct morphology when compared to C-cytoophidia. • Both CTP synthase 1 and CTP synthase 2 form cytoophidia in mammalian cells. • Fusions of cytoophidia occur in the cytoplasm and nucleus.

Glycogen synthase activation by sugars in isolated hepatocytes.

Science.gov (United States)

Ciudad, C J; Carabaza, A; Bosch, F; Gòmez I Foix, A M; Guinovart, J J

1988-07-01

We have investigated the activation by sugars of glycogen synthase in relation to (i) phosphorylase a activity and (ii) changes in the intracellular concentration of glucose 6-phosphate and adenine nucleotides. All the sugars tested in this work present the common denominator of activating glycogen synthase. On the other hand, phosphorylase a activity is decreased by mannose and glucose, unchanged by galactose and xylitol, and increased by tagatose, glyceraldehyde, and fructose. Dihydroxyacetone exerts a biphasic effect on phosphorylase. These findings provide additional evidence proving that glycogen synthase can be activated regardless of the levels of phosphorylase a, clearly establishing that a nonsequential mechanism for the activation of glycogen synthase occurs in liver cells. The glycogen synthase activation state is related to the concentrations of glucose 6-phosphate and adenine nucleotides. In this respect, tagatose, glyceraldehyde, and fructose deplete ATP and increase AMP contents, whereas glucose, mannose, galactose, xylitol, and dihydroxyacetone do not alter the concentration of these nucleotides. In addition, all these sugars, except glyceraldehyde, increase the intracellular content of glucose 6-phosphate. The activation of glycogen synthase by sugars is reflected in decreases on both kinetic constants of the enzyme, M0.5 (for glucose 6-phosphate) and S0.5 (for UDP-glucose). We propose that hepatocyte glycogen synthase is activated by monosaccharides by a mechanism triggered by changes in glucose 6-phosphate and adenine nucleotide concentrations which have been described to modify glycogen synthase phosphatase activity. This mechanism represents a metabolite control of the sugar-induced activation of hepatocyte glycogen synthase.

Identification and molecular characterization of the nicotianamine synthase gene family in bread wheat.

Science.gov (United States)

Bonneau, Julien; Baumann, Ute; Beasley, Jesse; Li, Yuan; Johnson, Alexander A T

2016-12-01

Nicotianamine (NA) is a non-protein amino acid involved in fundamental aspects of metal uptake, transport and homeostasis in all plants and constitutes the biosynthetic precursor of mugineic acid family phytosiderophores (MAs) in graminaceous plant species. Nicotianamine synthase (NAS) genes, which encode enzymes that synthesize NA from S-adenosyl-L-methionine (SAM), are differentially regulated by iron (Fe) status in most plant species and plant genomes have been found to contain anywhere from 1 to 9 NAS genes. This study describes the identification of 21 NAS genes in the hexaploid bread wheat (Triticum aestivum L.) genome and their phylogenetic classification into two distinct clades. The TaNAS genes are highly expressed during germination, seedling growth and reproductive development. Fourteen of the clade I NAS genes were up-regulated in root tissues under conditions of Fe deficiency. Protein sequence analyses revealed the presence of endocytosis motifs in all of the wheat NAS proteins as well as chloroplast, mitochondrial and secretory transit peptide signals in four proteins. These results greatly expand our knowledge of NAS gene families in graminaceous plant species as well as the genetics underlying Fe nutrition in bread wheat. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Synthesis and study of catalytic application of l-methionine protected gold nanoparticles

Science.gov (United States)

Raza, Akif; Javed, Safdar; Qureshi, Muhammad Zahid; khan, Muhammad Usman; Khan, Muhammad Saleem

2017-10-01

Gold nanoparticle is growing class of nanotechnology due to large number of uses. We synthesized stable l-methionine protected gold nanoparticles (AuNps) by in situ reduction of HAuCl4 using sodium borohydrate as reducing and l-methionine as stabilizing agent in an aqueous medium. Different parameters (pH, capping agent, precursor salt, and heating time) were optimized to see the effect on the size of particles. Double beam spectrophotometer was used to carry out the spectroscopic studies. It was observed that pH and concentration of reducing salt are deciding factors in controlling the size and morphology of AuNps. Scanning electron microscopy (SEM) verified the formation of AuNPs as predicted by UV-Vis spectra. The interaction of AuNPs with l-methionine was confirmed by Fourier Transform Infrared (FTIR). The reduction of 4-nitrophenol acted as standard of reaction to check the response of AuNps catalyst. Complete reduction of 4-nitrophenol was accomplished by AuNps sol in just 60 s. Fastest reduction rate was observed with smaller spherical particles. This study concluded that size and shape of AuNps can be monitored by controlling the pH, concentration of capping and reducing agent. It also provides an economical solution to aquatic environment in terms of time saving and use of small volume of catalytic solution for reduction of several other toxic organic pollutants.

Effect of methionine and lactic acid bacteria as aflatoxin binder on broiler performance

Science.gov (United States)

Istiqomah, Lusty; Damayanti, Ema; Julendra, Hardi; Suryani, Ade Erma; Sakti, Awistaros Angger; Anggraeni, Ayu Septi

2017-06-01

The use of aflatoxin binder product based amino acids, lacic acid bacteria, and natural product gived the opportunity to be an alternative biological decontamination of aflatoxins. A study was conducted to determine the efficacy of aflatoxin binder administration (amino acid methionine and lactic acid bacteria (Lactobacillus plantarum G7)) as feed additive on broiler performance. In this study, 75 Lohmann unsexed day old chicks were distributed randomly into 5 units of cages, each filled with 15 broilers. Five cages were assigned into 5 treatments groups and fed with feed contained aflatoxin. The treatments as follow: P1 (aflatoxin feed without aflatoxin binder), P3 (aflatoxin feed + 0.8% of methionine + 1% of LAB), P4 (aflatoxin feed + 1.2% of methionine + 1% of LAB), P5 (aflatoxin feed + 1% of LAB), and K0 (commercial feed). The measurement of aflatoxin content in feed was performed by Enzyme Linked Immunosorbent Assay method using AgraQuant® Total Aflatoxin Assay Romer Labs procedure. The experimental period was 35 days with feeding and drinking ad libitum. LAB was administered into drinking water, while methionine into feed. Vaccination program of Newcastle Disease (ND) was using active vaccine at 4 and 18 day old, while Infectious Bursal Disease (IBD) was given at 8 day old. Parameter of body weight was observed weekly, while feed consumption noted daily. The result showed that aflatoxin in feed for 35 days period did not significantly affect the body weight gain and feed conversion. The lowest percentage of organ damage at 21 day old was found in P5 treatment (55%), while at 35day old was found in P4 treatment (64%). It could be concluded that technological process of detoxifying aflatoxin could be applied in an attempt to reduce the effect on the toxicity of aflatoxin in poultry feed.

Threonine phosphorylation of rat liver glycogen synthase

International Nuclear Information System (INIS)

Arino, J.; Arro, M.; Guinovart, J.J.

1985-01-01

32 P-labeled glycogen synthase specifically immunoprecipitated from 32 P-phosphate incubated rat hepatocytes contains, in addition to [ 32 P] phosphoserine, significant levels of [ 32 P] phosphothreonine. When the 32 P-immunoprecipitate was cleaved with CNBr, the [ 32 P] phosphothreonine was recovered in the large CNBr fragment (CB-2, Mapp 28 Kd). Homogeneous rat liver glycogen synthase was phosphorylated by all the protein kinases able to phosphorylate CB-2 in vitro. After analysis of the immunoprecipitated enzyme for phosphoaminoacids, it was observed that only casein kinase II was able to phosphorylate on threonine and 32 P-phosphate was only found in CB-2. These results demonstrate that rat liver glycogen synthase is phosphorylated at threonine site(s) contained in CB-2 and strongly indicate that casein kinase II may play a role in the ''in vivo'' phosphorylation of liver glycogen synthase. This is the first protein kinase reported to phosphorylate threonine residues in liver glycogen synthase

Choline and methionine differentially alter methyl carbon metabolism in bovine neonatal hepatocytes.

Science.gov (United States)

Chandler, Tawny L; White, Heather M

2017-01-01

Intersections in hepatic methyl group metabolism pathways highlights potential competition or compensation of methyl donors. The objective of this experiment was to examine the expression of genes related to methyl group transfer and lipid metabolism in response to increasing concentrations of choline chloride (CC) and DL-methionine (DLM) in primary neonatal hepatocytes that were or were not exposed to fatty acids (FA). Primary hepatocytes isolated from 4 neonatal Holstein calves were maintained as monolayer cultures for 24 h before treatment with CC (61, 128, 2028, and 4528 μmol/L) and DLM (16, 30, 100, 300 μmol/L), with or without a 1 mmol/L FA cocktail in a factorial arrangement. After 24 h of treatment, media was collected for quantification of reactive oxygen species (ROS) and very low-density lipoprotein (VLDL), and cell lysates were collected for quantification of gene expression. No interactions were detected between CC, DLM, or FA. Both CC and DLM decreased the expression of methionine adenosyltransferase 1A (MAT1A). Increasing CC did not alter betaine-homocysteine S-methyltranferase (BHMT) but did increase 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR) and methylenetetrahydrofolate reductase (MTHFR) expression. Increasing DLM decreased expression of BHMT and MTR, but did not affect MTHFR. Expression of both phosphatidylethanolamine N-methyltransferase (PEMT) and microsomal triglyceride transfer protein (MTTP) were decreased by increasing CC and DLM, while carnitine palmitoyltransferase 1A (CPT1A) was unaffected by either. Treatment with FA decreased the expression of MAT1A, MTR, MTHFR and tended to decrease PEMT but did not affect BHMT and MTTP. Treatment with FA increased CPT1A expression. Increasing CC increased secretion of VLDL and decreased the accumulation of ROS in media. Within neonatal bovine hepatocytes, choline and methionine differentially regulate methyl carbon pathways and suggest that choline may play a critical role in

Glycogen synthase from the parabasalian parasite Trichomonas vaginalis: An unusual member of the starch/glycogen synthase family.

Science.gov (United States)

Wilson, Wayne A; Pradhan, Prajakta; Madhan, Nayasha; Gist, Galen C; Brittingham, Andrew

2017-07-01

Trichomonas vaginalis, a parasitic protist, is the causative agent of the common sexually-transmitted infection trichomoniasis. The organism has long been known to synthesize substantial glycogen as a storage polysaccharide, presumably mobilizing this compound during periods of carbohydrate limitation, such as might be encountered during transmission between hosts. However, little is known regarding the enzymes of glycogen metabolism in T. vaginalis. We had previously described the identification and characterization of two forms of glycogen phosphorylase in the organism. Here, we measure UDP-glucose-dependent glycogen synthase activity in cell-free extracts of T. vaginalis. We then demonstrate that the TVAG_258220 open reading frame encodes a glycosyltransferase that is presumably responsible for this synthetic activity. We show that expression of TVAG_258220 in a yeast strain lacking endogenous glycogen synthase activity is sufficient to restore glycogen accumulation. Furthermore, when TVAG_258220 is expressed in bacteria, the resulting recombinant protein has glycogen synthase activity in vitro, transferring glucose from either UDP-glucose or ADP-glucose to glycogen and using both substrates with similar affinity. This protein is also able to transfer glucose from UDP-glucose or ADP-glucose to maltose and longer oligomers of glucose but not to glucose itself. However, with these substrates, there is no evidence of processivity and sugar transfer is limited to between one and three glucose residues. Taken together with our earlier work on glycogen phosphorylase, we are now well positioned to define both how T. vaginalis synthesizes and utilizes glycogen, and how these processes are regulated. Copyright © 2017 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

In vitro biochemical characterization of all barley endosperm starch synthases

DEFF Research Database (Denmark)

Cuesta-Seijo, Jose A.; Nielsen, Morten M.; Ruzanski, Christian

2016-01-01

Starch is the main storage polysaccharide in cereals and the major source of calories in the human diet. It is synthesized by a panel of enzymes including five classes of starch synthases (SSs). While the overall starch synthase (SS) reaction is known, the functional differences between the five SS....... Here we provide a detailed biochemical study of the activity of all five classes of SSs in barley endosperm. Each enzyme was produced recombinantly in E. coli and the properties and modes of action in vitro were studied in isolation from other SSs and other substrate modifying activities. Our results...... define the mode of action of each SS class in unprecedented detail; we analyze their substrate selection, temperature dependence and stability, substrate affinity and temporal abundance during barley development. Our results are at variance with some generally accepted ideas about starch biosynthesis...

Nonnatural amino acid incorporation into the methionine 214 position of the metzincin Pseudomonas aeruginosa alkaline protease

Directory of Open Access Journals (Sweden)

Honek John F

2005-10-01

Full Text Available Abstract Background The alkaline protease from Pseudomonas aeruginosa (AprA is a member of the metzincin superfamily of metalloendoproteases. A key feature of these proteases is a conserved methionine-containing 1,4-tight β turn at the base of the active site zinc binding region. Results To explore the invariant methionine position in this class of protease, incorporation of a nonnatural fluorinated methionine, L-difluoromethionine (DFM, into this site was accomplished. Although overproduction of the N-terminal catalytic fragment of AprA resulted in protein aggregates which could not be resolved, successful heterologous production of the entire AprA was accomplished in the presence and absence of the nonnatural amino acid. DFM incorporation was found to only slightly alter the enzyme kinetics of AprA. In addition, differential scanning calorimetry indicated no significant alteration in the thermal stability of the modified enzyme. Conclusion Although invariant in all metzincin proteases, the methionine 214 position in AprA can be successfully replaced by the nonnatural amino acid DFM resulting in little effect on protein structure and function. This study indicates that the increased size of the methyl group by the introduction of two fluorines is still sufficiently non-sterically demanding, and bodes well for the application of DFM to biophysical studies of protein structure and function in this class of protease.

Nonnatural amino acid incorporation into the methionine 214 position of the metzincin Pseudomonas aeruginosa alkaline protease

Science.gov (United States)

Walasek, Paula; Honek, John F

2005-01-01

Background The alkaline protease from Pseudomonas aeruginosa (AprA) is a member of the metzincin superfamily of metalloendoproteases. A key feature of these proteases is a conserved methionine-containing 1,4-tight β turn at the base of the active site zinc binding region. Results To explore the invariant methionine position in this class of protease, incorporation of a nonnatural fluorinated methionine, L-difluoromethionine (DFM), into this site was accomplished. Although overproduction of the N-terminal catalytic fragment of AprA resulted in protein aggregates which could not be resolved, successful heterologous production of the entire AprA was accomplished in the presence and absence of the nonnatural amino acid. DFM incorporation was found to only slightly alter the enzyme kinetics of AprA. In addition, differential scanning calorimetry indicated no significant alteration in the thermal stability of the modified enzyme. Conclusion Although invariant in all metzincin proteases, the methionine 214 position in AprA can be successfully replaced by the nonnatural amino acid DFM resulting in little effect on protein structure and function. This study indicates that the increased size of the methyl group by the introduction of two fluorines is still sufficiently non-sterically demanding, and bodes well for the application of DFM to biophysical studies of protein structure and function in this class of protease. PMID:16221305

Calcium-mediated signaling and calmodulin-dependent kinase regulate hepatocyte-inducible nitric oxide synthase expression.

Science.gov (United States)

Zhang, Baochun; Crankshaw, Will; Nesemeier, Ryan; Patel, Jay; Nweze, Ikenna; Lakshmanan, Jaganathan; Harbrecht, Brian G

2015-02-01

Induced nitric oxide synthase (iNOS) is induced in hepatocytes by shock and inflammatory stimuli. Excessive NO from iNOS mediates shock-induced hepatic injury and death, so understanding the regulation of iNOS will help elucidate the pathophysiology of septic shock. In vitro, cytokines induce iNOS expression through activation of signaling pathways including mitogen-activated protein kinases and nuclear factor κB. Cytokines also induce calcium (Ca(2+)) mobilization and activate calcium-mediated intracellular signaling pathways, typically through activation of calmodulin-dependent kinases (CaMK). Calcium regulates NO production in macrophages but the role of calcium and calcium-mediated signaling in hepatocyte iNOS expression has not been defined. Primary rat hepatocytes were isolated, cultured, and induced to produce NO with proinflammatory cytokines. Calcium mobilization and Ca(2+)-mediated signaling were altered with ionophore, Ca(2+) channel blockers, and inhibitors of CaMK. The Ca(2+) ionophore A23187 suppressed cytokine-stimulated NO production, whereas Ethylene glycol tetraacetic acid and nifedipine increased NO production, iNOS messenger RNA, and iNOS protein expression. Inhibition of CaMK with KN93 and CBD increased NO production but the calcineurin inhibitor FK 506 decreased iNOS expression. These data demonstrate that calcium-mediated signaling regulates hepatocyte iNOS expression and does so through a mechanism independent of calcineurin. Changes in intracellular calcium levels may regulate iNOS expression during hepatic inflammation induced by proinflammatory cytokines. Copyright © 2015 Elsevier Inc. All rights reserved.

Identifying the catalytic components of cellulose synthase and the maize mixed-linkage beta-glucan synthase

Energy Technology Data Exchange (ETDEWEB)

Nicholas C Carpita

2009-04-20

Five specific objectives of this project are to develop strategies to identify the genes that encode the catalytic components of "mixed-linkage" (1→3),(1→4)-beta-D-glucans in grasses, to determine the protein components of the synthase complex, and determine the biochemical mechanism of synthesis. We have used proteomic approaches to define intrinsic and extrinsic polypeptides of Golgi membranes that are associated with polysaccharide synthesis and trafficking. We were successful in producing recombinant catalytic domains of cellulose synthase genes and discovered that they dimerize upon concentration, indicating that two CesA proteins form the catalytic unit. We characterized a brittle stalk2 mutant as a defect in a COBRA-like protein that results in compromised lignin-cellulose interactions that decrease tissue flexibility. We used virus-induced gene silencing of barley cell wall polysaccharide synthesis by BSMV in an attempt to silence specific members of the cellulose synthase-like gene family. However, we unexpectedly found that regardless of the specificity of the target gene, whole gene interaction networks were silenced. We discovered the cause to be an antisense transcript of the cellulose synthase gene initiated small interfering RNAs that spread silencing to related genes.

1H NMR studies of substrate hydrogen exchange reactions catalyzed by L-methionine gamma-lyase

International Nuclear Information System (INIS)

Esaki, N.; Nakayama, T.; Sawada, S.; Tanaka, H.; Soda, K.

1985-01-01

Hydrogen exchange reactions of various L-amino acids catalyzed by L-methionine gamma-lyase (EC 4.4.1.11) have been studied. The enzyme catalyzes the rapid exchange of the alpha- and beta-hydrogens of L-methionine and S-methyl-L-cysteine with deuterium from the solvent. The rate of alpha-hydrogen exchange was about 40 times faster than that of the enzymatic elimination reaction of the sulfur-containing amino acids. The enzyme also catalyzes the exchange reaction of alpha- and beta-hydrogens of the straight-chain L-amino acids which are not susceptible to elimination. The exchange rates of the alpha-hydrogen and the total beta-hydrogens of L-alanine and L-alpha-aminobutyrate with deuterium followed first-order kinetics. For L-norvaline, L-norleucine, S-methyl-L-cysteine, and L-methionine, the rate of alpha-hydrogen exchange followed first-order kinetics, but the rate of total beta-hydrogen exchange decreased due to a primary isotope effect at the alpha-position. L-Phenylalanine and L-tryptophan slowly underwent alpha-hydrogen exchange. The pro-R hydrogen of glycine was deuterated stereospecifically

Anxiety-related behavior in hyperhomocysteinemia induced by methionine nutritional overload in rats: role of the brain oxidative stress.

Science.gov (United States)

Hrncic, Dragan; Mikić, Jelena; Rasic-Markovic, Aleksandra; Velimirović, Milica; Stojković, Tihomir; Obrenović, Radmila; Rankov-Petrović, Bojana; Šušić, Veselinka; Djuric, Dragan; Petronijević, Nataša; Stanojlovic, Olivera

2016-10-01

The aim of this study was to examine the effects of a methionine-enriched diet on anxiety-related behavior in rats and to determine the role of the brain oxidative status in these alterations. Adult male Wistar rats were fed from the 30th to 60th postnatal day with standard or methionine-enriched diet (double content comparing with standard diet: 7.7 g/kg). Rats were tested in open field and light-dark tests and afterwards oxidative status in the different brain regions were determined. Hyperhomocysteinemia induced by methionine-enriched diet in this study decreased the number of rearings, as well as the time that these animals spent in the center of the open field, but increased index of thigmotaxy. Oxidative status was selectively altered in the examined regions. Lipid peroxidation was significantly increased in the cortex and nc. caudatus of rats developing hyperhomocysteinemia, but unaltered in the hippocampus and thalamus. Based on the results of this research, it could be concluded that hyperhomocysteinemia induced by methionine nutritional overload increased anxiety-related behavior in rats. These proanxiogenic effects could be, at least in part, a consequence of oxidative stress in the rat brain.

Local cerebral metabolic rate of 11C-L-Methionine in early stages of dementia, schizophrenia, Parkinson's disease

International Nuclear Information System (INIS)

Bustany, P.; Henry, J.F.; de Rotrou, J.; Signoret, J.L.; Ziegler, M.; Zarifian, E.; Soussaline, F.; Comar, D.

