Ubiquitin Regulates GGA3-mediated Degradation of BACE1*

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Kang, Eugene L.; Cameron, Andrew N.; Piazza, Fabrizio; Walker, Kendall R.; Tesco, Giuseppina

2010-01-01

BACE1 (β-site amyloid precursor protein-cleaving enzyme 1) is a membrane-tethered member of the aspartyl proteases, essential for the production of β-amyloid, a toxic peptide that accumulates in the brain of subjects affected by Alzheimer disease. The BACE1 C-terminal fragment contains a DXXLL motif that has been shown to bind the VHS (VPS27, Hrs, and STAM) domain of GGA1–3 (Golgi-localized γ-ear-containing ARF-binding proteins). GGAs are trafficking molecules involved in the transport of proteins containing the DXXLL signal from the Golgi complex to endosomes. Moreover, GGAs bind ubiquitin and traffic synthetic and endosomal ubiquitinated cargoes to lysosomes. We have previously shown that depletion of GGA3 results in increased BACE1 levels and activity because of impaired lysosomal degradation. Here, we report that the accumulation of BACE1 is rescued by the ectopic expression of GGA3 in H4 neuroglioma cells depleted of GGA3. Accordingly, the overexpression of GGA3 reduces the levels of BACE1 and β-amyloid. We then established that mutations in the GGA3 VPS27, Hrs, and STAM domain (N91A) or in BACE1 di-leucine motif (L499A/L500A), able to abrogate their binding, did not affect the ability of ectopically expressed GGA3 to rescue BACE1 accumulation in cells depleted of GGA3. Instead, we found that BACE1 is ubiquitinated at lysine 501 and is mainly monoubiquitinated and Lys-63-linked polyubiquitinated. Finally, a GGA3 mutant with reduced ability to bind ubiquitin (GGA3L276A) was unable to regulate BACE1 levels both in rescue and overexpression experiments. These findings indicate that levels of GGA3 tightly and inversely regulate BACE1 levels via interaction with ubiquitin sorting machinery. PMID:20484053

β-Secretase BACE1 Promotes Surface Expression and Function of Kv3.4 at Hippocampal Mossy Fiber Synapses.

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Hartmann, Stephanie; Zheng, Fang; Kyncl, Michele C; Karch, Sandra; Voelkl, Kerstin; Zott, Benedikt; D'Avanzo, Carla; Lomoio, Selene; Tesco, Giuseppina; Kim, Doo Y; Alzheimer, Christian; Huth, Tobias

2018-04-04

The β-secretase β-site APP-cleaving enzyme 1 (BACE1) is deemed a major culprit in Alzheimer's disease, but accumulating evidence indicates that there is more to the enzyme than driving the amyloidogenic processing of the amyloid precursor protein. For example, BACE1 has emerged as an important regulator of neuronal activity through proteolytic and, most unexpectedly, also through nonproteolytic interactions with several ion channels. Here, we identify and characterize the voltage-gated K + channel 3.4 (Kv3.4) as a new and functionally relevant interaction partner of BACE1. Kv3.4 gives rise to A-type current with fast activating and inactivating kinetics and serves to repolarize the presynaptic action potential. We found that BACE1 and Kv3.4 are highly enriched and remarkably colocalized in hippocampal mossy fibers (MFs). In BACE1 -/- mice of either sex, Kv3.4 surface expression was significantly reduced in the hippocampus and, in synaptic fractions thereof, Kv3.4 was specifically diminished, whereas protein levels of other presynaptic K + channels such as K Ca 1.1 and K Ca 2.3 remained unchanged. The apparent loss of presynaptic Kv3.4 affected the strength of excitatory transmission at the MF-CA3 synapse in hippocampal slices of BACE1 -/- mice when probed with the Kv3 channel blocker BDS-I. The effect of BACE1 on Kv3.4 expression and function should be bidirectional, as predicted from a heterologous expression system, in which BACE1 cotransfection produced a concomitant upregulation of Kv3.4 surface level and current based on a physical interaction between the two proteins. Our data show that, by targeting Kv3.4 to presynaptic sites, BACE1 endows the terminal with a powerful means to regulate the strength of transmitter release. SIGNIFICANCE STATEMENT The β-secretase β-site APP-cleaving enzyme 1 (BACE1) is infamous for its crucial role in the pathogenesis of Alzheimer's disease, but its physiological functions in the intact nervous system are only gradually

Reversing hypomyelination in BACE1-null mice with Akt-DD overexpression.

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Hu, Xiangyou; Schlanger, Rita; He, Wanxia; Macklin, Wendy B; Yan, Riqiang