1983-06-01

A dynamic three-compartment model of methionine metabolism in brain was applied in human patients using 11 C-L-Methionine and positron emission tomography (P.E.T). Psychometric evaluations of demented patients were correlated with a significant diminution of protein synthesis in the frontal area. This diminution was lower in ebephrenic patients (-17%) but was consistent with the results obtained with 18 F glucose. No significant abnormality was detected in patients with Parkinson disease

Sesquiterpene Synthase-3-Hydroxy-3-Methylglutaryl Coenzyme A Synthase Fusion Protein Responsible for Hirsutene Biosynthesis in Stereum hirsutum.

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Flynn, Christopher M; Schmidt-Dannert, Claudia

2018-06-01

The wood-rotting mushroom Stereum hirsutum is a known producer of a large number of namesake hirsutenoids, many with important bioactivities. Hirsutenoids form a structurally diverse and distinct class of sesquiterpenoids. No genes involved in hirsutenoid biosynthesis have yet been identified or their enzymes characterized. Here, we describe the cloning and functional characterization of a hirsutene synthase as an unexpected fusion protein of a sesquiterpene synthase (STS) with a C-terminal 3-hydroxy-3-methylglutaryl-coenzyme A (3-hydroxy-3-methylglutaryl-CoA) synthase (HMGS) domain. Both the full-length fusion protein and truncated STS domain are highly product-specific 1,11-cyclizing STS enzymes with kinetic properties typical of STSs. Complementation studies in Saccharomyces cerevisiae confirmed that the HMGS domain is also functional in vivo Phylogenetic analysis shows that the hirsutene synthase domain does not form a clade with other previously characterized sesquiterpene synthases from Basidiomycota. Comparative gene structure analysis of this hirsutene synthase with characterized fungal enzymes reveals a significantly higher intron density, suggesting that this enzyme may be acquired by horizontal gene transfer. In contrast, the HMGS domain is clearly related to other fungal homologs. This STS-HMGS fusion protein is part of a biosynthetic gene cluster that includes P450s and oxidases that are expressed and could be cloned from cDNA. Finally, this unusual fusion of a terpene synthase to an HMGS domain, which is not generally recognized as a key regulatory enzyme of the mevalonate isoprenoid precursor pathway, led to the identification of additional HMGS duplications in many fungal genomes, including the localization of HMGSs in other predicted sesquiterpenoid biosynthetic gene clusters. IMPORTANCE Hirsutenoids represent a structurally diverse class of bioactive sesquiterpenoids isolated from fungi. Identification of their biosynthetic pathways will provide

Impact of methionine oxidation on calmodulin structural dynamics

Energy Technology Data Exchange (ETDEWEB)

McCarthy, Megan R.; Thompson, Andrew R.; Nitu, Florentin [Biochemistry, Molecular Biology and Biophysics Department, University of Minnesota, Minneapolis, MN 55455 (United States); Moen, Rebecca J. [Chemistry and Geology Department, Minnesota State University, Mankato, MN 56001 (United States); Olenek, Michael J. [Biology Department, University of Wisconsin, La Crosse, WI 54601 (United States); Klein, Jennifer C., E-mail: jklein@uwlax.edu [Biology Department, University of Wisconsin, La Crosse, WI 54601 (United States); Thomas, David D., E-mail: ddt@umn.edu [Biochemistry, Molecular Biology and Biophysics Department, University of Minnesota, Minneapolis, MN 55455 (United States)

2015-01-09

Highlights: • We measured the distance distribution between two spin labels on calmodulin by DEER. • Two structural states, open and closed, were resolved at both low and high Ca. • Ca shifted the equilibrium toward the open state by a factor of 13. • Methionine oxidation, simulated by glutamine substitution, decreased the Ca effect. • These results have important implications for aging in muscle and other tissues. - Abstract: We have used electron paramagnetic resonance (EPR) to examine the structural impact of oxidizing specific methionine (M) side chains in calmodulin (CaM). It has been shown that oxidation of either M109 or M124 in CaM diminishes CaM regulation of the muscle calcium release channel, the ryanodine receptor (RyR), and that mutation of M to Q (glutamine) in either case produces functional effects identical to those of oxidation. Here we have used site-directed spin labeling and double electron–electron resonance (DEER), a pulsed EPR technique that measures distances between spin labels, to characterize the structural changes resulting from these mutations. Spin labels were attached to a pair of introduced cysteine residues, one in the C-lobe (T117C) and one in the N-lobe (T34C) of CaM, and DEER was used to determine the distribution of interspin distances. Ca binding induced a large increase in the mean distance, in concert with previous X-ray crystallography and NMR data, showing a closed structure in the absence of Ca and an open structure in the presence of Ca. DEER revealed additional information about CaM’s structural heterogeneity in solution: in both the presence and absence of Ca, CaM populates both structural states, one with probes separated by ∼4 nm (closed) and another at ∼6 nm (open). Ca shifts the structural equilibrium constant toward the open state by a factor of 13. DEER reveals the distribution of interprobe distances, showing that each of these states is itself partially disordered, with the width of each

Mutational analysis of Sep-tRNA:Cys-tRNA synthase reveals critical residues for tRNA-dependent cysteine formation.

Science.gov (United States)

Helgadóttir, Sunna; Sinapah, Sylvie; Söll, Dieter; Ling, Jiqiang

2012-01-02

In methanogenic archaea, Sep-tRNA:Cys-tRNA synthase (SepCysS) converts Sep-tRNA(Cys) to Cys-tRNA(Cys). The mechanism of tRNA-dependent cysteine formation remains unclear due to the lack of functional studies. In this work, we mutated 19 conserved residues in Methanocaldococcus jannaschii SepCysS, and employed an in vivo system to determine the activity of the resulting variants. Our results show that three active-site cysteines (Cys39, Cys42 and Cys247) are essential for SepCysS activity. In addition, combined with structural modeling, our mutational and functional analyses also reveal multiple residues that are important for the binding of PLP, Sep and tRNA. Our work thus represents the first systematic functional analysis of conserved residues in archaeal SepCysSs, providing insights into the catalytic and substrate binding mechanisms of this poorly characterized enzyme. Copyright © 2011 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Hydroxychavicol, a Piper betle leaf component, induces apoptosis of CML cells through mitochondrial reactive oxygen species-dependent JNK and endothelial nitric oxide synthase activation and overrides imatinib resistance.

Science.gov (United States)

Chakraborty, Jayashree B; Mahato, Sanjit K; Joshi, Kalpana; Shinde, Vaibhav; Rakshit, Srabanti; Biswas, Nabendu; Choudhury Mukherjee, Indrani; Mandal, Labanya; Ganguly, Dipyaman; Chowdhury, Avik A; Chaudhuri, Jaydeep; Paul, Kausik; Pal, Bikas C; Vinayagam, Jayaraman; Pal, Churala; Manna, Anirban; Jaisankar, Parasuraman; Chaudhuri, Utpal; Konar, Aditya; Roy, Siddhartha; Bandyopadhyay, Santu

2012-01-01

Alcoholic extract of Piper betle (Piper betle L.) leaves was recently found to induce apoptosis of CML cells expressing wild type and mutated Bcr-Abl with imatinib resistance phenotype. Hydroxy-chavicol (HCH), a constituent of the alcoholic extract of Piper betle leaves, was evaluated for anti-CML activity. Here, we report that HCH and its analogues induce killing of primary cells in CML patients and leukemic cell lines expressing wild type and mutated Bcr-Abl, including the T315I mutation, with minimal toxicity to normal human peripheral blood mononuclear cells. HCH causes early but transient increase of mitochondria-derived reactive oxygen species. Reactive oxygen species-dependent persistent activation of JNK leads to an increase in endothelial nitric oxide synthase-mediated nitric oxide generation. This causes loss of mitochondrial membrane potential, release of cytochrome c from mitochondria, cleavage of caspase 9, 3 and poly-adenosine diphosphate-ribose polymerase leading to apoptosis. One HCH analogue was also effective in vivo in SCID mice against grafts expressing the T315I mutation, although to a lesser extent than grafts expressing wild type Bcr-Abl, without showing significant bodyweight loss. Our data describe the role of JNK-dependent endothelial nitric oxide synthase-mediated nitric oxide for anti-CML activity of HCH and this molecule merits further testing in pre-clinical and clinical settings. © 2011 Japanese Cancer Association.

The enzymatic activities of brain catechol-O-methyltransferase (COMT) and methionine sulphoxide reductase are correlated in a COMT Val/Met allele-dependent fashion.

Science.gov (United States)

Moskovitz, Jackob; Walss-Bass, Consuelo; Cruz, Dianne A; Thompson, Peter M; Hairston, Jenaqua; Bortolato, Marco

2015-12-01

The enzyme catechol-O-methyltransferase (COMT) plays a primary role in the metabolism of catecholamine neurotransmitters and is implicated in the modulation of cognitive and emotional responses. The best characterized single nucleotide polymorphism (SNP) of the COMT gene consists of a valine (Val)-to-methionine (Met) substitution at codon 108/158. The Met-containing variant confers a marked reduction in COMT catalytic activity. We recently showed that the activity of recombinant COMT is positively regulated by the enzyme Met sulphoxide reductase (MSR), which counters the oxidation of Met residues of proteins. The current study was designed to assess whether brain COMT activity may be correlated to MSR in an allele-dependent fashion. COMT and MSR activities were measured from post-mortem samples of prefrontal cortices, striata and cerebella of 32 subjects by using catechol and dabsyl-Met sulphoxide as substrates, respectively. Allelic discrimination of COMT Val(108/185) Met SNP was performed using the Taqman 5'nuclease assay. Our studies revealed that, in homozygous carriers of Met, but not Val alleles, the activity of COMT and MSR was significantly correlated throughout all tested brain regions. These results suggest that the reduced enzymatic activity of Met-containing COMT may be secondary to Met sulphoxidation and point to MSR as a key molecular determinant for the modulation of COMT activity. © 2015 British Neuropathological Society.

Structural Transitions Induced by a Recombinant Methionine-Trigger in Silk Spidroin

Science.gov (United States)

Wilson, Donna; Winkler, Stefan; Valluzzi, Regina; Kaplan, David

2000-03-01

Control of beta sheet formation is an important factor in the understanding and prediction of structural transitions and protein folding. In genetically engineered silk proteins this control has been achieved using oxidative triggers. A genetically engineered variant of a spider silk protein, and a peptide analog, based on the consensus sequence of Nephila clavipes dragline silk, were modified to include methionines flanking the beta sheet forming polyalanine regions. These methionines could be selectively reduced and oxidized, altering the bulkiness and charge of the sulfhydryl group to control beta sheet formation by steric hindrance. Biophysical characterization and monitoring of structural transitions and intermediates were accomplished through attenuated total reflectance infrared spectroscopy (ATR-IR) for solution state structures in both oxidized and reduced forms. For solid state structural characterization, IR microscopy and reflectance IR experiments were performed. Electron diffraction data as well as circular dichroism studies provide structural corroboration for all experiments in which reproducible sample preparation was achieved.

Neuroendocrine and Immune Responses Undertake Different Fates following Tryptophan or Methionine Dietary Treatment: Tales from a Teleost Model

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Rita Azeredo

2017-09-01

Full Text Available Methionine and tryptophan appear to be fundamental in specific cellular pathways involved in the immune response mechanisms, including stimulation of T-regulatory cells by tryptophan metabolites or pro-inflammatory effects upon methionine supplementation. Thus, the aim of this study was to evaluate the immunomodulatory effect of these amino acids on the inflammatory and neuroendocrine responses in juveniles of European seabass, Dicentrarchus labrax. To achieve this, goal fish were fed for 14 days methionine and tryptophan-supplemented diets (MET and TRP, respectively, 2× dietary requirement level or a control diet meeting the amino acids requirement levels (CTRL. Fish were sampled for immune status assessment and the remaining fish were challenged with intraperitoneally injected inactivated Photobacterium damselae subsp. piscicida and sampled either 4 or 24 h post-injection. Respiratory burst activity, brain monoamines, plasma cortisol, and immune-related gene expression showed distinct and sometimes opposite patterns regarding the effects of dietary amino acids. While neuroendocrine intermediates were not affected by any dietary treatment at the end of the feeding trial, both supplemented diets led to increased levels of plasma cortisol after the inflammatory insult, while brain monoamine content was higher in TRP-fed fish. Peripheral blood respiratory burst was higher in TRP-fed fish injected with the bacteria inoculum but only compared to those fed MET. However, no changes were detected in total antioxidant capacity. Complement factor 3 was upregulated in MET-fed fish but methionine seemed to poorly affect other genes expression patterns. In contrast, fish fed MET showed increased immune cells numbers both before and after immune challenge, suggesting a strong enhancing effect of methionine on immune cells proliferation. Differently, tryptophan effects on inflammatory transcripts suggested an inhibitory mode of action. This, together

11C-methionine PET/CT in 99mTc-sestamibi-negative hyperparathyroidism in patients with renal failure on chronic haemodialysis

International Nuclear Information System (INIS)

Rubello, Domenico; Fanti, Stefano; Nanni, Cristina; Farsad, Mohsen; Castellucci, Paolo; Boschi, Stefano; Franchi, Roberto; Mariani, Giuliano; Fig, Lorraine M.; Gross, Milton D.

2006-01-01

Scintigraphic localisation of parathyroid glands is often unsuccessful in patients with renal failure on chronic haemodialysis who have secondary hyperparathyroidism (HPT). The purpose of this study was to investigate the use of 11 C-methionine PET/CT to detect hyperfunctioning parathyroid glands in patients with renal failure on chronic haemodialysis who had 99m Tc-sestamibi-negative HPT. 11 C-methionine PET/CT was performed in 18 patients (11 women and 7 men, aged 42-79 years; mean age 57.8 years) on haemodialysis for renal failure (2-14 years' duration), with normo-, hypo- or hypercalcaemia and HPT not localised by either dual-tracer 99m Tc-pertechnetate/ 99m Tc-sestamibi subtraction scans or dual-phase 99m Tc-sestamibi scans. In three of ten patients with normo- or hypocalcaemic HPT there was increased 11 C-methionine accumulation in one gland. Seven of eight patients with hypercalcaemic HPT showed increased uptake: in five of these patients increased 11 C-methionine accumulation was present in one gland, while in two it was demonstrated in two glands. All patients also had high-resolution ultrasound of the neck and were treated with subtotal parathyroidectomy, leaving a remnant of the smallest of the four glands. Regardless of their size, all glands with abnormal 11 C-methionine parathyroid uptake were removed, and all demonstrated parathyroid hyperplasia. All patients developed post-parathyroidectomy hypoparathyroidism and one patient with normocalcaemic HPT relapsed 8 months after surgery. These data suggest that 11 C-methionine PET/CT may be used to identify hyperfunctioning parathyroid glands in non-primary HPT, and especially hypercalcaemic HPT, when conventional 99m Tc-sestamibi imaging is non-localising. (orig.)

Clinical significance of Phosphatidyl Inositol Synthase overexpression in oral cancer

International Nuclear Information System (INIS)

Kaur, Jatinder; Sawhney, Meenakshi; DattaGupta, Siddartha; Shukla, Nootan K; Srivastava, Anurag; Ralhan, Ranju

2010-01-01

We reported increased levels of Phosphatidyl Inositol synthase (PI synthase), (enzyme that catalyses phosphatidyl inositol (PI) synthesis-implicated in intracellular signaling and regulation of cell growth) in smokeless tobacco (ST) exposed oral cell cultures by differential display. This study determined the clinical significance of PI synthase overexpression in oral squamous cell carcinoma (OSCC) and premalignant lesions (leukoplakia), and identified the downstream signaling proteins in PI synthase pathway that are perturbed by smokeless tobacco (ST) exposure. Tissue microarray (TMA) Immunohistochemistry, Western blotting, Confocal laser scan microscopy, RT-PCR were performed to define the expression of PI synthase in clinical samples and in oral cell culture systems. Significant increase in PI synthase immunoreactivity was observed in premalignant lesions and OSCCs as compared to oral normal tissues (p = 0.000). Further, PI synthase expression was significantly associated with de-differentiation of OSCCs, (p = 0.005) and tobacco consumption (p = 0.03, OR = 9.0). Exposure of oral cell systems to smokeless tobacco (ST) in vitro confirmed increase in PI synthase, Phosphatidylinositol 3-kinase (PI3K) and cyclin D1 levels. Collectively, increased PI synthase expression was found to be an early event in oral cancer and a target for smokeless tobacco

SIRT3 deacetylates ATP synthase F1 complex proteins in response to nutrient- and exercise-induced stress.

Science.gov (United States)

Vassilopoulos, Athanassios; Pennington, J Daniel; Andresson, Thorkell; Rees, David M; Bosley, Allen D; Fearnley, Ian M; Ham, Amy; Flynn, Charles Robb; Hill, Salisha; Rose, Kristie Lindsey; Kim, Hyun-Seok; Deng, Chu-Xia; Walker, John E; Gius, David

2014-08-01

Adenosine triphosphate (ATP) synthase uses chemiosmotic energy across the inner mitochondrial membrane to convert adenosine diphosphate and orthophosphate into ATP, whereas genetic deletion of Sirt3 decreases mitochondrial ATP levels. Here, we investigate the mechanistic connection between SIRT3 and energy homeostasis. By using both in vitro and in vivo experiments, we demonstrate that ATP synthase F1 proteins alpha, beta, gamma, and Oligomycin sensitivity-conferring protein (OSCP) contain SIRT3-specific reversible acetyl-lysines that are evolutionarily conserved and bind to SIRT3. OSCP was further investigated and lysine 139 is a nutrient-sensitive SIRT3-dependent deacetylation target. Site directed mutants demonstrate that OSCP(K139) directs, at least in part, mitochondrial ATP production and mice lacking Sirt3 exhibit decreased ATP muscle levels, increased ATP synthase protein acetylation, and an exercise-induced stress-deficient phenotype. This work connects the aging and nutrient response, via SIRT3 direction of the mitochondrial acetylome, to the regulation of mitochondrial energy homeostasis under nutrient-stress conditions by deacetylating ATP synthase proteins. Our data suggest that acetylome signaling contributes to mitochondrial energy homeostasis by SIRT3-mediated deacetylation of ATP synthase proteins.

Topoisomerase 1 Inhibition Promotes Cyclic GMP-AMP Synthase-Dependent Antiviral Responses

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Geneviève Pèépin

2017-10-01

Full Text Available Inflammatory responses, while essential for pathogen clearance, can also be deleterious to the host. Chemical inhibition of topoisomerase 1 (Top1 by low-dose camptothecin (CPT can suppress transcriptional induction of antiviral and inflammatory genes and protect animals from excessive and damaging inflammatory responses. We describe the unexpected finding that minor DNA damage from topoisomerase 1 inhibition with low-dose CPT can trigger a strong antiviral immune response through cyclic GMP-AMP synthase (cGAS detection of cytoplasmic DNA. This argues against CPT having only anti-inflammatory activity. Furthermore, expression of the simian virus 40 (SV40 large T antigen was paramount to the proinflammatory antiviral activity of CPT, as it potentiated cytoplasmic DNA leakage and subsequent cGAS recruitment in human and mouse cell lines. This work suggests that the capacity of Top1 inhibitors to blunt inflammatory responses can be counteracted by viral oncogenes and that this should be taken into account for their therapeutic development.

Regulation of RNA-dependent RNA polymerase 1 and isochorismate synthase gene expression in Arabidopsis.

Directory of Open Access Journals (Sweden)

Lydia J R Hunter

Full Text Available RNA-dependent RNA polymerases (RDRs function in anti-viral silencing in Arabidopsis thaliana and other plants. Salicylic acid (SA, an important defensive signal, increases RDR1 gene expression, suggesting that RDR1 contributes to SA-induced virus resistance. In Nicotiana attenuata RDR1 also regulates plant-insect interactions and is induced by another important signal, jasmonic acid (JA. Despite its importance in defense RDR1 regulation has not been investigated in detail.In Arabidopsis, SA-induced RDR1 expression was dependent on 'NON-EXPRESSER OF PATHOGENESIS-RELATED GENES 1', indicating regulation involves the same mechanism controlling many other SA- defense-related genes, including pathogenesis-related 1 (PR1. Isochorismate synthase 1 (ICS1 is required for SA biosynthesis. In defensive signal transduction RDR1 lies downstream of ICS1. However, supplying exogenous SA to ics1-mutant plants did not induce RDR1 or PR1 expression to the same extent as seen in wild type plants. Analysing ICS1 gene expression using transgenic plants expressing ICS1 promoter:reporter gene (β-glucuronidase constructs and by measuring steady-state ICS1 transcript levels showed that SA positively regulates ICS1. In contrast, ICS2, which is expressed at lower levels than ICS1, is unaffected by SA. The wound-response hormone JA affects expression of Arabidopsis RDR1 but jasmonate-induced expression is independent of CORONATINE-INSENSITIVE 1, which conditions expression of many other JA-responsive genes. Transiently increased RDR1 expression following tobacco mosaic virus inoculation was due to wounding and was not a direct effect of infection. RDR1 gene expression was induced by ethylene and by abscisic acid (an important regulator of drought resistance. However, rdr1-mutant plants showed normal responses to drought.RDR1 is regulated by a much broader range of phytohormones than previously thought, indicating that it plays roles beyond those already suggested in virus

The feasibility of 11C-methionine-PET in diagnosis of solitary lung nodules/masses when compared with 18F-FDG-PET

International Nuclear Information System (INIS)

Hsieh Hungjen; Lin Shenghsiang; Lin Kohan; Lee Chienying; Chang Chengpei; Wang Shyhjen

2008-01-01

The objective of this study was to differentiate between benign and malignant lesions of the lung, 18 F-fluorodeoxyglucose positron emission tomography ( 18 F-FDG-PET) has limitations such as a lower specificity in cases of non-specific inflammation. The positive predictive value is unsatisfactory in countries where inflammatory lung disorders are prevalent. We present the preliminary results of the usefulness of combining 11 C-methionine-PET and 18 F-FDG-PET in this context. Fifteen patients with indeterminate solitary pulmonary nodules/masses (10 men, 5 women; average age 64.7±14.0 years, ranging from 25 to 87 years) were studied using 11 C-methionine- and 18 F-FDG-PET. Interpretations were primarily made on visual analysis with five-point scale and a consensus of two nuclear medicine physicians, using standardized uptake value as an accessory reference. Foci of abnormal radiotracer uptake were subsequently correlated with clinical follow-up, imaging modalities such as chest radiography, chest computed tomography (CT), serial PET studies, and pathology results from bronchoscopic biopsy and/or surgical specimen. Diagnoses were established in 14 patients. The 11 C-methionine-PET and 18 F-FDG-PET studies were both true positive in two cases of adenocarcinoma and true negative in two cases of clinical benign nodules. In one case of lymphoid hyperplasia both 11 C-methionine-PET and 18 F-FDG-PET showed false-positive findings. Discordant results were obtained in nine cases. In spite of the false-positive results of 18 F-FDG-PET, 11 C-methionine-PET was true negative in four cases with chronic inflammatory nodules and three cases of pulmonary tuberculosis. Furthermore, 11 C-methionine-PET was true positive in one case of lung metastasis of thyroid cancer, and in another with recurrence of gastric cancer, respectively, for which 18 F-FDG-PET imaging was false negative. Our experience indicates that 11 C-methionine-PET seems more specific and sensitive when compared with

Expression of inducible nitric oxide synthase in endotoxemic rat hepatocytes is dependent on the cellular glutathione status

NARCIS (Netherlands)

Vos, TA; van Goor, H; Tuyt, L; de Jager-Krikken, A; Leuvenink, R; Kuipers, F; Jansen, PLM; Moshage, H

The inducible nitric oxide synthase (iNOS) promoter contains nuclear factor kappa B (NF-kappa B) binding sites. NF-kappa B activation is determined, in part, by the intracellular redox status, The aim of this study was to determine the importance of the cellular glutathione status in relation to

Overexpression of Farnesyl Diphosphate Synthase in Arabidopsis Mitochondria Triggers Light-dependent Lesion Formation and Alters Cytokinin Homeostasis

Czech Academy of Sciences Publication Activity Database

Manzano, D.; Busquets, A.; Closa, M.; Hoyerová, Klára; Schaller, H.; Kamínek, Miroslav; Arró, M.; Ferrer, A.

2006-01-01

Roč. 61, 1-2 (2006), s. 195-213 ISSN 0167-4412 R&D Projects: GA AV ČR(CZ) IAA600380507 Institutional research plan: CEZ:AV0Z50380511 Keywords : Arabidopsis thaliana * cytokinin * farnesyl diphosphate synthase * isoprenoid Subject RIV: EF - Botanics Impact factor: 3.577, year: 2006

Identification of UDPG-binding polypeptides and purified (1,3)-β-glucan synthase by photoaffinity labelling with 5-azido-UDPG

International Nuclear Information System (INIS)

Frost, D.J.; Wu, A.; Read, S.M.; Wasserman, B.P.; Drake, R.R.; Haley, B.E.

1989-01-01

The photoaffinity probe 5-azido-uridine 5'-β-[ 32 P]-diphosphate glucose was used to identify the major UDPG-binding polypeptide of red beet (1,3)-β-glucan synthase. Glucan synthase was purified from plasma membranes by sequential solubilization with CHAPS followed by product entrapment. Two major polypeptides at 72 and 54 kD were labelled by probe. Labelling of both was abolished with increasing levels of cold UDPG. However, labelling of the 54 kD polypeptide was dependent upon the presence of divalent cations. These data suggest that the 54 kD polypeptide is a substrate-binding and cation-regulated component of the glucan synthase complex

Hydrogen sulfide-mediated regulation of contractility in the mouse ileum with electrical stimulation: roles of L-cysteine, cystathionine β-synthase, and K+ channels.

Science.gov (United States)

Yamane, Satoshi; Kanno, Toshio; Nakamura, Hiroyuki; Fujino, Hiromichi; Murayama, Toshihiko

2014-10-05

Hydrogen sulfide (H2S) is considered to be a signaling molecule. The precise mechanisms underlying H2S-related events, including the producing enzymes and target molecules in gastrointestinal tissues, have not been elucidated in detail. We herein examined the involvement of H2S in contractions induced by repeated electrical stimulations (ES). ES-induced contractions were neurotoxin-sensitive and increased by aminooxyacetic acid, an inhibitor of cystathionine β-synthase (CBS) and cystathionine γ-lyase, but not by D,L-propargylglycine, a selective inhibitor of cystathionine γ-lyase, in an ES trial-dependent manner. ES-induced contractions were markedly decreased in the presence of L-cysteine. This response was inhibited by aminooxyacetic acid and an antioxidant, and accelerated by L-methionine, an activator of CBS. The existence of CBS was confirmed. NaHS transiently inhibited ES- and acetylcholine-induced contractions, and sustainably decreased basal tone for at least 20 min after its addition. The treatment with glibenclamide, an ATP-sensitive K+ channel blocker, reduced both the L-cysteine response and NaHS-induced inhibition of contractions. The NaHS-induced decrease in basal tone was inhibited by apamin, a small conductance Ca2+-activated K+ channel blocker. These results suggest that H2S may be endogenously produced via CBS in ES-activated enteric neurons, and regulates contractility via multiple K+ channels in the ileum. Copyright © 2014 Elsevier B.V. All rights reserved.

The effect of amino acid lysine and methionine addition on feed toward the growth and retention on mud crab (Scylla serrata)

Science.gov (United States)

Alissianto, Y. R.; Sandriani, Z. A.; Rahardja, B. S.; Agustono; Rozi

2018-04-01

High market demand of mud crab (Scylla serrata) encourages farmers to increase the production of mud crab. However, mud crab can not synthesize essential amino acids, so it is necessary to supply essential amino acids such as lysine and methionine in the diet. This study aims to determine the effect of lysine and methionine on feeds to increase growth and retention of mud crabs (Scylla serrata). In this study the amount of lysine amino acid and methionine added to the trash fish diet were: P0 (0: 0%); P1 (0.75: 0.75%); P2 (1: 1%); P3 (1.25: 1.25%); P4 (1.5: 1.5%) with the ratio of lysine and methionine 1: 1. The parameters observed in this study were Survival Rate (SR), Specific Growth Rate (SGR), Feed Conversion Ratio (FCR), Efficiency Feed (EF), protein retention and energy retention. The results of the 35-day maintenance study showed significant differences (P protein retention and no significant effect (P> 0.05) on energy retention and Survival Rate (SR) on mud crab. The best results in this study were found in P4 treatment with addition of lysine amino acids and methionine (1.5: 1.5%).

Effects of gamma-radiation on some components of food and agricultural products (pyridoxine, folic acid, methionine)

International Nuclear Information System (INIS)

Gehlehtseanu, I.

1974-01-01

the effects of gamma radiation on individual components of food and agricultural products (Pyridoxine, folic acid, methionine) were investigated. Some of the studies have provided support for the hypothesis that the structural changes occurring in separately irradiated components of a foodstuff are greater than those taking place in the same components when present in the foodstuff. Results of irradiating pyridoxine and pyridoxal in an aqueous medium; of folic acid in aqueous solutions and in solid state; and of methionine in aqueous solutions and solid state, are given. (E.T.)

Effect of methionine and cysteine deprivation on growth of different natural isolates of Lactobacillus spp. in chemically defined media

Directory of Open Access Journals (Sweden)

Lozo Jelena

2008-01-01

Full Text Available The purpose of this study was to determine the ability of natural isolates of lactobacilli from different ecological niches to grow in a chemically defined medium in the presence or absence of sulphur-containing amino acids, methionine and/or cysteine. The obtained results indicate that cysteine is essential for growth of L. paracasei subsp. paracasei BGHN14 and BGSJ2-8, while methionine is essential for isolates BGHN40, BGCG31, and BGHV54T of the species L. plantarum. Methionine is also essential for growth of L. rhamnosus BGHV58T. Other analyzed strains, such as L. plantarum BGSJ3-18, BGZB19, BGHV52Ta, and BGHV43T, require the presence of both amino acids for their growth.

Structure of the ent-Copalyl Diphosphate Synthase PtmT2 from Streptomyces platensis CB00739, a Bacterial Type II Diterpene Synthase.

Science.gov (United States)

Rudolf, Jeffrey D; Dong, Liao-Bin; Cao, Hongnan; Hatzos-Skintges, Catherine; Osipiuk, Jerzy; Endres, Michael; Chang, Chin-Yuan; Ma, Ming; Babnigg, Gyorgy; Joachimiak, Andrzej; Phillips, George N; Shen, Ben

2016-08-31

Terpenoids are the largest and most structurally diverse family of natural products found in nature, yet their presence in bacteria is underappreciated. The carbon skeletons of terpenoids are generated through carbocation-dependent cyclization cascades catalyzed by terpene synthases (TSs). Type I and type II TSs initiate cyclization via diphosphate ionization and protonation, respectively, and protein structures of both types are known. Most plant diterpene synthases (DTSs) possess three α-helical domains (αβγ), which are thought to have arisen from the fusion of discrete, ancestral bacterial type I TSs (α) and type II TSs (βγ). Type II DTSs of bacterial origin, of which there are no structurally characterized members, are a missing piece in the structural evolution of TSs. Here, we report the first crystal structure of a type II DTS from bacteria. PtmT2 from Streptomyces platensis CB00739 was verified as an ent-copalyl diphosphate synthase involved in the biosynthesis of platensimycin and platencin. The crystal structure of PtmT2 was solved at a resolution of 1.80 Å, and docking studies suggest the catalytically active conformation of geranylgeranyl diphosphate (GGPP). Site-directed mutagenesis confirmed residues involved in binding the diphosphate moiety of GGPP and identified DxxxxE as a potential Mg(2+)-binding motif for type II DTSs of bacterial origin. Finally, both the shape and physicochemical properties of the active sites are responsible for determining specific catalytic outcomes of TSs. The structure of PtmT2 fundamentally advances the knowledge of bacterial TSs, their mechanisms, and their role in the evolution of TSs.

Mechanisms of suppression of inducible nitric oxide synthase (iNOS) expression in RAW 264.7 cells by andrographolide

Science.gov (United States)

Chiou, Wen-Fei; Chen, Chieh-Fu; Lin, Jin-Jung

2000-01-01

Andrographolide, an active component found in leaves of Andrographis paniculata, has been reported to exhibit nitric oxide (NO) inhibitory property in endotoxin-stimulated macrophages, however, the detailed mechanisms remain unclear. In the present study we investigated the effect of andrographolide on the expression of inducible NO synthase (iNOS) mRNA, protein, and enzyme activity in RAW 264.7 macrophages stimulated with lipopolysaccharide (LPS) plus interferon-γ (IFN-γ).RAW 264.7 cells stimulated with LPS/IFN-γ activated NO production; in this condition andrographolide (1–100 μM) inhibited NO production in a dose-dependent manner with an IC50 value of 17.4±1.1 μM. Andrographolide also reduces the expression of iNOS protein level but without a significant effect on iNOS mRNA. The reduction of iNOS activity is thought to be caused by decreased expression of iNOS protein.In a protein stability assay, andrographolide moderately but significantly reduced the amount of iNOS protein as suggested by accelerating degradation. Furthermore, andrographolide also inhibited total protein de novo synthesis as demonstrated by [35S]-methionine incorporation.As a whole, these data suggest that andrographolide inhibits NO synthesis in RAW 264.7 cells by reducing the expression of iNOS protein and the reduction could occur through two additional mechanisms: prevention of the de novo protein synthesis and decreasing the protein stability via a post-transcriptional mechanism. It is also possible that inhibition of iNOS protein expression and NO production under immune stimulation and/or bacteria infection may explain, in part, the beneficial effects of andrographolide as an anti-inflammatory agent. PMID:10780958

The time-dependent effect of provinolsTM on brain NO synthase activity in L-NAME-induced hypertension

Czech Academy of Sciences Publication Activity Database

Jendeková, L.; Kojšová, S.; Andriantsitohaina, R.; Pecháňová, Olga

2006-01-01

Roč. 55, č. S1 (2006), S31-S37 ISSN 0862-8408 Grant - others:VEGA(SK) 2/6148/26; VEGA(SK) 1/342906 Institutional research plan: CEZ:AV0Z50110509 Keywords : red wine polyphenols * oxidative damage * nitric oxide synthase Subject RIV: ED - Physiology Impact factor: 2.093, year: 2006

Haematological and Serum Biochemical Parameters of Broiler Chickens Fed Varying Dietary Levels of Fermented Castor Oil Seed Meal (Ricinus communis L. and Different Methionine Sources in South Western Nigeria

Directory of Open Access Journals (Sweden)

Ayorinde David Adeniran

2017-09-01

Full Text Available In this experiment, the effect of varying dietary levels of fermented castor oil seed meal (FCSM and different methionine sources (DL-methionine and herbal methionine on haematological and serum biochemical parameters of broilers. A total of 240 one-day-old Anak broiler chicks were used in the experiment lasted 56 days. The dietary experiment was laid out as a completely randomized design in a 4 × 2 factorial arrangement consisting of 4 dietary levels of FCSM (0, 50, 100 and 150 g/kg and 2 methionine sources (DL-methionine and herbal methionine. The birds were weighed and randomly distributed into 8 treatments with 3 replicates of 10 birds each. During the starter phase of the experiment, haemoglobin, red blood cell count, mean corpuscular haemoglobin concentration and eosinophil counts were higher (P

Expression of glycogen synthase and phosphofructokinase in muscle from type 1 (insulin-dependent) diabetic patients before and after intensive insulin treatment

DEFF Research Database (Denmark)

Vestergaard, H; Andersen, P H; Lund, S

1994-01-01

The aim of the present study was to determine whether short-term appropriate insulinization of Type 1 (insulin-dependent) diabetic patients in long-term poor glycaemic control (HbA1C > 9.5%) was associated with an adaptive regulation of the activity and gene expression of key proteins in muscle...... glycogen storage and glycolysis: glycogen synthase and phosphofructokinase, respectively. In nine diabetic patients biopsies of quadriceps muscle were taken before and 24-h after intensified insulin therapy and compared to findings in eight control subjects. Subcutaneous injections of rapid acting insulin...... were given at 3-h intervals to improve glycaemic control in diabetic patients (fasting plasma glucose decreased from 20.8 +/- 0.8 to 8.7 +/- 0.8 mmol/l whereas fasting serum insulin increased from 59 +/- 8 to 173 +/- 3 pmol/l). Before intensified insulin therapy, analysis of muscle biopsies from...

EFFECTS OF RUMEN PROTECTED METHIONINE AND VITAMIN B12 ON RBC PARAMETERS OF DAIRY COWS IN EARLY LACTATION

Directory of Open Access Journals (Sweden)

Morteza Safarkhanlou

2016-12-01

Full Text Available To study the effects of rumen-protected methionine and vitamin B12 as well as their interactions on the parameters of red blood cells of dairy cows in early lactation, 16 Holstein cows in early lactation in experiment with randomized complete block design with the 2×2 factorial arrangement used for 42 days. In this experiment, there were four treatments, which in each treatment is placed two cows primi-parous and two cows multi-parous. Treatments included: 1 The group receiving the basal diet, 2 The group receiving the basal diet with vitamin B12 injections, 3 The group receiving the basal diet with rumen-protected methionine, 4 The group receiving the basal diet with vitamin B12 injections and rumen-protected methionine. The results showed that in the use of vitamin B12 and rumen-protected methionine, there is no significant difference between the experimental groups in the number of red blood cells, hemoglobin levels and blood hematocrit. Mean corpuscular (cell volume and mean corpuscular (cell hemoglobin did increase with vitamin B12 supplementation. In a general conclusion, it seems that increasing MCV and MCH may result in improvement in oxygenation and in turn lead to improvement on dry matter intake and milk production.

Metionina mais cistina digestível e relação metionina mais cistina digestível: lisina para codornas japonesas Digestible methionine plus cystine and relation digestible methionine plus cystine: lysine for japanese quails

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Julio Francisco Valiati Marin

2011-09-01

Full Text Available Objetivou-se determinar o melhor nível de metionina mais cistina digestível e a melhor relação metionina mais cistina digestível:lisina digestível em diferentes níveis de proteína para codorna em postura. Foram utilizadas 400 codornas japonesas produtoras de ovos de consumo com 45 dias de idade, em delineamento inteiramente casualizado, num esquema fatorial 2 x 5, dois níveis de proteína bruta (19,5% e 21,5% e cinco níveis de metionina mais cistina digestível (0,60%; 0,67%; 0,74%; 0,81% e 0,88%, com cinco repetições e oito aves por unidade experimental. Foram analisadas as taxas de postura (%, peso médio dos ovos (g, massa de ovos (g de ovos/ave/dia, consumo de ração (g/ave/dia, conversão alimentar (g de ração/g de ovos, peso e porcentagem de gema (g e %, peso e porcentagem de clara (g e % e peso e porcentagem de casca (g e %. Para o nível de 19,5% de proteína 0,60% de metionina mais cistina digestível e relação metionina mais cistina digestível:lisina digestível de 0,66% foram suficientes para otimizar a produção. Para o nível de 21,5% de proteína 0,851% de metionina mais cistina digestível com relação metionina mais cistina digestível:lisina digestível de 0,935% com consumo diário de 223,3mg/ave levou a uma melhor produção de ovos de codornas.This research had the purpose to determine the best level of digestible methionine plus cystine and the best relation of digestible methionine plus cystine:digestible lysine in different levels of protein for laying Japanese quails. 400 laying Japanese quails, with 45 days of age were used in a completely randomized design, with a factorial 2 x 5, two crude protein levels (19,5% and 21,5% and five levels of digestible methionine plus cystine (0,60%; 0,67%; 0,74%; 0,81% e 0,88%, with five replicates and eight quails per experimental unity. There were analysis of the posture rate (%, egg average weight (g egg mass (egg grams/bird/day, feed intake (g/bird/day, feed

C-11 production with MC-50 cyclotron and synthesis of L-[11C-methyl] methionine

International Nuclear Information System (INIS)

Kim, Sang Wook; Hur, Min Goo; Yang, Seung Dae; Ahn, Soon Hyuk; Chun, Kweon Soo

2003-01-01

L-[ 11 C-methyl] methionine was prepared via no-carrier-added(nca) fast S-alkylation of L-homocysteine with [ 11 C]CH 3 I using solid support (Al 2 O 3 /KF)at room temperature in ethanol. The radiochemical yield of methylation was 90.2%. After reaction, no radiochemical impurity was detected but traces of L-homocysteine precursor were monitored by UV detector. The purification was archived by passing successively through a C 18 and alumina sep-pak. the radiochemical purity of L-[ 11 C-methyl] methionine was over 98% after purification and total elapsed time to prepare was 10min from [ 11 C]CH 3 I delivery

Unchanged gene expression of glycogen synthase in muscle from patients with NIDDM following sulphonylurea-induced improvement of glycaemic control

DEFF Research Database (Denmark)

Vestergaard, H; Lund, S; Bjørbaek, C

1995-01-01

We have previously shown that the mRNA expression of muscle glycogen synthase is decreased in non-insulin-dependent diabetic (NIDDM) patients; the objective of the present protocol was to examine whether the gene expression of muscle glycogen synthase in NIDDM is affected by chronic sulphonylurea...... as enhanced beta-cell responses to an oral glucose load. During euglycaemic, hyperinsulinaemic clamp (2 mU x kg-1 x min-1) in combination with indirect calorimetry, a 35% (p=0.005) increase in whole-body insulin-stimulated glucose disposal rate, predominantly due to an increased non-oxidative glucose....... In conclusion, improved blood glucose control in gliclazide-treated obese NIDDM patients has no impact on the gene expression of muscle glycogen synthase....

Potential role of cysteine and methionine in the protection against hormonal imbalance and mutagenicity induced by furazolidone in female rats

International Nuclear Information System (INIS)

Ahmed, Hanaa H.; El-Aziem, Sekena H. Abd; Abdel-Wahhab, Mosaad A.

2008-01-01

The use of nitrofurans as veterinary drugs has been banned in the EU since 1993 due to doubts on the safety of the protein-bound residues of these drugs in edible products. Furazolidone (FUZ) is a nitrofuran drug, which has been used for many years as an antibacterial drug in veterinary practice. The aim of the current study is to investigate the role of L-cysteine and L-methionine in the protection against hormonal imbalance and the genotoxicity induced by FUZ using the micronucleus (MN) assay and random amplified polymorphism DNA (RAPD-PCR) analysis in female rats. Forty female Sprague-Dawley rats were divided into four groups included the untreated control group; a group treated with FUZ (300 mg/kg b.w.); a group treated with a mixture of L-cysteine (300 mg/kg b.w.) and L-methionine (42.8 mg/kg b.w.) and a group treated with FUZ plus the mixture of L-cysteine and L-methionine for 10 days. The results indicated that FUZ induced hormonal disturbances involving thyroid, ovarian and adrenal hormones. Moreover, FUZ increased the micronucleus formation and induced changes in polymorphic band patterns. The combined treatment with FUZ and the mixture of L-cysteine and L-methionine succeeded to prevent or diminish the endocrine disturbance and the clastogenic effects of FUZ. The current study is casting new light on the complex mechanisms underlying the ameliorating action of dietary L-cysteine and L-methionine against FUZ toxicity in experimental animals

Heterooligomeric phosphoribosyl diphosphate synthase of Saccharomyces cerevisiae

DEFF Research Database (Denmark)

Hove-Jensen, Bjarne

2004-01-01

The yeast Saccharomyces cerevisiae contains five phosphoribosyl diphosphate (PRPP) synthase-homologous genes (PRS1-5), which specify PRPP synthase subunits 1-5. Expression of the five S. cerevisiae PRS genes individually in an Escherichia coli PRPP-less strain (Deltaprs) showed that a single PRS...

Nuclear magnetic resonance studies of amino acids and proteins. Side-chain mobility of methionine in the crystalline amonio acid and in crystallne sperm whale (Physeter catodon) myoglobin

International Nuclear Information System (INIS)

Keniry, M.A.; Rothgeb, T.M.; Smith, R.L.; Gutowsky, H.S.; Oldfield, E.

1983-01-01

Deuterium ( 2 H) nuclear magnetic resonance (NMR) spectra and spin-lattice relaxation times (T 1 ) were obtained of L-[epsilon- 2 H 3 ]methionine, L-[epsilon- 2 H 3 ]methionine in a D,L lattice, and [S-methyl- 2 H 3 ]methionine in the crystalline solid state, as a function of temperature, in addition to obtaining 2 H T 1 and line-width results as a function of temperature on [epsilon- 2 H 3 ]methionine-labeled sperm whale (Physeter catodon) myoglobins by using the method of magnetic ordering. Also recorded were 13 C cross-polarization ''magic-angle'' sample-spinning NMR spectra of [epsilon- 13 C]methionine-labeled crystalline cyanoferrimyoglobin (at 37.7 MHz, corresponding to a magnetic field strength of 3.52 T) and of the same protein in aqueous solution

Flow-based determination of methionine in pharmaceutical formulations exploiting TGA-capped CdTe quantum dots for enhancing the luminol-KIO{sub 4} chemiluminescence

Energy Technology Data Exchange (ETDEWEB)

Zhou, Min, E-mail: mzhou8367@sina.com [Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education, Key Laboratory of Polymer Materials of Gansu Province, Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Wang, Ailian [Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education, Key Laboratory of Polymer Materials of Gansu Province, Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Jiuquan Enviromental Protection Bureau, Jiuquan 735000 (China); Li, Cong; Luo, Xiaowei; Ma, Yongjun [Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education, Key Laboratory of Polymer Materials of Gansu Province, Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China)

2017-03-15

A novel flow-injection chemiluminescence method (FI-CL) was established for the determination of methionine in this paper, based on its strong enhancement on CL intensity of the luminol-KIO{sub 4} system catalyzed by thioglycolic acid-capped CdTe quantum dots in alkaline media. Under the optimized conditions, the relative CL intensity was in proportion to methionine concentration in the range from 1.0×10{sup −8} to 1.0×10{sup −5} g mL{sup −1} with a detection limit of 6.6×10{sup −9} g mL{sup −1} (3σ). The relative standard deviation (RSD) of the CL intensity for 1.0×10{sup −6} g mL{sup −1} standard methionine solution was 0.97% (n=11). The proposed method was successfully applied to determine methionine in commercial pharmaceutical formulations with recoveries between 98.0% and 101.9%. The possible CL mechanism was discussed as well. - Graphical abstract: Methionine in commercial pharmaceutical formulations was determined by flow-injection chemiluminescence and the possible chemiluminescence mechanism was discussed as well.

Local cerebral metabolic rate of /sup 11/C-L-Methionine in early stages of dementia, schizophrenia, Parkinson's disease

Energy Technology Data Exchange (ETDEWEB)

Bustany, P; Henry, J F; de Rotrou, J; Signoret, J L; Ziegler, M; Zarifian, E; Soussaline, F; Comar, D

1983-06-01

A dynamic three-compartment model of methionine metabolism in brain was applied in human patients using /sup 11/C-L-methionine and positron emission tomography (P.E.T). Psychometric evaluations of demented patients were correlated with a significant diminution of protein synthesis in the frontal area. This diminution was lower in ebephrenic patients (-17%) but was consistent with the results obtained with /sup 18/F glucose. No significant abnormality was detected in patients with Parkinson disease.

Isolation and functional characterization of a τ-cadinol synthase, a new sesquiterpene synthase from Lavandula angustifolia.

Science.gov (United States)

Jullien, Frédéric; Moja, Sandrine; Bony, Aurélie; Legrand, Sylvain; Petit, Cécile; Benabdelkader, Tarek; Poirot, Kévin; Fiorucci, Sébastien; Guitton, Yann; Nicolè, Florence; Baudino, Sylvie; Magnard, Jean-Louis

2014-01-01

In this paper we characterize three sTPSs: a germacrene D (LaGERDS), a (E)-β-caryophyllene (LaCARS) and a τ-cadinol synthase (LaCADS). τ-cadinol synthase is reported here for the first time and its activity was studied in several biological models including transiently or stably transformed tobacco species. Three dimensional structure models of LaCADS and Ocimum basilicum γ-cadinene synthase were built by homology modeling using the template structure of Gossypium arboreum δ-cadinene synthase. The depiction of their active site organization provides evidence of the global influence of the enzymes on the formation of τ-cadinol: instead of a unique amino-acid, the electrostatic properties and solvent accessibility of the whole active site in LaCADS may explain the stabilization of the cadinyl cation intermediate. Quantitative PCR performed from leaves and inflorescences showed two patterns of expression. LaGERDS and LaCARS were mainly expressed during early stages of flower development and, at these stages, transcript levels paralleled the accumulation of the corresponding terpene products (germacrene D and (E)-β-caryophyllene). By contrast, the expression level of LaCADS was constant in leaves and flowers. Phylogenetic analysis provided informative results on potential duplication process leading to sTPS diversification in lavender.

A practical and pyrogen-free preparation of 11C-L-methionine in a good manufacturing practice-compliant approach

Directory of Open Access Journals (Sweden)

Kang-Po Li

2017-01-01

Full Text Available Aims: 11C-L-methionine, an amino acid tracer used to delineate certain tumor tissues, has proven to be a prevailing nonfluorodeoxyglucose positron emission tomography (PET radiopharmaceutical. We intended to prepare 11C-L-methionine by following modified synthetic strategies at a rebuilt working area to meet the PET drug current good manufacturing practice (cGMP and Pharmaceutical Inspection Co-operation Scheme (PIC/S regulations. Furthermore, we overcame the problem of pyrogen cross-contamination using a cleaner and more efficient program. Material and Methods: The task of upgrading air filtration equipment was integrated with the set of Web-Based Building Automation system (WebCTRL®. 11C-L-methionine synthesis was carried out in accordance with redesigned methods to meet the requirements of PET drug cGMP. The product quality was tested by a series of quality control tests and was found to be satisfactory. Depyrogenation was carried out by three different methods with different flow rates and flushing durations. The results were examined through limulus amebocyte lysate clotting test. Results: The level of air cleanliness in each section meets the PIC/S GMP standards after the reconstructions. Moreover, after delicate modifications, the radiochemical yield of 11C-L-methionine was 36.20% ± 3.59% (based on 11C-CH3I, n = 7, which is about 10% higher than the average former yield. Besides, the used depyrogenation methods could wipe the bioburden off within 8 h. Conclusions: The modifications done not only offer a good production environment but also protect the products from contamination. The modified approaches in both 11C-L-methionine production and depyrogenation resulted in prominent progress in stability and efficiency as well.

Injectable polypeptide hydrogels via methionine modification for neural stem cell delivery.

Science.gov (United States)

Wollenberg, A L; O'Shea, T M; Kim, J H; Czechanski, A; Reinholdt, L G; Sofroniew, M V; Deming, T J

2018-04-05

Injectable hydrogels with tunable physiochemical and biological properties are potential tools for improving neural stem/progenitor cell (NSPC) transplantation to treat central nervous system (CNS) injury and disease. Here, we developed injectable diblock copolypeptide hydrogels (DCH) for NSPC transplantation that contain hydrophilic segments of modified l-methionine (Met). Multiple Met-based DCH were fabricated by post-polymerization modification of Met to various functional derivatives, and incorporation of different amino acid comonomers into hydrophilic segments. Met-based DCH assembled into self-healing hydrogels with concentration and composition dependent mechanical properties. Mechanical properties of non-ionic Met-sulfoxide formulations (DCH MO ) were stable across diverse aqueous media while cationic formulations showed salt ion dependent stiffness reduction. Murine NSPC survival in DCH MO was equivalent to that of standard culture conditions, and sulfoxide functionality imparted cell non-fouling character. Within serum rich environments in vitro, DCH MO was superior at preserving NSPC stemness and multipotency compared to cell adhesive materials. NSPC in DCH MO injected into uninjured forebrain remained local and, after 4 weeks, exhibited an immature astroglial phenotype that integrated with host neural tissue and acted as cellular substrates that supported growth of host-derived axons. These findings demonstrate that Met-based DCH are suitable vehicles for further study of NSPC transplantation in CNS injury and disease models. Copyright © 2018 Elsevier Ltd. All rights reserved.

Oxidation of methionine by tetraethylammonium chlorochromate in non-aqueous media – A kinetic and mechanistic study

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S. Sheik Mansoor

2015-07-01

Full Text Available The kinetics of oxidation of methionine (Met by tetraethylammonium chlorochromate (TEACC in dimethyl sulfoxide (DMSO leads to the formation of the corresponding sulfoxide. The reaction is first order each in Met and TEACC. The reaction is catalyzed by hydrogen ions. The hydrogen ion dependence has the form : kobs = a + b [H+]. The reaction rate has been determined at different temperatures and activation parameters are calculated. The solvent effect has been analyzed using Kamlet’s multi parametric equation. A correlation of data with Kamlet–Taft solvatochromic parameters (α, β, π∗ suggests that the specific solute–solvent interactions play a major role in governing the reactivity. The reaction does not induce polymerization of acrylonitrile. A suitable mechanism has been proposed.

Adenosine kinase deficiency disrupts the methionine cycle and causes hypermethioninemia, encephalopathy, and abnormal liver function.

Science.gov (United States)

Bjursell, Magnus K; Blom, Henk J; Cayuela, Jordi Asin; Engvall, Martin L; Lesko, Nicole; Balasubramaniam, Shanti; Brandberg, Göran; Halldin, Maria; Falkenberg, Maria; Jakobs, Cornelis; Smith, Desiree; Struys, Eduard; von Döbeln, Ulrika; Gustafsson, Claes M; Lundeberg, Joakim; Wedell, Anna

2011-10-07

Four inborn errors of metabolism (IEMs) are known to cause hypermethioninemia by directly interfering with the methionine cycle. Hypermethioninemia is occasionally discovered incidentally, but it is often disregarded as an unspecific finding, particularly if liver disease is involved. In many individuals the hypermethioninemia resolves without further deterioration, but it can also represent an early sign of a severe, progressive neurodevelopmental disorder. Further investigation of unclear hypermethioninemia is therefore important. We studied two siblings affected by severe developmental delay and liver dysfunction. Biochemical analysis revealed increased plasma levels of methionine, S-adenosylmethionine (AdoMet), and S-adenosylhomocysteine (AdoHcy) but normal or mildly elevated homocysteine (Hcy) levels, indicating a block in the methionine cycle. We excluded S-adenosylhomocysteine hydrolase (SAHH) deficiency, which causes a similar biochemical phenotype, by using genetic and biochemical techniques and hypothesized that there was a functional block in the SAHH enzyme as a result of a recessive mutation in a different gene. Using exome sequencing, we identified a homozygous c.902C>A (p.Ala301Glu) missense mutation in the adenosine kinase gene (ADK), the function of which fits perfectly with this hypothesis. Increased urinary adenosine excretion confirmed ADK deficiency in the siblings. Four additional individuals from two unrelated families with a similar presentation were identified and shown to have a homozygous c.653A>C (p.Asp218Ala) and c.38G>A (p.Gly13Glu) mutation, respectively, in the same gene. All three missense mutations were deleterious, as shown by activity measurements on recombinant enzymes. ADK deficiency is a previously undescribed, severe IEM shedding light on a functional link between the methionine cycle and adenosine metabolism. Copyright © 2011 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Using Raman spectroscopy to understand the origin of the phase transition observed in the crystalline sulfur based amino acid l-methionine

DEFF Research Database (Denmark)

Lima, José A.; Freire, P.T.C.; Melo, F.E.A.

2013-01-01

We present the Raman spectra of l-methionine (C5 H11 NO2 S) monocrystals obtained in the spectral region ranging from 3200 to 50 cm-1 at temperatures from 20 to 375 K. We investigated the dynamics of the different functional groups in l-methionine and related their behaviour to the structural tra...

S-adenosyl-L-methionine protection of acetaminophen mediated oxidative stress and identification of hepatic 4-hydroxynonenal protein adducts by mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Brown, James Mike [Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Huntington, WV (United States); Kuhlman, Christopher [Southwest Environmental Health Sciences Center, Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona Health Sciences Center, Tucson, AZ (United States); Terneus, Marcus V. [Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Huntington, WV (United States); Labenski, Matthew T. [Southwest Environmental Health Sciences Center, Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona Health Sciences Center, Tucson, AZ (United States); Lamyaithong, Andre Benja; Ball, John G. [Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Huntington, WV (United States); Lau, Serrine S. [Southwest Environmental Health Sciences Center, Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona Health Sciences Center, Tucson, AZ (United States); Valentovic, Monica A., E-mail: Valentov@marshall.edu [Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Huntington, WV (United States)

2014-12-01

Acetaminophen (APAP) hepatotoxicity is protected by S-adenosyl-L-methionine (SAMe) treatment 1 hour (h) after APAP in C57/Bl6 mice. This study examined protein carbonylation as well as mitochondrial and cytosolic protein adduction by 4-hydroxynonenal (4-HNE) using mass spectrometry (MS) analysis. Additional studies investigated the leakage of mitochondrial proteins and 4-HNE adduction of these proteins. Male C57/Bl6 mice (n = 5/group) were divided into the following groups and treated as indicated: Veh (15 ml/kg water, ip), SAMe (1.25 mmol/kg, ip), APAP (250 mg/kg), and SAMe given 1 h after APAP (S + A). APAP toxicity was confirmed by an increase (p < 0.05) in plasma ALT (U/l) and liver weight/10 g body weight relative to the Veh, SAMe and S + A groups 4 h following APAP treatment. SAMe administered 1 h post-APAP partially corrected APAP hepatotoxicity as ALT and liver weight/10 g body weights were lower in the S + A group compared the APAP group. APAP induced leakage of the mitochondrial protein, carbamoyl phosphate synthase-1 (CPS-1) into the cytosol and which was reduced in the S + A group. SAMe further reduced the extent of APAP mediated 4-HNE adduction of CPS-1. MS analysis of hepatic and mitochondrial subcellular fractions identified proteins from APAP treated mice. Site specific 4-HNE adducts were identified on mitochondrial proteins sarcosine dehydrogenase and carbamoyl phosphate synthase-1 (CPS-1). In summary, APAP is associated with 4-HNE adduction of proteins as identified by MS analysis and that CPS-1 leakage was greater in APAP treated mice. SAMe reduced the extent of 4-HNE adduction of proteins as well as leakage of CPS-1. - Highlights: • Acetaminophen (APAP) toxicity protected by S-adenosylmethionine (SAMe) • 4-Hydroxynonenal adducted to sarcosine dehydrogenase • 4-Hydroxynonenal adducted to carbamoyl phosphate synthetase-1 • SAMe reduced APAP mediated CPS-1 mitochondrial leakage.

S-adenosyl-L-methionine protection of acetaminophen mediated oxidative stress and identification of hepatic 4-hydroxynonenal protein adducts by mass spectrometry

International Nuclear Information System (INIS)

Brown, James Mike; Kuhlman, Christopher; Terneus, Marcus V.; Labenski, Matthew T.; Lamyaithong, Andre Benja; Ball, John G.; Lau, Serrine S.; Valentovic, Monica A.

2014-01-01

Acetaminophen (APAP) hepatotoxicity is protected by S-adenosyl-L-methionine (SAMe) treatment 1 hour (h) after APAP in C57/Bl6 mice. This study examined protein carbonylation as well as mitochondrial and cytosolic protein adduction by 4-hydroxynonenal (4-HNE) using mass spectrometry (MS) analysis. Additional studies investigated the leakage of mitochondrial proteins and 4-HNE adduction of these proteins. Male C57/Bl6 mice (n = 5/group) were divided into the following groups and treated as indicated: Veh (15 ml/kg water, ip), SAMe (1.25 mmol/kg, ip), APAP (250 mg/kg), and SAMe given 1 h after APAP (S + A). APAP toxicity was confirmed by an increase (p < 0.05) in plasma ALT (U/l) and liver weight/10 g body weight relative to the Veh, SAMe and S + A groups 4 h following APAP treatment. SAMe administered 1 h post-APAP partially corrected APAP hepatotoxicity as ALT and liver weight/10 g body weights were lower in the S + A group compared the APAP group. APAP induced leakage of the mitochondrial protein, carbamoyl phosphate synthase-1 (CPS-1) into the cytosol and which was reduced in the S + A group. SAMe further reduced the extent of APAP mediated 4-HNE adduction of CPS-1. MS analysis of hepatic and mitochondrial subcellular fractions identified proteins from APAP treated mice. Site specific 4-HNE adducts were identified on mitochondrial proteins sarcosine dehydrogenase and carbamoyl phosphate synthase-1 (CPS-1). In summary, APAP is associated with 4-HNE adduction of proteins as identified by MS analysis and that CPS-1 leakage was greater in APAP treated mice. SAMe reduced the extent of 4-HNE adduction of proteins as well as leakage of CPS-1. - Highlights: • Acetaminophen (APAP) toxicity protected by S-adenosylmethionine (SAMe) • 4-Hydroxynonenal adducted to sarcosine dehydrogenase • 4-Hydroxynonenal adducted to carbamoyl phosphate synthetase-1 • SAMe reduced APAP mediated CPS-1 mitochondrial leakage

Role of Ginkgo Biloba in Hyperhomocysteinemia Induced in Rats By L-Methionine and Gamma Irradiation

International Nuclear Information System (INIS)

Mansour, S.Z.

2011-01-01

The objective of this study is to evaluate the role of Ginkgo biloba in hyperhomocysteinemia and oxidative stress. Methionine was supplied orally to adult male albino rats with a dose of 1.7 g/kg/day during 4 weeks. Irradiation was applied to rats by whole body gamma irradiation with a dose of 2 Gy/week up to a total dose of 8 Gy. Ginkgo biloba (100 mg/kg/day) was supplemented orally to rats, daily, during the period of methionine administration and/or radiation exposure. Biochemical analysis in blood and brain tissues showed that methionine and/or gamma irradiation produced significant increases in homocysteine and acetylcholine esterase levels and significant decrease in nitric oxide (NO). Significant increase in malondialdehyde (MDA) with significant decreases in glutathione (GSH), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase levels were observed and alteration in plasma lipid profile was also recorded. Ginkgo biloba supplementation has significantly decreased homocysteine and acetylcholine esterase levels and increased NO while was associated with significant improvement of oxidative stress and lipid profile. It could be concluded that the protective effect of Gingko biloba against hyperhomocysteinemia and oxidative stress is attributed to its antioxidant and free radicals scavenging properties.

Hyperglycemia adversely modulates endothelial nitric oxide synthase during anesthetic preconditioning through tetrahydrobiopterin- and heat shock protein 90-mediated mechanisms.

Science.gov (United States)

Amour, Julien; Brzezinska, Anna K; Jager, Zachary; Sullivan, Corbin; Weihrauch, Dorothee; Du, Jianhai; Vladic, Nikolina; Shi, Yang; Warltier, David C; Pratt, Phillip F; Kersten, Judy R

2010-03-01

Endothelial nitric oxide synthase activity is regulated by (6R-)5,6,7,8-tetrahydrobiopterin (BH4) and heat shock protein 90. The authors tested the hypothesis that hyperglycemia abolishes anesthetic preconditioning (APC) through BH4- and heat shock protein 90-dependent pathways. Myocardial infarct size was measured in rabbits in the absence or presence of APC (30 min of isoflurane), with or without hyperglycemia, and in the presence or absence of the BH4 precursor sepiapterin. Isoflurane-dependent nitric oxide production was measured (ozone chemiluminescence) in human coronary artery endothelial cells cultured in normal (5.5 mm) or high (20 mm) glucose conditions, with or without sepiapterin (10 or 100 microm). APC decreased myocardial infarct size compared with control experiments (26 +/- 6% vs. 46 +/- 3%, respectively; P < 0.05), and this action was blocked by hyperglycemia (43 +/- 4%). Sepiapterin alone had no effect on infarct size (46 +/- 3%) but restored APC during hyperglycemia (21 +/- 3%). The beneficial actions of sepiapterin to restore APC were blocked by the nitric oxide synthase inhibitor N (G)-nitro-L-arginine methyl ester (47 +/- 2%) and the BH4 synthesis inhibitor N-acetylserotonin (46 +/- 3%). Isoflurane increased nitric oxide production to 177 +/- 13% of baseline, and this action was attenuated by high glucose concentrations (125 +/- 6%). Isoflurane increased, whereas high glucose attenuated intracellular BH4/7,8-dihydrobiopterin (BH2) (high performance liquid chromatography), heat shock protein 90-endothelial nitric oxide synthase colocalization (confocal microscopy) and endothelial nitric oxide synthase activation (immunoblotting). Sepiapterin increased BH4/BH2 and dose-dependently restored nitric oxide production during hyperglycemic conditions (149 +/- 12% and 175 +/- 9%; 10 and 100 microm, respectively). The results indicate that tetrahydrobiopterin and heat shock protein 90-regulated endothelial nitric oxide synthase activity play a central

Disruption of Bcchs4, Bcchs6 or Bcchs7 chitin synthase genes in Botrytis cinerea and the essential role of class VI chitin synthase (Bcchs6).

Science.gov (United States)

Morcx, Serena; Kunz, Caroline; Choquer, Mathias; Assie, Sébastien; Blondet, Eddy; Simond-Côte, Elisabeth; Gajek, Karina; Chapeland-Leclerc, Florence; Expert, Dominique; Soulie, Marie-Christine

2013-03-01

Chitin synthases play critical roles in hyphal development and fungal pathogenicity. Previous studies on Botrytis cinerea, a model organism for necrotrophic pathogens, have shown that disruption of Bcchs1 and more particularly Bcchs3a genes have a drastic impact on virulence (Soulié et al., 2003, 2006). In this work, we investigate the role of other CHS including BcCHS4, BcCHS6 and BcCHS7 during the life cycle of B. cinerea. Single deletions of corresponding genes were carried out. Phenotypic analysis indicates that: (i) BcCHS4 enzyme is not essential for development and pathogenicity of the fungus; (ii) BcCHS7 is required for pathogenicity in a host dependant manner. For Bcchs6 gene disruption, we obtained only heterokaryotic strains. Indeed, sexual or asexual purification assays were unsuccessful. We concluded that class VI chitin synthase could be essential for B. cinerea and therefore BcCHS6 represents a valuable antifungal target. Copyright © 2012 Elsevier Inc. All rights reserved.

Macro-and micro-autoradiographic study in comparison with the incorporation of 35S-methionine by various tissue protein in organism

International Nuclear Information System (INIS)

Zhu Shoupeng; Mei Shengping; Le Shangcheng

1990-12-01

The purpose of the study was to observe the incorporation level of 35 S-methionine by various tissue protein in organism. By the use of the macro-and micro-autoradiographic technique, the incorporation of 35 S-methionine by the tissues has been utilized as an index of various tissue protein synthesis. On this basis, the further experiments showed that tracer agent 35 S-methionine was dominantly incorporated in the immature cells of bone marrow and the tissue of liver, kidney and spleen. Its incorporation increased gradually with time. From the experimental results it can be concluded that a strong protein biosynthesis metabolism was produced in these tissues. While the tissues have important physiological function in organism, such as heart, lung and skeletal muscle, but the protein biosynthesis in those tissues was at a low level

Genomic Analysis of Terpene Synthase Family and Functional Characterization of Seven Sesquiterpene Synthases from Citrus sinensis

Directory of Open Access Journals (Sweden)

Berta Alquézar

2017-08-01

Full Text Available Citrus aroma and flavor, chief traits of fruit quality, are derived from their high content in essential oils of most plant tissues, including leaves, stems, flowers, and fruits. Accumulated in secretory cavities, most components of these oils are volatile terpenes. They contribute to defense against herbivores and pathogens, and perhaps also protect tissues against abiotic stress. In spite of their importance, our understanding of the physiological, biochemical, and genetic regulation of citrus terpene volatiles is still limited. The availability of the sweet orange (Citrus sinensis L. Osbeck genome sequence allowed us to characterize for the first time the terpene synthase (TPS family in a citrus type. CsTPS is one of the largest angiosperm TPS families characterized so far, formed by 95 loci from which just 55 encode for putative functional TPSs. All TPS angiosperm families, TPS-a, TPS-b, TPS-c, TPS-e/f, and TPS-g were represented in the sweet orange genome, with 28, 18, 2, 2, and 5 putative full length genes each. Additionally, sweet orange β-farnesene synthase, (Z-β-cubebene/α-copaene synthase, two β-caryophyllene synthases, and three multiproduct enzymes yielding β-cadinene/α-copaene, β-elemene, and β-cadinene/ledene/allo-aromandendrene as major products were identified, and functionally characterized via in vivo recombinant Escherichia coli assays.

Phosphorylation-dependent translocation of glycogen synthase to a novel structure during glycogen resynthesis

DEFF Research Database (Denmark)

Prats, Clara; Cadefau, Joan A; Cussó, Roser

2005-01-01

Glycogen metabolism has been the subject of extensive research, but the mechanisms by which it is regulated are still not fully understood. It is well accepted that the rate-limiting enzymes in glycogenesis and glycogenolysis are glycogen synthase (GS) and glycogen phosphorylase (GPh), respectively....... Both enzymes are regulated by reversible phosphorylation and by allosteric effectors. However, evidence in the literature indicates that changes in muscle GS and GPh intracellular distribution may constitute a new regulatory mechanism of glycogen metabolism. Already in the 1960s, it was proposed...... that glycogen was present in dynamic cellular organelles that were termed glycosomas but no such cellular entities have ever been demonstrated. The aim of this study was to characterize muscle GS and GPh intracellular distribution and to identify possible translocation processes of both enzymes. Using in situ...

L-11C-methionine remote controlled synthetic system

International Nuclear Information System (INIS)

Tomiyoshi, Katsumi; Watanabe, Naoyuki; Tateno, Madoka; Oriuchi, Noboru; Hirano, Tsuneo; Inoue, Tomio; Endo, Keigo

1992-01-01

L- 11 C-methionine have been used clinically in studies of brain tumors in combination with 18 F-fluorodeoxyglucose ( 18 FDG). In respect with synthesizing radiopharmaceuticals, high radioactivity and constant radiochemical yield have to be obtained in routine bases. Therefore automatic synthesis apparatus is inevitable to carry out following points. 1) Radiation Exposure Protection: Half life of 11 C having 20 minutes, starting high radioactivity give a lot of exposure dose to hands and body. 2) Constant radiochemical yield: Amount of radiochemical yield is likely to be varied in manual synthesis which could lead little activity or cancellation to inject. (author)

Caveolin versus calmodulin. Counterbalancing allosteric modulators of endothelial nitric oxide synthase.

Science.gov (United States)

Michel, J B; Feron, O; Sase, K; Prabhakar, P; Michel, T

1997-10-10

Nitric oxide is synthesized in diverse mammalian tissues by a family of calmodulin-dependent nitric oxide synthases. The endothelial isoform of nitric oxide synthase (eNOS) is targeted to the specialized signal-transducing membrane domains termed plasmalemmal caveolae. Caveolin, the principal structural protein in caveolae, interacts with eNOS and leads to enzyme inhibition in a reversible process modulated by Ca2+-calmodulin (Michel, J. B., Feron, O., Sacks, D., and Michel, T. (1997) J. Biol. Chem. 272, 15583-15586). Caveolin also interacts with other structurally distinct signaling proteins via a specific region identified within the caveolin sequence (amino acids 82-101) that appears to subserve the role of a "scaffolding domain." We now report that the co-immunoprecipitation of eNOS with caveolin is completely and specifically blocked by an oligopeptide corresponding to the caveolin scaffolding domain. Peptides corresponding to this domain markedly inhibit nitric oxide synthase activity in endothelial membranes and interact directly with the enzyme to inhibit activity of purified recombinant eNOS expressed in Escherichia coli. The inhibition of purified eNOS by the caveolin scaffolding domain peptide is competitive and completely reversed by Ca2+-calmodulin. These studies establish that caveolin, via its scaffolding domain, directly forms an inhibitory complex with eNOS and suggest that caveolin inhibits eNOS by abrogating the enzyme's activation by calmodulin.

Phytoplankton-bacterial interactions mediate micronutrient colimitation at the coastal Antarctic sea ice edge.

Science.gov (United States)

Bertrand, Erin M; McCrow, John P; Moustafa, Ahmed; Zheng, Hong; McQuaid, Jeffrey B; Delmont, Tom O; Post, Anton F; Sipler, Rachel E; Spackeen, Jenna L; Xu, Kai; Bronk, Deborah A; Hutchins, David A; Allen, Andrew E

2015-08-11

Southern Ocean primary productivity plays a key role in global ocean biogeochemistry and climate. At the Southern Ocean sea ice edge in coastal McMurdo Sound, we observed simultaneous cobalamin and iron limitation of surface water phytoplankton communities in late Austral summer. Cobalamin is produced only by bacteria and archaea, suggesting phytoplankton-bacterial interactions must play a role in this limitation. To characterize these interactions and investigate the molecular basis of multiple nutrient limitation, we examined transitions in global gene expression over short time scales, induced by shifts in micronutrient availability. Diatoms, the dominant primary producers, exhibited transcriptional patterns indicative of co-occurring iron and cobalamin deprivation. The major contributor to cobalamin biosynthesis gene expression was a gammaproteobacterial population, Oceanospirillaceae ASP10-02a. This group also contributed significantly to metagenomic cobalamin biosynthesis gene abundance throughout Southern Ocean surface waters. Oceanospirillaceae ASP10-02a displayed elevated expression of organic matter acquisition and cell surface attachment-related genes, consistent with a mutualistic relationship in which they are dependent on phytoplankton growth to fuel cobalamin production. Separate bacterial groups, including Methylophaga, appeared to rely on phytoplankton for carbon and energy sources, but displayed gene expression patterns consistent with iron and cobalamin deprivation. This suggests they also compete with phytoplankton and are important cobalamin consumers. Expression patterns of siderophore- related genes offer evidence for bacterial influences on iron availability as well. The nature and degree of this episodic colimitation appear to be mediated by a series of phytoplankton-bacterial interactions in both positive and negative feedback loops.

Prevention by Methionine of Enhancement of Hepatocarcinogenesis by Coadministration of a Choline‐deficient L‐Amino Acid‐defined Diet and Ethionine in Rats

Science.gov (United States)

Tsujiuchi, Toshifumi; Kobayashi, Eisaku; Nakae, Dai; Mizumoto, Yasushi; Andoh, Nobuaki; Kitada, Hiromichi; Ohashi, Kazuo; Fukuda, Tomokazu; Kido, Akira; Tsutsumi, Masahiro; Denda, Ayumi

1995-01-01

The effects of methionine on hepatocarcinogenesis induced by Coadministration of a choline‐deflcient L‐amino acid‐defined (CDAA) diet and ethionine were examined. F344 male rats were divided into 4 experimental groups. Groups 1 and 2 received the CDAA diet and a choline‐supplemented L‐amino acid‐defined (CSAA) diet, respectively. Group 3 received the CDAA diet containing 0.05% ethionine, and group 4 the CDAA diet containing 0.05% ethionine and 0.47% methionine. Animals were killed after 12 weeks of treatment. Histologically, the CDAA diet induced intracellular fat accumulation and foci. In contrast, ethionine caused not only foci, but also hyperplastic nodules, cholangiofibrosis and the proliferation of oval cells without such fat accumulation. Methionine abolished the development of all of the liver lesions induced by Coadministration of the CDAA diet and ethionine. To investigate the effects of methionine on induction of c‐myc and c‐Ha‐ras expression, as well as generation of 8‐hydroxyguanine (8‐OHGua) and 2‐thiobarbituric acid‐reacting substances (TBARS), by Coadministration of the CDAA diet and ethionine, subgroups of 3 to 5 animals were killed at 2, 4, 8 or 11 days after the beginning of the experiment. Coadministration of the CDAA diet and ethionine markedly enhanced the level of expression of c‐myc and c‐Ha‐ras, 8‐OHGua formation and TBARS generation as compared with the CDAA or CSAA diet within 11 days, and methionine blocked these actions. These results indicate that addition of methionine prevents the induction of c‐myc and c‐Ha‐ras expression, 8‐OHGua formation and TBARS generation, as well as hepatocellular lesions, by Coadministration of the CDAA diet and ethionine in rats, and suggest a possible involvement of oxidative stress and gene expression in hepatocarcinogenesis by these agents. PMID:8636001

Effects of methionine source, arginine: lysine ratio and sodium chloride level in the diets of grower broilers reared under high-temperature conditions

Directory of Open Access Journals (Sweden)

R Montanhini Neto

2013-06-01

Full Text Available The objective of this study was to evaluate the influence of methionine sources (DL-methionine 99% powder (DLM or methionine hydroxy analog liquid 88% (HMTBA, arginine:lysine (Arg:Lys ratio and sodium chloride (NaCl content in the diet of broilers on their performance, carcass yield, serum biochemistry, duodenal mucosal morphology, and immune response. Birds were kept under high temperature conditions during the grower phase and were inoculated or not with an antigen. The use of HMTBA promoted better live performance and carcass yield than the use of DLM. Diets with 1.05 Arg:Lys ratio resulted in better live performance, higher carcass and breast meat yields, longer villi, shallower crypts, and stronger immune response when broilers were challenged than the 1.40 ratio. The dietary supplementation of 6.0 g NaCl/kg promoted better growth performance and carcass weight than 2.0 g NaCl/kg. There was no influence of the different methionine sources or NaCl concentrations on any evaluated intestinal morphology parameter or immune response, nor of any interactions between these sources of variation.

Crystal structure of riboflavin synthase

Energy Technology Data Exchange (ETDEWEB)

Liao, D.-I.; Wawrzak, Z.; Calabrese, J.C.; Viitanen, P.V.; Jordan, D.B. (DuPont); (NWU)

2010-03-05

Riboflavin synthase catalyzes the dismutation of two molecules of 6,7-dimethyl-8-(1'-D-ribityl)-lumazine to yield riboflavin and 4-ribitylamino-5-amino-2,6-dihydroxypyrimidine. The homotrimer of 23 kDa subunits has no cofactor requirements for catalysis. The enzyme is nonexistent in humans and is an attractive target for antimicrobial agents of organisms whose pathogenicity depends on their ability to biosynthesize riboflavin. The first three-dimensional structure of the enzyme was determined at 2.0 {angstrom} resolution using the multiwavelength anomalous diffraction (MAD) method on the Escherichia coli protein containing selenomethionine residues. The homotrimer consists of an asymmetric assembly of monomers, each of which comprises two similar {beta} barrels and a C-terminal {alpha} helix. The similar {beta} barrels within the monomer confirm a prediction of pseudo two-fold symmetry that is inferred from the sequence similarity between the two halves of the protein. The {beta} barrels closely resemble folds found in phthalate dioxygenase reductase and other flavoproteins. The three active sites of the trimer are proposed to lie between pairs of monomers in which residues conserved among species reside, including two Asp-His-Ser triads and dyads of Cys-Ser and His-Thr. The proposed active sites are located where FMN (an analog of riboflavin) is modeled from an overlay of the {beta} barrels of phthalate dioxygenase reductase and riboflavin synthase. In the trimer, one active site is formed, and the other two active sites are wide open and exposed to solvent. The nature of the trimer configuration suggests that only one active site can be formed and be catalytically competent at a time.

The Tomato Terpene Synthase Gene Family1[W][OA

Science.gov (United States)

Falara, Vasiliki; Akhtar, Tariq A.; Nguyen, Thuong T.H.; Spyropoulou, Eleni A.; Bleeker, Petra M.; Schauvinhold, Ines; Matsuba, Yuki; Bonini, Megan E.; Schilmiller, Anthony L.; Last, Robert L.; Schuurink, Robert C.; Pichersky, Eran

2011-01-01

Compounds of the terpenoid class play numerous roles in the interactions of plants with their environment, such as attracting pollinators and defending the plant against pests. We show here that the genome of cultivated tomato (Solanum lycopersicum) contains 44 terpene synthase (TPS) genes, including 29 that are functional or potentially functional. Of these 29 TPS genes, 26 were expressed in at least some organs or tissues of the plant. The enzymatic functions of eight of the TPS proteins were previously reported, and here we report the specific in vitro catalytic activity of 10 additional tomato terpene synthases. Many of the tomato TPS genes are found in clusters, notably on chromosomes 1, 2, 6, 8, and 10. All TPS family clades previously identified in angiosperms are also present in tomato. The largest clade of functional TPS genes found in tomato, with 12 members, is the TPS-a clade, and it appears to encode only sesquiterpene synthases, one of which is localized to the mitochondria, while the rest are likely cytosolic. A few additional sesquiterpene synthases are encoded by TPS-b clade genes. Some of the tomato sesquiterpene synthases use z,z-farnesyl diphosphate in vitro as well, or more efficiently than, the e,e-farnesyl diphosphate substrate. Genes encoding monoterpene synthases are also prevalent, and they fall into three clades: TPS-b, TPS-g, and TPS-e/f. With the exception of two enzymes involved in the synthesis of ent-kaurene, the precursor of gibberellins, no other tomato TPS genes could be demonstrated to encode diterpene synthases so far. PMID:21813655

Isolation and functional effects of monoclonal antibodies binding to thymidylate synthase.

Science.gov (United States)

Jastreboff, M M; Todd, M B; Malech, H L; Bertino, J R

1985-01-29

Monoclonal antibodies against electrophoretically pure thymidylate synthase from HeLa cells have been produced. Antibodies (M-TS-4 and M-TS-9) from hybridoma clones were shown by enzyme-linked immunoassay to recognize thymidylate synthase from a variety of human cell lines, but they did not bind to thymidylate synthase from mouse cell lines. The strongest binding of antibodies was observed to enzyme from HeLa cells. These two monoclonal antibodies bind simultaneously to different antigenic sites on thymidylate synthase purified from HeLa cells, as reflected by a high additivity index and results of cross-linked radioimmunoassay. Both monoclonal antibodies inhibit the activity of thymidylate synthase from human cell lines. The strongest inhibition was observed with thymidylate synthase from HeLa cells. Monoclonal antibody M-TS-9 (IgM subclass) decreased the rate of binding of [3H]FdUMP to thymidylate synthase in the presence of 5,10-methylenetetrahydrofolate while M-TS-4 (IgG1) did not change the rate of ternary complex formation. These data indicate that the antibodies recognize different epitopes on the enzyme molecule.

Structure and mechanism of the diterpene cyclase ent-copalyl diphosphate synthase

Energy Technology Data Exchange (ETDEWEB)

Köksal, Mustafa; Hu, Huayou; Coates, Robert M.; Peters, Reuben J.; Christianson, David W. (UIUC); (Iowa State); (Penn)

2011-09-20

The structure of ent-copalyl diphosphate synthase reveals three {alpha}-helical domains ({alpha}, {beta} and {gamma}), as also observed in the related diterpene cyclase taxadiene synthase. However, active sites are located at the interface of the {beta}{gamma} domains in ent-copalyl diphosphate synthase but exclusively in the {alpha} domain of taxadiene synthase. Modular domain architecture in plant diterpene cyclases enables the evolution of alternative active sites and chemical strategies for catalyzing isoprenoid cyclization reactions.

Generation and Functional Evaluation of Designer Monoterpene Synthases.

Science.gov (United States)

Srividya, N; Lange, I; Lange, B M

2016-01-01

Monoterpene synthases are highly versatile enzymes that catalyze the first committed step in the pathways toward terpenoids, the structurally most diverse class of plant natural products. Recent advancements in our understanding of the reaction mechanism have enabled engineering approaches to develop mutant monoterpene synthases that produce specific monoterpenes. In this chapter, we are describing protocols to introduce targeted mutations, express mutant enzyme catalysts in heterologous hosts, and assess their catalytic properties. Mutant monoterpene synthases have the potential to contribute significantly to synthetic biology efforts aimed at producing larger amounts of commercially attractive monoterpenes. © 2016 Elsevier Inc. All rights reserved.

Evolutionary and mechanistic insights from the reconstruction of α-humulene synthases from a modern (+)-germacrene A synthase.

Science.gov (United States)

Gonzalez, Veronica; Touchet, Sabrina; Grundy, Daniel J; Faraldos, Juan A; Allemann, Rudolf K

2014-10-15

Germacrene A synthase (GAS) from Solidago canadensis catalyzes the conversion of farnesyl diphosphate (FDP) to the plant sesquiterpene (+)-germacrene A. After diphosphate expulsion, farnesyl cation reacts with the distal 10,11-double bond to afford germacrene A (>96%) and <2% α-humulene, which arises from 1,11-cyclization of FDP. The origin of the 1,11-activity of GAS was investigated by amino acid sequence alignments of 1,10- and 1,11-synthases and comparisons of X-ray crystal structures with the homology model of GAS; a triad [Thr 401-Gly 402-Gly 403] that might be responsible for the predominant 1,10-cyclization activity of GAS was identified. Replacement of Gly 402 with residues of increasing size led to a progressive increase of 1,11-cyclization. The catalytic robustness of these 1,10- /1,11-GAS variants point to Gly 402 as a functional switch of evolutionary significance and suggests that enzymes with strict functionalities have evolved from less specific ancestors through a small number of substitutions. Similar results were obtained with germacrene D synthase (GDS) upon replacement of the homologous active-site residue Gly 404: GDS-G404V generated approximately 20% bicyclogermacrene, a hydrocarbon with a cyclopropane ring that underlines the dual 1,10-/1,11-cyclization activity of this mutant. This suggests that the reaction pathways to germacrenes and humulenes might be connected through a bridged 1,10,11-carbocation intermediate or transition state that resembles bicyclogermacrene. Mechanistic studies using [1-(3)H1]-10-fluorofarnesyl diphosphate and deuterium-labeling experiments with [12,13-(2)H6]-FDP support a germacrene-humulene rearrangement linking 1,10- and 1,11-pathways. These results support the bioinformatics proposal that modern 1,10-synthases could have evolved from promiscuous 1,11-sesquiterpene synthases.

The crystal structure of human GDP-L-fucose synthase.

Science.gov (United States)

Zhou, Huan; Sun, Lihua; Li, Jian; Xu, Chunyan; Yu, Feng; Liu, Yahui; Ji, Chaoneng; He, Jianhua

2013-09-01

Human GDP-l-fucose synthase, also known as FX protein, synthesizes GDP-l-fucose from its substrate GDP-4-keto-6-deoxy-d-mannose. The reaction involves epimerization at both C-3 and C-5 followed by an NADPH-dependent reduction of the carbonyl at C-4. In this paper, the first crystal structure of human FX protein was determined at 2.37 Å resolution. The asymmetric unit of the crystal structure contains four molecules which form two homodimers. Each molecule consists of two domains, a Rossmann-fold NADPH-binding motif and a carboxyl terminal domain. Compared with the Escherichia coli GDP-l-fucose synthase, the overall structures of these two enzymes have four major differences. There are four loops in the structure of human FX protein corresponding to two α-helices and two β-sheets in that of the E. coli enzyme. Besides, there are seven different amino acid residues binding with NAPDH comparing human FX protein with that from E. coli. The structure of human FX reveals the key catalytic residues and could be useful for the design of drugs for the treatment of inflammation, auto-immune diseases, and possibly certain types of cancer.

Dietary folate, methionine, riboflavin, and vitamin B-6 and risk of sporadic colorectal cancer

NARCIS (Netherlands)

Vogel, S. de; Dindore, V.; Engeland, M. van; Goldbohm, R.A.; Brandt, P.A. van den; Weijenberg, M.P.

2008-01-01

Adequate intake of folate, methionine, riboflavin, and vitamin B-6 may prevent aberrant DNA methylation and thereby protect against colorectal cancer (CRC). However, previous epidemiological studies investigating associations between dietary intakes of these nutrients and CRC have been inconsistent.

The primary defect in glycogen synthase activity is not based on increased glycogen synthase kinase-3a activity in diabetic myotubes

DEFF Research Database (Denmark)

Gaster, Michael; Brusgaard, Klaus; Handberg, Aa.

2004-01-01

The mechanism responsible for the diminished activation of glycogen synthase (GS) in diabetic myotubes remains unclear, but may involve increased activity and/or expression of glycogen synthase kinase-3 (GSK-3). In myotubes established from type 2 diabetic and healthy control subjects we determined...

Insight into Biochemical Characterization of Plant Sesquiterpene Synthases

DEFF Research Database (Denmark)

Manczak, Tom; Simonsen, Henrik Toft

2016-01-01

A fast and reproducible protocol was established for enzymatic characterization of plant sesquiterpene synthases that can incorporate radioactivity in their products. The method utilizes the 96-well format in conjunction with cluster tubes and enables processing of >200 samples a day. Along...... with reduced reagent usage, it allows further reduction in the use of radioactive isotopes and flammable organic solvents. The sesquiterpene synthases previously characterized were expressed in yeast, and the plant-derived Thapsia garganica kunzeaol synthase TgTPS2 was tested in this method. KM for TgTPS2...... was found to be 0.55 μM; the turnover number, kcat, was found to be 0.29 s-1, kcat for TgTPS2 is in agreement with that of terpene synthases of other plants, and kcat/KM was found to be 0.53 s-1 μM-1 for TgTPS2. The kinetic parameters were in agreement with previously published data....

Engineering of methionine chain elongation part of glucoraphanin pathway in E. coli

DEFF Research Database (Denmark)

Mirza, Nadia Muhammad Akram; Crocoll, Christoph; Olsen, Carl Erik

2016-01-01

The methionine-derived glucosinolate glucoraphanin is associated with the health-promoting properties of broccoli. This has developed a strong interest in producing this compound in high amounts from a microbial source. Glucoraphanin synthesis starts with a five-gene chain elongation pathway...

Suites of terpene synthases explain differential terpenoid production in ginger and turmeric tissues.

Directory of Open Access Journals (Sweden)

Hyun Jo Koo

Full Text Available The essential oils of ginger (Zingiber officinale and turmeric (Curcuma longa contain a large variety of terpenoids, some of which possess anticancer, antiulcer, and antioxidant properties. Despite their importance, only four terpene synthases have been identified from the Zingiberaceae family: (+-germacrene D synthase and (S-β-bisabolene synthase from ginger rhizome, and α-humulene synthase and β-eudesmol synthase from shampoo ginger (Zingiber zerumbet rhizome. We report the identification of 25 mono- and 18 sesquiterpene synthases from ginger and turmeric, with 13 and 11, respectively, being functionally characterized. Novel terpene synthases, (--caryolan-1-ol synthase and α-zingiberene/β-sesquiphellandrene synthase, which is responsible for formation of the major sesquiterpenoids in ginger and turmeric rhizomes, were also discovered. These suites of enzymes are responsible for formation of the majority of the terpenoids present in these two plants. Structures of several were modeled, and a comparison of sets of paralogs suggests how the terpene synthases in ginger and turmeric evolved. The most abundant and most important sesquiterpenoids in turmeric rhizomes, (+-α-turmerone and (+-β-turmerone, are produced from (--α-zingiberene and (--β-sesquiphellandrene, respectively, via α-zingiberene/β-sesquiphellandrene oxidase and a still unidentified dehydrogenase.

Suites of Terpene Synthases Explain Differential Terpenoid Production in Ginger and Turmeric Tissues

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Koo, Hyun Jo; Gang, David R.

2012-01-01

The essential oils of ginger (Zingiber officinale) and turmeric (Curcuma longa) contain a large variety of terpenoids, some of which possess anticancer, antiulcer, and antioxidant properties. Despite their importance, only four terpene synthases have been identified from the Zingiberaceae family: (+)-germacrene D synthase and (S)-β-bisabolene synthase from ginger rhizome, and α-humulene synthase and β-eudesmol synthase from shampoo ginger (Zingiber zerumbet) rhizome. We report the identification of 25 mono- and 18 sesquiterpene synthases from ginger and turmeric, with 13 and 11, respectively, being functionally characterized. Novel terpene synthases, (−)-caryolan-1-ol synthase and α-zingiberene/β-sesquiphellandrene synthase, which is responsible for formation of the major sesquiterpenoids in ginger and turmeric rhizomes, were also discovered. These suites of enzymes are responsible for formation of the majority of the terpenoids present in these two plants. Structures of several were modeled, and a comparison of sets of paralogs suggests how the terpene synthases in ginger and turmeric evolved. The most abundant and most important sesquiterpenoids in turmeric rhizomes, (+)-α-turmerone and (+)-β-turmerone, are produced from (−)-α-zingiberene and (−)-β-sesquiphellandrene, respectively, via α-zingiberene/β-sesquiphellandrene oxidase and a still unidentified dehydrogenase. PMID:23272109

Partitioning of L-methionine in aqueous two-phase systems containing poly(propylene glycol) and sodium phosphate salts

International Nuclear Information System (INIS)

Salabat, Alireza; Sadeghi, Rahmat; Moghadam, Somayeh Tiani; Jamehbozorg, Bahman

2011-01-01

Highlights: → Thermodynamics parameters for partitioning of L-methionine in ATPS. → Investigation of different effects on partition coefficient of the amino acid. → Propose the best condition for L-methionine partitioning. - Abstract: The partitioning behavior of L-methionine has been studied in aqueous two-phase systems of (poly(propylene glycol) + sodium phosphate salts + H 2 O) at different temperatures. The salts used were sodium di-hydrogen phosphate (NaH 2 PO 4 ), di-sodium hydrogen phosphate (Na 2 HPO 4 ) and tri-sodium phosphate (Na 3 PO 4 ). The effects of tie line length, salt type, and temperature on the partition coefficient of this amino acid have been studied. In addition, thermodynamic parameters (ΔH o , ΔS o and ΔG o ) as a function of temperature were calculated. The results showed that increasing tie line length led to decreasing of the partition coefficient. We also showed that the partition coefficients of the amino acid in the systems containing Na 3 PO 4 are greater than the other two salts. Moreover, it is verified that increasing temperature led to decreasing the partition coefficient. The experimental partition coefficient data are correlated using a modified virial-type model.

Robot-performed synthesis of [11C]CH3-methionine with isolation by means of solid-phase extraction

International Nuclear Information System (INIS)

Vasil'ev, D.A.; Kiselev, M.Yu.; Korsakov, M.V.; Khorti, A.G.

1992-01-01

Robot-performed technology of synthesizing radiopharmaceutical preparation 11 CH 3 -methionine, used in positron-emission tomography of brain to evaluate the rate of protein biosynthesis was developed. The technology is based on the synthesis of 11 CH 3 -methionine from[ 11 C]-CH I and DL-homocysteinethiolactone with subsequent isolation of the preparation by the method of solid-phase extraction. Activity of the preparation synthesized is 0.13-0.17 Ci, specific activity -325-850 Ci/mmol, total duration of the synthesis from the moment of irradiation end is 16-19 min, radiochemical yield, as regards 11 CH 3 I corrected for carbon-11 decay, is 60 %

Variability of plasma and urine betaine in diabetes mellitus and its relationship to methionine load test responses: an observational study

OpenAIRE

Lever, Michael; Slow, Sandy; McGregor, David O; Dellow, Warwick J; George, Peter M; Chambers, Stephen T

2012-01-01

Abstract Background Since betaine is an osmolyte and methyl donor, and abnormal betaine loss is common in diabetes mellitus (>20% patients), we investigated the relationship between betaine and the post-methionine load rise in homocysteine, in diabetes and control subjects. The post-methionine load test is reported to be both an independent vascular risk factor and a measure of betaine sufficiency. Methods Patients with type 2 diabetes (n = 34) and control subjects (n = 17) were recruited. We...

CLONING, EXPRESSION, AND MUTATIONAL ANALYSIS OF RAT S-ADENOSYL-1-METHIONINE: ARSENIC (III) METHYLTRANSFERASE

Science.gov (United States)

CLONING, EXPRESSION, AND MUTATIONAL ANALYSIS OF RAT S-ADENOSYL-L-METHIONINE: ARSENIC(III) METHYLTRANSFERASEStephen B. Waters, Ph.D., Miroslav Styblo, Ph.D., Melinda A. Beck, Ph.D., University of North Carolina at Chapel Hill; David J. Thomas, Ph.D., U.S. Environmental...

Characterization of three chalcone synthase-like genes from apple (Malus x domestica Borkh.).

Science.gov (United States)

Yahyaa, Mosaab; Ali, Samah; Davidovich-Rikanati, Rachel; Ibdah, Muhammad; Shachtier, Alona; Eyal, Yoram; Lewinsohn, Efraim; Ibdah, Mwafaq

2017-08-01

Apple (Malus x domestica Brokh.) is a widely cultivated deciduous tree species of significant economic importance. Apple leaves accumulate high levels of flavonoids and dihydrochalcones, and their formation is dependent on enzymes of the chalcone synthase family. Three CHS genes were cloned from apple leaves and expressed in Escherichia coli. The encoded recombinant enzymes were purified and functionally characterized. In-vitro activity assays indicated that MdCHS1, MdCHS2 and MdCHS3 code for proteins exhibiting polyketide synthase activity that accepted either p-dihydrocoumaroyl-CoA, p-coumaroyl-CoA, or cinnamoyl-CoA as starter CoA substrates in the presence of malonyl-CoA, leading to production of phloretin, naringenin chalcone, and pinocembrin chalcone. MdCHS3 coded a chalcone-dihydrochalcone synthase enzyme with narrower substrate specificity than the previous ones. The apparent Km values of MdCHS3 for p-dihydrocoumaryl-CoA and p-coumaryl-CoA were both 5.0 μM. Expression analyses of MdCHS genes varied according to tissue type. MdCHS1, MdCHS2 and MdCHS3 expression levels were associated with the levels of phloretin accumulate in the respective tissues. Copyright © 2017 Elsevier Ltd. All rights reserved.

Crystallization and preliminary crystallographic analysis of mannosyl-3-phosphoglycerate synthase from Rubrobacter xylanophilus

International Nuclear Information System (INIS)

Sá-Moura, Bebiana; Albuquerque, Luciana; Empadinhas, Nuno; Costa, Milton S. da; Pereira, Pedro José Barbosa; Macedo-Ribeiro, Sandra

2008-01-01

The enzyme mannosyl-3-phosphoglycerate synthase from R. xylanophilus has been expressed, purified and crystallized. The crystals belong to the hexagonal space group P6 5 22 and diffract to 2.2 Å resolution. Rubrobacter xylanophilus is the only Gram-positive bacterium known to synthesize the compatible solute mannosylglycerate (MG), which is commonly found in hyperthermophilic archaea and some thermophilic bacteria. Unlike the salt-dependent pattern of accumulation observed in (hyper)thermophiles, in R. xylanophilus MG accumulates constitutively. The synthesis of MG in R. xylanophilus was tracked from GDP-mannose and 3-phosphoglycerate, but the genome sequence of the organism failed to reveal any of the genes known to be involved in this pathway. The native enzyme was purified and its N-terminal sequence was used to identify the corresponding gene (mpgS) in the genome of R. xylanophilus. The gene encodes a highly divergent mannosyl-3-phosphoglycerate synthase (MpgS) without relevant sequence homology to known mannosylphosphoglycerate synthases. In order to understand the specificity and enzymatic mechanism of this novel enzyme, it was expressed in Escherichia coli, purified and crystallized. The crystals thus obtained belonged to the hexagonal space group P6 5 22 and contained two protein molecules per asymmetric unit. The structure was solved by SIRAS using a mercury derivative

Associations between Intake of Folate, Methionine, and Vitamins B-12, B-6 and Prostate Cancer Risk in American Veterans

Directory of Open Access Journals (Sweden)

Adriana C. Vidal

2012-01-01

Full Text Available Prostate cancer (PC is the second leading cause of cancer death in men. Recent reports suggest that excess of nutrients involved in the one-carbon metabolism pathway increases PC risk; however, empirical data are lacking. Veteran American men (272 controls and 144 PC cases who attended the Durham Veteran American Medical Center between 2004–2009 were enrolled into a case-control study. Intake of folate, vitamin B12, B6, and methionine were measured using a food frequency questionnaire. Regression models were used to evaluate the association among one-carbon cycle nutrients, MTHFR genetic variants, and prostate cancer. Higher dietary methionine intake was associated with PC risk (OR = 2.1; 95%CI 1.1–3.9 The risk was most pronounced in men with Gleason sum <7 (OR = 2.75; 95%CI 1.32– 5.73. The association of higher methionine intake and PC risk was only apparent in men who carried at least one MTHFR A1298C allele (OR =6.7; 95%CI = 1.6–27.8, compared to MTHFR A1298A noncarrier men (OR =0.9; 95%CI = 0.24–3.92 (p-interaction =0.045. There was no evidence for associations between B vitamins (folate, B12, and B6 and PC risk. Our results suggest that carrying the MTHFR A1298C variants modifies the association between high methionine intake and PC risk. Larger studies are required to validate these findings.

Associations between Intake of Folate, Methionine, and Vitamins B-12, B-6 and Prostate Cancer Risk in American Veterans

International Nuclear Information System (INIS)

Vidal, A.C.; Hoyo, C.; Grant, D. J.

2012-01-01

Prostate cancer (PC) is the second leading cause of cancer death in men. Recent reports suggest that excess of nutrients involved in the one-carbon metabolism pathway increases PC risk; however, empirical data are lacking. Veteran American men (272 controls and 144 PC cases) who attended the Durham Veteran American Medical Center between 2004-2009 were enrolled into a case-control study. Intake of folate, vitamin B12, B6, and methionine were measured using a food frequency questionnaire. Regression models were used to evaluate the association among one-carbon cycle nutrients, MTHFR genetic variants, and prostate cancer. Higher dietary methionine intake was associated with PC risk (OR = 2.1; 95 % CI 1.1-3.9) The risk was most pronounced in men with Gleason sum <7 (OR = 2.75; 95%CI 1.32-5.73). The association of higher methionine intake and PC risk was only apparent in men who carried at least one MTHFR A1298C allele (OR=6.7 ; 95% CI=1.6-27.8), compared to MTHFR A1298A noncarrier men (OR = 0 . 9 ; 95 % CI=0.24-3.92) (p-interaction=0.045). There was no evidence for associations between B vitamins (folate, B12, and B6) and PC risk. Our results suggest that carrying the MTHFR A1298C variants modifies the association between high methionine intake and PC risk. Larger studies are required to validate these findings.

Cobalamin speciation using reversed-phase micro-high-performance liquid chromatography interfaced to inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Yanes, Enrique G.; Miller-Ihli, Nancy J.

2004-01-01

Micro-high-performance liquid chromatography interfaced to inductively coupled plasma mass spectrometry was optimized for the determination and separation of a mixture of cobalt containing species. Four cobalamin species (cyanocobalamin, hydroxocobalamin, methylcobalamin, and 5'-deoxyadenosylcobalamin) representing the various forms of vitamin B12 as well as the harmful corrinoid analogue cobinamide dicyanide were separated using reversed-phase microcapillary chromatography with columns containing C18 packing material with a 2-μm particle size. Selection of organic solvents for the separation took into consideration compatibility with the inductively coupled plasma mass spectrometer being used for element specific detection. Optimized method conditions included use of a methanol gradient and make-up solution for the nebulizer. Some issues associated with dead volume were overcome by the extension of the gradient program. The total analysis time was 52 min. The column-to-column variability was evaluated and was found to be very reasonable (9% RSD on average), confirming that this method is rugged and that the technology should be easily transferred to other laboratories

Structure of the ent -Copalyl Diphosphate Synthase PtmT2 from Streptomyces platensis CB00739, a Bacterial Type II Diterpene Synthase

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Rudolf, Jeffrey D.; Dong, Liao-Bin; Cao, Hongnan; Hatzos-Skintges, Catherine; Osipiuk, Jerzy; Endres, Michael; Chang, Chin-Yuan; Ma, Ming; Babnigg, Gyorgy; Joachimiak, Andrzej; Phillips, George N.; Shen, Ben

2016-08-31

Terpenoids are the largest and most structurally diverse family of natural products found in nature, yet their presence in bacteria is underappreciated. The carbon skeletons of terpenoids are generated through carbocation-dependent cyclization cascades catalyzed by terpene synthases (TSs). Type I and type II TSs initiate cyclization via diphosphate ionization and protonation, respectively, and protein structures of both types are known. Most plant diterpene synthases (DTSs) possess three alpha-helical domains (alpha beta gamma), which are thought to have arisen from the fusion of discrete, ancestral bacterial type I TSs (alpha) and type II TSs (beta gamma). Type II DTSs of bacterial origin, of which there are no structurally characterized members, are a missing piece in the structural evolution of TSs. Here, we report the first crystal structure of a type II DTS from bacteria. PtnaT2 from Streptomyces platensis CB00739 was verified as an ent-copalyl diphosphate synthase involved in the biosynthesis of platensimycin and platencin. The crystal structure of PtmT2 was solved at a resolution of 1.80 angstrom, and docking studies suggest the catalytically active conformation of geranylgeranyl diphosphate (GGPP). Site-directed mutagenesis confirmed residues involved in binding the diphosphate moiety of GGPP and identified DxxxxE as a potential Mg2+-binding motif for type II DTSs of bacterial origin. Finally, both the shape and physicochemical properties of the active sites are responsible for determining specific catalytic outcomes of TSs. The structure of PtmT2 fundamentally advances the knowledge of bacterial TSs, their mechanisms, and their role in the evolution of TSs.

l-Methionine and silymarin: A comparison of prophylactic protective capabilities in acetaminophen-induced injuries of the liver, kidney and cerebral cortex.

Science.gov (United States)

Onaolapo, Olakunle J; Adekola, Moses A; Azeez, Taiwo O; Salami, Karimat; Onaolapo, Adejoke Y

2017-01-01

We compared the relative protective abilities of silymarin and l-methionine pre-treatment in acetaminophen overdose injuries of the liver, kidney and cerebral cortex by assessing behaviours, antioxidant status, tissue histological changes and biochemical parameters of hepatic/renal function. Rats were divided into six groups of ten each; animals in five of these groups were pre-treated with oral distilled water, silymarin (25mg/kg) or l-methionine (2.5, 5 and 10mg/kg body weight) for 14days; and then administered intraperitoneal (i.p.) acetaminophen at 800mg/kg/day for 3days. Rats in the sixth group (normal control) received distilled water orally for 14days and then i.p. for 3days. Neurobehavioural tests were conducted 7days after last i.p treatment, and animals sacrificed on the 8th day. Plasma was assayed for biochemical markers of liver/kidney function; while sections of the liver, kidney and cerebral cortex were either homogenised for assay of antioxidant status or processed for histology. Acetaminophen overdose resulted in locomotor retardation, excessive self-grooming, working-memory impairment, anxiety, derangement of liver/kidney biochemistry, antioxidant imbalance, and histological changes in the liver, kidney and cerebral cortex. Administration of silymarin or increasing doses of l-methionine counteracted the behavioural changes, reversed biochemical indices of liver/kidney injury, and improved antioxidant activity. Silymarin and l-methionine also conferred variable degrees of tissue protection, on histology. Either silymarin or l-methionine can protect vulnerable tissues from acetaminophen overdose injury; however, each offers variable protection to different tissues. This study highlights an obstacle to seeking the 'ideal' protective agent against acetaminophen overdose. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Kinetic Modeling of Methionine Oxidation in Monoclonal Antibodies from Hydrogen Peroxide Spiking Studies.

Science.gov (United States)

Hui, Ada; Lam, Xanthe M; Kuehl, Christopher; Grauschopf, Ulla; Wang, Y John

2015-01-01

When isolator technology is applied to biotechnology drug product fill-finish process, hydrogen peroxide (H2O2) spiking studies for the determination of the sensitivity of protein to residual peroxide in the isolator can be useful for assessing a maximum vapor phase hydrogen peroxide (VPHP) level. When monoclonal antibody (mAb) drug products were spiked with H2O2, an increase in methionine (Met 252 and Met 428) oxidation in the Fc region of the mAbs with a decrease in H2O2 concentration was observed for various levels of spiked-in peroxide. The reaction between Fc-Met and H2O2 was stoichiometric (i.e., 1:1 molar ratio), and the reaction rate was dependent on the concentrations of mAb and H2O2. The consumption of H2O2 by Fc-Met oxidation in the mAb followed pseudo first-order kinetics, and the rate was proportional to mAb concentration. The extent of Met 428 oxidation was half of that of Met 252, supporting that Met 252 is twice as reactive as Met 428. Similar results were observed for free L-methionine when spiked with H2O2. However, mAb formulation excipients may affect the rate of H2O2 consumption. mAb formulations containing trehalose or sucrose had faster H2O2 consumption rates than formulations without the sugars, which could be the result of impurities (e.g., metal ions) present in the excipients that may act as catalysts. Based on the H2O2 spiking study results, we can predict the amount Fc-Met oxidation for a given protein concentration and H2O2 level. Our kinetic modeling of the reaction between Fc-Met oxidation and H2O2 provides an outline to design a H2O2 spiking study to support the use of VPHP isolator for antibody drug product manufacture. Isolator technology is increasing used in drug product manufacturing of biotherapeutics. In order to understand the impact of residual vapor phase hydrogen peroxide (VPHP) levels on protein product quality, hydrogen peroxide (H2O2) spiking studies may be performed to determine the sensitivity of monoclonal antibody

Effect of different levels of lysine in the diet of broilers on the metabolism of /sup 35/S-methionine

Energy Technology Data Exchange (ETDEWEB)

Stanchev, Kh; Venkov, T; Dzharova, M [Akademiya na Selskostopanskite Nauki, Sofia-Kostinbrod (Bulgaria). Inst. po Zhivotnovydstvo

1974-01-01

The lack of balance of the ration with respect to lysine leads to a decrease in the rate of incorporation of /sup 35/S-methionine in the liver, pancreas, kidney and femoral muscle. Most intensive protein synthesis in the liver of chickens is observed in the group receiving ration balanced with respect to lysine while in the case of a deficiency or excess of lysine the protein biosynthesis drops. The deficiency or excess of lysine leads to an increase in the excretion rate and decreases the assimilability of radioactive methionine in the chickens organisms. (INIS)

Highly divergent mitochondrial ATP synthase complexes in Tetrahymena thermophila.

Directory of Open Access Journals (Sweden)

Praveen Balabaskaran Nina

2010-07-01

Full Text Available The F-type ATP synthase complex is a rotary nano-motor driven by proton motive force to synthesize ATP. Its F(1 sector catalyzes ATP synthesis, whereas the F(o sector conducts the protons and provides a stator for the rotary action of the complex. Components of both F(1 and F(o sectors are highly conserved across prokaryotes and eukaryotes. Therefore, it was a surprise that genes encoding the a and b subunits as well as other components of the F(o sector were undetectable in the sequenced genomes of a variety of apicomplexan parasites. While the parasitic existence of these organisms could explain the apparent incomplete nature of ATP synthase in Apicomplexa, genes for these essential components were absent even in Tetrahymena thermophila, a free-living ciliate belonging to a sister clade of Apicomplexa, which demonstrates robust oxidative phosphorylation. This observation raises the possibility that the entire clade of Alveolata may have invented novel means to operate ATP synthase complexes. To assess this remarkable possibility, we have carried out an investigation of the ATP synthase from T. thermophila. Blue native polyacrylamide gel electrophoresis (BN-PAGE revealed the ATP synthase to be present as a large complex. Structural study based on single particle electron microscopy analysis suggested the complex to be a dimer with several unique structures including an unusually large domain on the intermembrane side of the ATP synthase and novel domains flanking the c subunit rings. The two monomers were in a parallel configuration rather than the angled configuration previously observed in other organisms. Proteomic analyses of well-resolved ATP synthase complexes from 2-D BN/BN-PAGE identified orthologs of seven canonical ATP synthase subunits, and at least 13 novel proteins that constitute subunits apparently limited to the ciliate lineage. A mitochondrially encoded protein, Ymf66, with predicted eight transmembrane domains could be a

Molecular cloning and functional expression of geranylgeranyl pyrophosphate synthase from Coleus forskohlii Briq

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Kawamukai Makoto

2004-11-01

Full Text Available Abstract Background Isopentenyl diphosphate (IPP, a common biosynthetic precursor to the labdane diterpene forskolin, has been biosynthesised via a non-mevalonate pathway. Geranylgeranyl diphosphate (GGPP synthase is an important branch point enzyme in terpenoid biosynthesis. Therefore, GGPP synthase is thought to be a key enzyme in biosynthesis of forskolin. Herein we report the first confirmation of the GGPP synthase gene in Coleus forskohlii Briq. Results The open reading frame for full-length GGPP synthase encodes a protein of 359 amino acids, in which 1,077 nucleotides long with calculated molecular mass of 39.3 kDa. Alignments of C. forskohlii GGPP synthase amino acid sequences revealed high homologies with other plant GGPP synthases. Several highly conserved regions, including two aspartate-rich motifs were identified. Transient expression of the N-terminal region of C. forskohlii GGPP synthase-GFP fusion protein in tobacco cells demonstrated subcellular localization in the chloroplast. Carotenoid production was observed in Escherichia coli harboring pACCAR25ΔcrtE from Erwinia uredovora and plasmid carrying C. forskohlii GGPP synthase. These results suggested that cDNA encoded functional GGPP synthase. Furthermore, C. forskohlii GGPP synthase expression was strong in leaves, decreased in stems and very little expression was observed in roots. Conclusion This investigation proposed that forskolin was synthesised via a non-mevalonate pathway. GGPP synthase is thought to be involved in the biosynthesis of forskolin, which is primarily synthesised in the leaves and subsequently accumulates in the stems and roots.

Convergent signaling pathways – interaction between methionine oxidation and serine/threonine/tyrosine O-phosphorylation

Science.gov (United States)

Oxidation of Methionine (Met) to Met sulfoxide (MetSO) is a frequently found reversible post-translational modification. It has been presumed that the major functional role for oxidation-labile Met residues is to protect proteins/cells from oxidative stress. However, Met oxidation has been establi...

Vibrational and thermal study of l-methionine nitrate polycrystals

Energy Technology Data Exchange (ETDEWEB)

Victor, F.M.S.; Ribeiro, L.H.L.; Facanha Filho, P.F.; Santos, C.A.S.; Soares, R.A.; Abreu, D.C.; Sousa, J.C.F.; Carvalho, J.O.; Santos, A.O. dos [Universidade Federal do Maranhao (UFMA), MA (Brazil)

2016-07-01

Full text: Intensified in studies of nonlinear optical materials has been observed over the past two decades for its wide application in telecommunications, optical modulation and optical signal processing. The goal of this work is the thermal and vibrational study of L-methionine nitrate polycrystalline. The polycrystals were obtained by the method of slow evaporation of solvent at ambient temperature of 25 ° C. The X-ray diffraction was performed to confirm the structure of the material, which has monoclinic structure (space group P21) with four molecules per unit cell structure. Refinement by Rietveld method has been optimized and good quality parameters Rwp = 7.97% , Rp = 5.74 and S = 1.92%. The thermal stability of the material was verified from Thermogravimetric analysis (TGA), Differential Thermal Analysis (DTA) and Differential Scanning Calorimetry (DSC). The measures showed a possible phase transition event at about 107°C before the melting point of the material, which took place at about 127°C. Thermogravimetric analysis showed two mass loss events of 61.5% and 30.4%. The vibrational modes of the L-methionine nitrate molecule were identified by Raman spectroscopy in the spectral range between 35cm-1 and 3500 cm-1, the scattering measurements were made from room temperature up to the melting temperature of the material (140 ° C ) in which the disappearance of bands was found in the region of normal modes at 130 ° C, thus demonstrating a irreversible structural phase transition, because the spectrum obtained after returning the sample to ambient temperature is typical of amorphous material. (author)

Effect of two different sublingual dosages of vitamin B12 on cobalamin nutritional status in vegans and vegetarians with a marginal deficiency: A randomized controlled trial.

Science.gov (United States)

Del Bo', Cristian; Riso, Patrizia; Gardana, Claudio; Brusamolino, Antonella; Battezzati, Alberto; Ciappellano, Salvatore

2018-02-15

Vegetarians and vegans are more vulnerable to vitamin B 12 deficiency with severe risks of megaloblastic anemia, cognitive decline, neuropathy, and depression. An easy and simple method of supplementation consists of taking one weekly dosage of 2000 μg. However, single large oral doses of vitamin B 12 are poorly absorbed. The present research evaluates the ability of two different sublingual dosages of vitamin B 12 (350 μg/week vs 2000 μg/week) in improving cyanocobalamin (vitamin B 12 ) nutritional status in vegans and vegetarians with a marginal deficiency. A 12-week randomized, double-blind, controlled, parallel intervention trial was performed. Forty subjects with marginal vitamin B 12 deficiency were enrolled and randomly divided into two groups: test group Ld (low dose, 350 μg/week) and control group Hd (high dose, 2000 μg/week) vitamin B 12 supplementation. Blood samples were collected at baseline and after 15, 30, 60, and 90 days from the intervention for the determination of vitamin B 12 , related metabolic markers, and blood cell counts. Two-way analysis of variance showed a significant effect of time (P < 0.0001) and of time × treatment interaction (P = 0.012) on serum concentration of vitamin B 12 that increased after 90-day supplementation (Ld and Hd) compared to baseline. Both the supplements increased (P < 0.0001, time effect) the levels of holotranscobalamin, succinic acid, methionine and wellness parameter, while decreased (P < 0.0001, time effect) the levels of methylmalonic acid, homocysteine and folate compared to baseline. No difference was observed between groups (LdvsHd). No effect was detected for vitamin B 6 and blood cell count. In our experimental conditions, both supplements were able to restore adequate serum concentrations of vitamin B 12 and to improve the levels of related metabolic blood markers in subjects with a marginal deficiency. The results support the use of a sublingual dosage of 50 μg/day (350�

Bacillus caldolyticus prs gene encoding phosphoribosyldiphosphate synthase

DEFF Research Database (Denmark)

Krath, Britta N.; Hove-Jensen, Bjarne

1996-01-01

The prs gene, encoding phosphoribosyl-diphosphate (PRPP) synthase, as well as the flanking DNA sequences were cloned and sequenced from the Gram-positive thermophile, Bacillus caldolyticus. Comparison with the homologous sequences from the mesophile, Bacillus subtilis, revealed a gene (gca......D) encoding N-acetylglucosamine-l-phosphate uridyltransferase upstream of prs, and a gene homologous to ctc downstream of prs. cDNA synthesis with a B. caldolyticus gcaD-prs-ctc-specified mRNA as template, followed by amplification utilising the polymerase chain reaction indicated that the three genes are co......-transcribed. Comparison of amino acid sequences revealed a high similarity among PRPP synthases across a wide phylogenetic range. An E. coli strain harbouring the B. caldolyticus prs gene in a multicopy plasmid produced PRPP synthase activity 33-fold over the activity of a haploid B. caldolyticus strain. B. caldolyticus...

Post-irradiation inactivation, protection, and repair of the sulfhydryl enzyme malate synthase

International Nuclear Information System (INIS)

Durchschlag, H.; Zipper, P.

1985-01-01

Malate synthase from baker's yeast, a trimeric sulfhydryl enzyme with one essential sulfhydryl group per subunit, was inactivated by 2 kGy X-irradiation in air-saturated aqueous solution (enzyme concentration: 0.5 mg/ml). The radiation induced changes of enzymic activity were registered at about 0,30,60 h after irradiation. To elucidate the role of OH - , O 2 , and H 2 O 2 in the X-ray inactivation of the enzyme, experiments were performed in the absence of presence of different concentrations of specific additives (formate, superoxide dismutase, catalase). These additives were added to malate synthase solutions before or after X-irradiation. Moreover, repairs of inactivated malate synthase were initiated at about 0 or 30 h after irradiation by means of the sulfhydryl agent dithiothreitol. Experiments yielded the following results: 1. Irradiation of malate synthase in the absence of additives inactivated the enzyme immediately to a residual activity Asub(r)=3% (corresponding to a D 37 =0.6 kGy), and led to further slow inactivation in the post-irradiation phase. Repairs, initiated at different times after irradiation, restored enzymic activity considerably. The repair initiated at t=0 led to Asub(r)=21%; repairs started later on resulted in somewhat lower activities. The decay of reparability, however, was found to progress more slowly than post-irradiation inactivation itself. After completion of repair the activities of repaired samples did not decrease significantly. 2. The presence of specific additives during irradiation caused significant protective effects against primary inactivation. The protection by formate was very pronounced (e.g., Asub(r)=72% and D 37 =6 kGy for 100 mM formate). The presence of catalytic amounts of superoxide dismutase and/or catalase exhibited only minor effects, depending on the presence and concentration of formate. (orig.)

Effects of hypercapnia and NO synthase inhibition in sustained hypoxic pulmonary vasoconstriction

Science.gov (United States)

2012-01-01

Background Acute respiratory disorders may lead to sustained alveolar hypoxia with hypercapnia resulting in impaired pulmonary gas exchange. Hypoxic pulmonary vasoconstriction (HPV) optimizes gas exchange during local acute (0-30 min), as well as sustained (> 30 min) hypoxia by matching blood perfusion to alveolar ventilation. Hypercapnia with acidosis improves pulmonary gas exchange in repetitive conditions of acute hypoxia by potentiating HPV and preventing pulmonary endothelial dysfunction. This study investigated, if the beneficial effects of hypercapnia with acidosis are preserved during sustained hypoxia as it occurs, e.g in permissive hypercapnic ventilation in intensive care units. Furthermore, the effects of NO synthase inhibitors under such conditions were examined. Method We employed isolated perfused and ventilated rabbit lungs to determine the influence of hypercapnia with or without acidosis (pH corrected with sodium bicarbonate), and inhibitors of endothelial as well as inducible NO synthase on acute or sustained HPV (180 min) and endothelial permeability. Results In hypercapnic acidosis, HPV was intensified in sustained hypoxia, in contrast to hypercapnia without acidosis when HPV was amplified during both phases. L-NG-Nitroarginine (L-NNA), a non-selective NO synthase inhibitor, enhanced acute as well as sustained HPV under all conditions, however, the amplification of sustained HPV induced by hypercapnia with or without acidosis compared to normocapnia disappeared. In contrast 1400 W, a selective inhibitor of inducible NO synthase (iNOS), decreased HPV in normocapnia and hypercapnia without acidosis at late time points of sustained HPV and selectively reversed the amplification of sustained HPV during hypercapnia without acidosis. Hypoxic hypercapnia without acidosis increased capillary filtration coefficient (Kfc). This increase disappeared after administration of 1400 W. Conclusion Hypercapnia with and without acidosis increased HPV during

Effects of hypercapnia and NO synthase inhibition in sustained hypoxic pulmonary vasoconstriction

Directory of Open Access Journals (Sweden)

Ketabchi Farzaneh

2012-01-01

Full Text Available Abstract Background Acute respiratory disorders may lead to sustained alveolar hypoxia with hypercapnia resulting in impaired pulmonary gas exchange. Hypoxic pulmonary vasoconstriction (HPV optimizes gas exchange during local acute (0-30 min, as well as sustained (> 30 min hypoxia by matching blood perfusion to alveolar ventilation. Hypercapnia with acidosis improves pulmonary gas exchange in repetitive conditions of acute hypoxia by potentiating HPV and preventing pulmonary endothelial dysfunction. This study investigated, if the beneficial effects of hypercapnia with acidosis are preserved during sustained hypoxia as it occurs, e.g in permissive hypercapnic ventilation in intensive care units. Furthermore, the effects of NO synthase inhibitors under such conditions were examined. Method We employed isolated perfused and ventilated rabbit lungs to determine the influence of hypercapnia with or without acidosis (pH corrected with sodium bicarbonate, and inhibitors of endothelial as well as inducible NO synthase on acute or sustained HPV (180 min and endothelial permeability. Results In hypercapnic acidosis, HPV was intensified in sustained hypoxia, in contrast to hypercapnia without acidosis when HPV was amplified during both phases. L-NG-Nitroarginine (L-NNA, a non-selective NO synthase inhibitor, enhanced acute as well as sustained HPV under all conditions, however, the amplification of sustained HPV induced by hypercapnia with or without acidosis compared to normocapnia disappeared. In contrast 1400 W, a selective inhibitor of inducible NO synthase (iNOS, decreased HPV in normocapnia and hypercapnia without acidosis at late time points of sustained HPV and selectively reversed the amplification of sustained HPV during hypercapnia without acidosis. Hypoxic hypercapnia without acidosis increased capillary filtration coefficient (Kfc. This increase disappeared after administration of 1400 W. Conclusion Hypercapnia with and without acidosis

Effects of hypercapnia and NO synthase inhibition in sustained hypoxic pulmonary vasoconstriction.

Science.gov (United States)

Ketabchi, Farzaneh; Ghofrani, Hossein A; Schermuly, Ralph T; Seeger, Werner; Grimminger, Friedrich; Egemnazarov, Bakytbek; Shid-Moosavi, S Mostafa; Dehghani, Gholam A; Weissmann, Norbert; Sommer, Natascha

2012-01-31

Acute respiratory disorders may lead to sustained alveolar hypoxia with hypercapnia resulting in impaired pulmonary gas exchange. Hypoxic pulmonary vasoconstriction (HPV) optimizes gas exchange during local acute (0-30 min), as well as sustained (> 30 min) hypoxia by matching blood perfusion to alveolar ventilation. Hypercapnia with acidosis improves pulmonary gas exchange in repetitive conditions of acute hypoxia by potentiating HPV and preventing pulmonary endothelial dysfunction. This study investigated, if the beneficial effects of hypercapnia with acidosis are preserved during sustained hypoxia as it occurs, e.g in permissive hypercapnic ventilation in intensive care units. Furthermore, the effects of NO synthase inhibitors under such conditions were examined. We employed isolated perfused and ventilated rabbit lungs to determine the influence of hypercapnia with or without acidosis (pH corrected with sodium bicarbonate), and inhibitors of endothelial as well as inducible NO synthase on acute or sustained HPV (180 min) and endothelial permeability. In hypercapnic acidosis, HPV was intensified in sustained hypoxia, in contrast to hypercapnia without acidosis when HPV was amplified during both phases. L-NG-Nitroarginine (L-NNA), a non-selective NO synthase inhibitor, enhanced acute as well as sustained HPV under all conditions, however, the amplification of sustained HPV induced by hypercapnia with or without acidosis compared to normocapnia disappeared. In contrast 1400 W, a selective inhibitor of inducible NO synthase (iNOS), decreased HPV in normocapnia and hypercapnia without acidosis at late time points of sustained HPV and selectively reversed the amplification of sustained HPV during hypercapnia without acidosis. Hypoxic hypercapnia without acidosis increased capillary filtration coefficient (Kfc). This increase disappeared after administration of 1400 W. Hypercapnia with and without acidosis increased HPV during conditions of sustained hypoxia. The

Beta-Glucan Synthase Gene Expression in Pleurotus sp

International Nuclear Information System (INIS)

Azhar Mohamad; Nie, H.J.

2016-01-01

Pleurotus sp. is a popular edible mushroom, containing various functional component, in particular, Beta-glucan. Beta-glucans is a part of glucan family of polysaccharides and supposedly contribute to medicinal and nutritional value of Pleurotus.sp. In order to understand the distribution of Beta-glucan in Pleurotus.sp, the Beta-glucan synthase gene expression was determined and compared in different part of Pleurotus, namely mycelium, stripe and cap. The Pleurotus.sp RNA was extracted using commercial kit, employing Tissuelyser ll (Qiagen, USA) to disrupt the cell walls. Then the RNA was quantified by Nano drop (Thermo Fisher, USA) and visualized using denaturing agarose gel. RNA with good OD 260.280 reading (∼2.0) was chosen and converted to cDNA. Using Laccase synthase gene as home keeping gene, Beta-glucan synthase gene expression was quantified using CFX 96 Real Time PCR detection system (Biorad, USA). Preliminary result shows that Beta-glucan synthase was relatively expressed the most in stripe, followed by mycelium and barely in cap. (author)

Synthesis, characterization of Ag-Au core-shell bimetal nanoparticles and its application for electrocatalytic oxidation/sensing of L-methionine

Energy Technology Data Exchange (ETDEWEB)

Murugavelu, M.; Karthikeyan, B., E-mail: bkarthi_au@yahoo.com

2017-01-01

The Ag-Au core-shell bimetal nanoparticles (BNPs) was prepared using chemical reduction method. The prepared Ag-Au core-shell BNPs were characterized by UV–Visible (UV–Vis) spectroscopy, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) pattern. These results showed the Ag-Au BNPs exhibited core-shell shape. The Ag-Au core-shell BNPs was examined towards electrocatalytic oxidation of L-methionine (L-Met) by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperometry. According to the results, L-Met is determined with detection limit of 30 μM. Interference studies in biological buffer was also studied. - Highlights: • The Ag-Au core-shell BNPs are synthesized and characterized • Ag-Au core-shell BNPs modified (Ag-Au/GCE) has been examined for L-methionine oxidation/sensing by using electrochemical method. • The Ag-Au/GCE exhibited good performance for the detection of L-methionine.

Regulation of longevity and oxidative stress by nutritional interventions: role of methionine restriction.

Science.gov (United States)

Sanchez-Roman, Ines; Barja, Gustavo

2013-10-01

Comparative studies indicate that long-lived mammals have low rates of mitochondrial reactive oxygen species production (mtROSp) and oxidative damage in their mitochondrial DNA (mtDNA). Dietary restriction (DR), around 40%, extends the mean and maximum life span of a wide range of species and lowers mtROSp and oxidative damage to mtDNA, which supports the mitochondrial free radical theory of aging (MFRTA). Regarding the dietary factor responsible for the life extension effect of DR, neither carbohydrate nor lipid restriction seems to modify maximum longevity. However protein restriction (PR) and methionine restriction (at least 80% MetR) increase maximum lifespan in rats and mice. Interestingly, only 7weeks of 40% PR (at least in liver) or 40% MetR (in all the studied organs, heart, brain, liver or kidney) is enough to decrease mtROSp and oxidative damage to mtDNA in rats, whereas neither carbohydrate nor lipid restriction changes these parameters. In addition, old rats also conserve the capacity to respond to 7weeks of 40% MetR with these beneficial changes. Most importantly, 40% MetR, differing from what happens during both 40% DR and 80% MetR, does not decrease growth rate and body size of rats. All the available studies suggest that the decrease in methionine ingestion that occurs during DR is responsible for part of the aging-delaying effect of this intervention likely through the decrease of mtROSp and ensuing DNA damage that it exerts. We conclude that lowering mtROS generation is a conserved mechanism, shared by long-lived species and dietary, protein, and methionine restricted animals, that decreases damage to macromolecules situated near the complex I mtROS generator, especially mtDNA. This would decrease the accumulation rate of somatic mutations in mtDNA and maybe finally also in nuclear DNA. Copyright © 2013 Elsevier Inc. All rights reserved.

Sequence analysis of cereal sucrose synthase genes and isolation ...

African Journals Online (AJOL)

SERVER

2007-10-18

Oct 18, 2007 ... sequencing of sucrose synthase gene fragment from sor- ghum using primers designed at their conserved exons. MATERIALS AND METHODS. Multiple sequence alignment. Sucrose synthase gene sequences of various cereals like rice, maize, and barley were accessed from NCBI Genbank database.

Homology modeling of Homo sapiens lipoic acid synthase: Substrate docking and insights on its binding mode.

Science.gov (United States)

Krishnamoorthy, Ezhilarasi; Hassan, Sameer; Hanna, Luke Elizabeth; Padmalayam, Indira; Rajaram, Rama; Viswanathan, Vijay

2017-05-07

Lipoic acid synthase (LIAS) is an iron-sulfur cluster mitochondrial enzyme which catalyzes the final step in the de novo pathway for the biosynthesis of lipoic acid, a potent antioxidant. Recently there has been significant interest in its role in metabolic diseases and its deficiency in LIAS expression has been linked to conditions such as diabetes, atherosclerosis and neonatal-onset epilepsy, suggesting a strong inverse correlation between LIAS reduction and disease status. In this study we use a bioinformatics approach to predict its structure, which would be helpful to understanding its role. A homology model for LIAS protein was generated using X-ray crystallographic structure of Thermosynechococcus elongatus BP-1 (PDB ID: 4U0P). The predicted structure has 93% of the residues in the most favour region of Ramachandran plot. The active site of LIAS protein was mapped and docked with S-Adenosyl Methionine (SAM) using GOLD software. The LIAS-SAM complex was further refined using molecular dynamics simulation within the subsite 1 and subsite 3 of the active site. To the best of our knowledge, this is the first study to report a reliable homology model of LIAS protein. This study will facilitate a better understanding mode of action of the enzyme-substrate complex for future studies in designing drugs that can target LIAS protein. Copyright © 2017 Elsevier Ltd. All rights reserved.

Studies on N5-methyltetrahydrofolate-homocystein methyltransferase in normal and leukemia leukocytes.

Science.gov (United States)

Peytremann, R; Thorndike, J; Beck, W S

1975-11-01

A cobalamin-dependent N5-methyltetra-hydrofolate-homocysteine methyltransferase (methyl-transferase) was demonstrated in unfractioned extracts of human normal and leukemia leukocytes. Activity was substantially reduced in the absence of an added cobalamin derivative. Presumably, this residual activity reflects the endogeneous level of holoenzyme. Enzyme activity was notably higher in lymphoid cells than in myeloid cells. Thus, mean specific activities (+/-SD) were: chronic lymphocytic leukemia lymphocytes, 2.15+/-1.16; normal lymphocytes, 0.91+/-0.59; normal mature granulocytes, 0.15+/-0.10; chronic myelocytic leukemia granulocytes, barely detectable activity. Properties of leukocytes enzymes resembled those of methyltransferases previously studied in bacteria and other animal cells. Granulocytes and chronic myelocytic leukemia cells contain a factor or factors that inhibits Escherichia coli enzyme. The data suggest that the prominence of this cobalamin-dependent enzyme in lymphocytes and other mononuclear cell types may be related to their potential for cell division.

Partitioning of L-methionine in aqueous two-phase systems containing poly(propylene glycol) and sodium phosphate salts

Energy Technology Data Exchange (ETDEWEB)

Salabat, Alireza, E-mail: a-salabat@araku.ac.ir [Chemistry Department, Arak University, P.O. Box 38156-879, Arak (Iran, Islamic Republic of); Sadeghi, Rahmat [Department of Chemistry, University of Kurdistan, Sanandaj, Kurdistan 66135 (Iran, Islamic Republic of); Moghadam, Somayeh Tiani [Chemistry Department, Arak University, P.O. Box 38156-879, Arak (Iran, Islamic Republic of); Jamehbozorg, Bahman [Department of Chemistry, University of Kurdistan, Sanandaj, Kurdistan 66135 (Iran, Islamic Republic of)

2011-10-15

Highlights: > Thermodynamics parameters for partitioning of L-methionine in ATPS. > Investigation of different effects on partition coefficient of the amino acid. > Propose the best condition for L-methionine partitioning. - Abstract: The partitioning behavior of L-methionine has been studied in aqueous two-phase systems of (poly(propylene glycol) + sodium phosphate salts + H{sub 2}O) at different temperatures. The salts used were sodium di-hydrogen phosphate (NaH{sub 2}PO{sub 4}), di-sodium hydrogen phosphate (Na{sub 2}HPO{sub 4}) and tri-sodium phosphate (Na{sub 3}PO{sub 4}). The effects of tie line length, salt type, and temperature on the partition coefficient of this amino acid have been studied. In addition, thermodynamic parameters ({Delta}H{sup o}, {Delta}S{sup o} and {Delta}G{sup o}) as a function of temperature were calculated. The results showed that increasing tie line length led to decreasing of the partition coefficient. We also showed that the partition coefficients of the amino acid in the systems containing Na{sub 3}PO{sub 4} are greater than the other two salts. Moreover, it is verified that increasing temperature led to decreasing the partition coefficient. The experimental partition coefficient data are correlated using a modified virial-type model.

Bioavailability of D-methionine relative to L-methionine for nursery pigs using the slope-ratio assay

Directory of Open Access Journals (Sweden)

Changsu Kong

2016-09-01

Full Text Available This experiment was conducted to determine the bioavailability of D-methionine (Met relative to L-Met for nursery pigs using the slope-ratio assay. A total of 50 crossbred barrows with an initial BW of 13.5 kg (SD = 1.0 were used in an N balance study. A Met-deficient basal diet (BD was formulated to contain an adequate amount of all amino acids (AA for 10–20 kg pigs except for Met. The two reference diets were prepared by supplementing the BD with 0.4 or 0.8 g L-Met/kg at the expense of corn starch, and an equivalent concentration of D-Met was added to the BD for the two test diets. The pigs were adapted to the experimental diets for 5 d and then total but separated collection of feces and urine was conducted for 4 d according to the marker-to-marker procedure. Nitrogen intakes were similar across the treatments. Fecal N output was not affected by Met supplementation regardless of source and consequently apparent N digestibility did not change. Conversely, there was a negative linear response (P < 0.01 to Met supplementation with both Met isomers in urinary N output, which resulted in increased retained N (g/4 d and N retention (% of intake. No quadratic response was observed in any of the N balance criteria. The estimated bioavailability of D-Met relative to L-Met from urinary N output (g/4 d and N retention (% of intake as dependent variables using supplemental Met intake (g/4 d as an independent variable were 87.6% and 89.6%, respectively; however, approximately 95% of the fiducial limits for the relative bioavailability estimates included 100%. In conclusion, with an absence of statistical significance, the present study indicated that the mean relative bioequivalence of D- to L-Met was 87.6% based on urinary N output or 89.6% based on N retention.

Expression of a methionine-rich storage albumin from the Brazil nut (Bertholletia excelsa H.B.K., Lecythidaceae in transgenic bean plants (Phaseolus vulgaris L., Fabaceae

Directory of Open Access Journals (Sweden)

Aragão F.J.L.

1999-01-01

Full Text Available Bean (Phaseolus vulgaris, an important component in the diet of people in developing countries, has low levels of the essential amino acid, methionine. We have attempted to correct this deficiency by introducing a transgene coding for a methionine-rich storage albumin from the Brazil nut via biolistic methods. The transgene's coding sequence was driven by a doubled 35S CaMV promoter and AMV enhancer sequences. The transgene was stable and correctly expressed in homozygous R2 to R5 seeds. In two of the five transgenic lines the methionine content was significantly increased (14 and 23% over the values found in untransformed plants.

Peptide methionine sulfoxide reductase A (MsrA): direct electrochemical oxidation on carbon electrodes.

Science.gov (United States)

Enache, T A; Oliveira-Brett, A M

2013-02-01

The direct electrochemical behaviour of peptide methionine sulfoxide reductase A (MsrA) adsorbed on glassy carbon and boron doped diamond electrodes surface, was studied over a wide pH range by cyclic and differential pulse voltammetry. MsrA oxidation mechanism occurs in three consecutive, pH dependent steps, corresponding to the oxidation of tyrosine, tryptophan and histidine amino acid residues. At the glassy carbon electrode, the first step corresponds to the oxidation of tyrosine and tryptophan residues and occurs for the same potential. The advantage of boron doped diamond electrode was to enable the separation of tyrosine and tryptophan oxidation peaks. On the second step occurs the histidine oxidation, and on the third, at higher potentials, the second tryptophan oxidation. MsrA adsorbs on the hydrophobic carbon electrode surface preferentially through the three hydrophobic domains, C1, C2 and C3, which contain the tyrosine, tryptophan and histidine residues, and tryptophan exists only in these regions, and undergo electrochemical oxidation. Copyright © 2012 Elsevier B.V. All rights reserved.

Is L-methionine a trigger factor for Alzheimer?s-like neurodegeneration?: Changes in A? oligomers, tau phosphorylation, synaptic proteins, Wnt signaling and behavioral impairment in wild-type mice

OpenAIRE

Tapia-Rojas, Cheril; Lindsay, Carolina B.; Montecinos-Oliva, Carla; Arrazola, Macarena S.; Retamales, Rocio M.; Bunout, Daniel; Hirsch, Sandra; Inestrosa, Nibaldo C.

2015-01-01

Background L-methionine, the principal sulfur-containing amino acid in proteins, plays critical roles in cell physiology as an antioxidant and in the breakdown of fats and heavy metals. Previous studies suggesting the use of L-methionine as a treatment for depression and other diseases indicate that it might also improve memory and propose a role in brain function. However, some evidence indicates that an excess of methionine can be harmful and can increase the risk of developing Type-2 diabe...

Effect of Dietary Crude Protein and Methionine on Egg Production and Egg Quality of Laying Hens During Phase II

Directory of Open Access Journals (Sweden)

H Mohammadi Emarat

2012-02-01

Full Text Available An experiment was conducted to evaluate the effect of dietary crude protein and methionine levels on quality and quantity of egg production. Fifteen diets formulated with 3 levels of protein (13, 14 and 15% and 5 levels of methionine (0.25, 0.28, 0.31, 0.34 and 0.37% and fed to 420 birds in a 3×5 factorial arrangement. Each diet was randomly fed to 4 replicates of 7 birds each and fed for 3 periods of 4 weeks (50-62wks of age each. Egg number and mortality was recorded daily, whereas feed consumption determined at the end of each period. The increased in dietary protein significantly increased egg production from 54 to 59.4 %. Egg weight, egg mass and feed intake increased by 1.7 g, 3.4 g, and 2.8 g, respectively during the whole experimental period. As the dietary protein increased, feed conversion, egg component (as a percent of whale egg and egg albumin percent were improved. However, the egg breaking, specific gravity and eggshell were significantly decreased with increased dietary protein. The egg yolk percent was not influenced by dietary protein levels. The increased in dietary methionine from 0.25% to 0.37% caused the overall egg production, egg weight, egg mass, feed intake and egg component to improve by about 8.2%, 4g, 6.6g, 8.7g, and 6.0g, respectively. Feed conversion, specific gravity, egg breakage, egg shell, and egg yolk and albumin percent were not influenced by dietary methionine levels.

Methionine sulfoxides in serum proteins as potential clinical biomarkers of oxidative stress

OpenAIRE

Satoko Suzuki; Yoshio Kodera; Tatsuya Saito; Kazumi Fujimoto; Akari Momozono; Akinori Hayashi; Yuji Kamata; Masayoshi Shichiri

2016-01-01

Oxidative stress contributes to the pathophysiology of a variety of diseases, and circulating biomarkers of its severity remains a topic of great interest for researchers. Our peptidomic strategy enables accurate and reproducible analysis of circulating proteins/peptides with or without post-translational modifications. Conventional wisdom holds that hydrophobic methionines exposed to an aqueous environment or experimental handling procedures are vulnerable to oxidation. However, we show that...

Localization of nitric oxide synthase in human skeletal muscle

DEFF Research Database (Denmark)

Frandsen, Ulrik; Lopez-Figueroa, M.; Hellsten, Ylva

1996-01-01

The present study investigated the cellular localization of the neuronal type I and endothelial type III nitric oxide synthase in human skeletal muscle. Type I NO synthase immunoreactivity was found in the sarcolemma and the cytoplasm of all muscle fibres. Stronger immunoreactivity was expressed...

Does the oxidation of methionine residue precede the inactivation of the trypsin inhibitor (LUTI in germinating seeds of common flax (Linum usitatissimum?

Directory of Open Access Journals (Sweden)

Irena Lorenc-Kubis

2011-01-01

Full Text Available Antitrypsin activity in germinating common seeds of flax (Linum usitatissimum was investigated. At the early stage of germination an increase in antitrypsin activity was observed, followed by its decrease during the development of the seedlings. From 6-day-old seedlings a trypsin inhibitor (gerLUTI was purified. The purification procedure involved fractionation of proteins from seedling homogenate with alcohol and successive chromatography on CM-Sephadex C-25 on immobilised methylchymotrypsin in the presence of 5 M NaCl, and finally on a C18 column in RP-HPLC. The gerLUTI migrated in SDS PAGE as a single band, but in mass spectroscopy analysis it exhibited the presence of at least three forms with molecular masses of 7654 ± 3 Da, 7668/7670 ± 3 Da, and 7687 ± 3 Da. The preparation of LUTI isolated from resting seeds contained only one form, with a molecular mass of 7655 ± 3 Da. LUTI and gerLUTI differed also in methionine contents. LUTI contained two methionine residues, whereas in gerLUTI only a trace of methionine was detected. The obtained results might suggest that during flax seeds germination the inhibitor molecules undergo selective modification, e.g. oxidation at methionine residues, before being degraded by proteolytic enzymes.

Detection of MTRR 66A→G polymorphism using real-time polymerase chain reaction machine LightCycler for determination of composition of allele after restriction cleavage

DEFF Research Database (Denmark)

Tvedegaard, Kristine Carstens; Pedersen, Bent Nørgaard; Rüdiger, Niels

2006-01-01

The MTRR gene codes for methionine synthase reductase, one of the enzymes involved in the conversion of homocysteine to methionine. This conversion influences the overall level of total plasma homocysteine (tHcy) and mutations, which reduces the enzyme activity and results in an increased concent...... of having a foetus with neural tube defects. We have established a method for analysing MTRR 66A>G on DNA from dried blood spots using melting temperature analysis. The DNA was extracted from dried blood spots using a fast procedure by boiling only....

Sucrose Phosphate Synthase and Sucrose Accumulation at Low Temperature 1

Science.gov (United States)

Guy, Charles L.; Huber, Joan L. A.; Huber, Steven C.

1992-01-01

The influence of growth temperature on the free sugar and sucrose phosphate synthase content and activity of spinach (Spinacia oleracea) leaf tissue was studied. When plants were grown at 25°C for 3 weeks and then transferred to a constant 5°C, sucrose, glucose, and fructose accumulated to high levels during a 14-d period. Predawn sugar levels increased from 14- to 20-fold over the levels present at the outset of the low-temperature treatment. Sucrose was the most abundant free sugar before, during, and after exposure to 5°C. Leaf sucrose phosphate synthase activity was significantly increased by the low-temperature treatment, whereas sucrose synthase and invertases were not. Synthesis of the sucrose phosphate synthase subunit was increased during and after low-temperature exposure and paralleled an increase in the steady-state level of the subunit. The increases in sucrose and its primary biosynthetic enzyme, sucrose phosphate synthase, are discussed in relation to adjustment of metabolism to low nonfreezing temperature and freezing stress tolerance. Images Figure 1 Figure 2 Figure 3 PMID:16652990

Glycine N-methyltransferase deficiency: a novel inborn error causing persistent isolated hypermethioninaemia.

NARCIS (Netherlands)

Mudd, S.H.; Cerone, R.; Schiaffino, M.C.; Fantasia, A.R.; Minniti, G.; Caruso, U.; Lorini, R.; Watkins, D.; Matiaszuk, N.; Rosenblatt, D.S.; Schwahn, B.; Rozen, R.; Gros, L. Le; Kotb, M.; Capdevila, A.; Luka, Z.; Finkelstein, J.; Tangerman, A.; Stabler, S.P.; Allen, R.; Wagner, C.

2001-01-01

This paper reports clinical and metabolic studies of two Italian siblings with a novel form of persistent isolated hypermethioninaemia, i.e. abnormally elevated plasma methionine that lasted beyond the first months of life and is not due to cystathionine beta-synthase deficiency, tyrosinaemia I or

Association of a 31 bp VNTR in the CBS gene with postload homocysteine concentrations in the Framingham Offspring Study.

NARCIS (Netherlands)

Lievers, K.J.; Kluijtmans, L.A.J.; Blom, H.J.; Wilson, P.W.; Selhub, J.; Ordovas, J.M.

2006-01-01

Elevated total plasma homocysteine concentrations (tHcy), both fasting and post-methionine load, have been established as risk factors for vascular disease. Recently, we described the association of a 31 bp variable number of tandem repeats (VNTR) in the cystathionine beta-synthase (CBS) gene with

[BIOINFORMATIC SEARCH AND PHYLOGENETIC ANALYSIS OF THE CELLULOSE SYNTHASE GENES OF FLAX (LINUM USITATISSIMUM)].

Science.gov (United States)

Pydiura, N A; Bayer, G Ya; Galinousky, D V; Yemets, A I; Pirko, Ya V; Podvitski, T A; Anisimova, N V; Khotyleva, L V; Kilchevsky, A V; Blume, Ya B

2015-01-01

A bioinformatic search of sequences encoding cellulose synthase genes in the flax genome, and their comparison to dicots orthologs was carried out. The analysis revealed 32 cellulose synthase gene candidates, 16 of which are highly likely to encode cellulose synthases, and the remaining 16--cellulose synthase-like proteins (Csl). Phylogenetic analysis of gene products of cellulose synthase genes allowed distinguishing 6 groups of cellulose synthase genes of different classes: CesA1/10, CesA3, CesA4, CesA5/6/2/9, CesA7 and CesA8. Paralogous sequences within classes CesA1/10 and CesA5/6/2/9 which are associated with the primary cell wall formation are characterized by a greater similarity within these classes than orthologous sequences. Whereas the genes controlling the biosynthesis of secondary cell wall cellulose form distinct clades: CesA4, CesA7, and CesA8. The analysis of 16 identified flax cellulose synthase gene candidates shows the presence of at least 12 different cellulose synthase gene variants in flax genome which are represented in all six clades of cellulose synthase genes. Thus, at this point genes of all ten known cellulose synthase classes are identify in flax genome, but their correct classification requires additional research.