2013-05-01

β-Site amyloid precursor protein convertase enzyme 1 (BACE1), a type I transmembrane aspartyl protease required to cleave amyloid precursor protein for releasing a toxic amyloid peptide, also cleaves type I and type III neuregulin-1 (Nrg-1). BACE1 deficiency in mice causes hypomyelination during development and impairs remyelination if injured. In BACE1-null mice, the abolished cleavage of neuregulin-1 by BACE1 is speculated to cause reduced myelin sheath thickness in both the central nervous system and peripheral nervous system because reduced cleavage of Nrg-1 correlates with reduced Akt phosphorylation, a downstream signaling molecule of the Nrg-1/ErbB pathway. Here we tested specifically whether increasing Akt activity alone in oligodendrocytes would be sufficient to reverse the hypomyelination phenotype in BACE1-null mice. BACE1-null mice were bred with transgenic mice expressing constitutively active Akt (Akt-DD; mutations with D(308)T and D(473)S) in oligodendrocytes. Relative to littermate BACE1-null controls, BACE1(-/-)/Akt-DD mice exhibited enhanced expression of myelin basic protein and promoter of proteolipid protein. The elevated expression of myelin proteins correlated with a thicker myelin sheath in optic nerves; comparison of quantified g ratios with statistic significance was used to confirm this reversion. However, it appeared that myelin sheath thickness in the sciatic nerves was not increased in BACE1(-/-)/Akt-DD mice, as the g ratio was not significantly different from the control. Hence, increased Akt activity in BACE1-null myelinating cells only compensates for the loss of BACE1 activity in the central nervous system, which is consistent with the observation that overexpression of Akt-DD in Schwann cells did not induce hypermyelination. Our results suggest that signaling activity other than Akt may also contribute to proper myelination in peripheral nerves.

Developing BACE-1 inhibitors for FXS

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Cara J Westmark

2013-05-01

Full Text Available Fragile X syndrome (FXS is a debilitating genetic disorder with no cure and few therapeutic options. Excessive signaling through metabotropic glutamate receptor 5 (mGluR5 in FXS leads to increased translation of numerous synaptic proteins and exaggerated long-term depression (LTD. Two of the overexpressed proteins are amyloid-beta protein precursor (APP and its metabolite amyloid-beta (Aβ, which have been well-studied in Alzheimer’s disease (AD. Here we discus the possibility that pharmaceuticals under study for the modulation of these proteins in AD might be viable therapeutic strategies for FXS. Specifically, a recently identified acetyltransferase (ATase inhibitor that reduces the levels and activity of β-site APP cleaving enzyme (BACE-1 has strong potential to attenuate BACE-1 activity and maintain homeostatic levels APP catabolites in FXS.

Oleic acid and linoleic acid from Tenebrio molitor larvae inhibit BACE1 activity in vitro: molecular docking studies.

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Youn, Kumju; Yun, Eun-Young; Lee, Jinhyuk; Kim, Ji-Young; Hwang, Jae-Sam; Jeong, Woo-Sik; Jun, Mira

2014-02-01

In our ongoing research to find therapeutic compounds for Alzheimer's disease (AD) from natural resources, the inhibitory activity of the BACE1 enzyme by Tenebrio molitor larvae and its major compounds were evaluated. The T. molitor larvae extract and its fractions exhibited strong BACE1 suppression. The major components of hexane fraction possessing both high yield and strong BACE1 inhibition were determined by thin layer chromatography, gas chromatography, and nuclear magnetic resonance analysis. A remarkable composition of unsaturated long chain fatty acids, including oleic acid and linoleic acid, were identified. Oleic acid, in particular, noncompetitively attenuated BACE1 activity with a half-maximal inhibitory concentration (IC₅₀) value of 61.31 μM and Ki value of 34.3 μM. Furthermore, the fatty acids were stably interacted with BACE1 at different allosteric sites of the enzyme bound with the OH of CYS319 and the NH₃ of TYR320 for oleic acid and with the C=O group of GLN304 for linoleic acid. Here, we first revealed novel pharmacophore features of oleic acids and linoleic acid to BACE1 by in silico docking studies. The present findings would clearly suggest potential guidelines for designing novel BACE1 selective inhibitors.

A PM7 dynamic residue-ligand interactions energy landscape of the BACE1 inhibitory pathway by hydroxyethylamine compounds. Part I: The flap closure process.

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Gueto-Tettay, Carlos; Martinez-Consuegra, Alejandro; Zuchniarz, Joshua; Gueto-Tettay, Luis Roberto; Drosos-Ramírez, Juan Carlos

2017-09-01

BACE1 is an enzyme of scientific interest because it participates in the progression of Alzheimer's disease. Hydroxyethylamines (HEAs) are a family of compounds which exhibit inhibitory activity toward BACE1 at a nanomolar level, favorable pharmacokinetic properties and oral bioavailability. The first step in the inhibition of BACE1 by HEAs consists of their entrance into the protease active site and the resultant conformational change in the protein, from Apo to closed form. These two conformations differ in the position of an antiparallel loop (called the flap) which covers the entrance to the catalytic site. For BACE1, closure of this flap is vital to its catalytic activity and to inhibition of the enzyme due to the new interactions thereby formed with the ligand. In the present study a dynamic energy landscape of residue-ligand interaction energies (ReLIE) measured for 112 amino acids in the BACE1 active site and its immediate vicinity during the closure of the flap induced by 8 HEAs of different inhibitory power is presented. A total of 6.272 million ReLIE calculations, based on the PM7 semiempirical method, provided a deep and quantitative view of the first step in the inhibition of the aspartyl protease. The information suggests that residues Asp93, Asp289, Thr292, Thr293, Asn294 and Arg296 are anchor points for the ligand, accounting for approximately 45% of the total protein-ligand interaction. Additionally, flap closure improved the BACE1-HEA interaction by around 25%. Furthermore, the inhibitory activity of HEAs could be related to the capacity of these ligands to form said anchor point interactions and maintain them over time: the lack of some of these anchor interactions delayed flap closure or impeded it completely, or even caused the flap to reopen. The methodology employed here could be used as a tool to evaluate future structural modifications which lead to improvements in the favorability and stability of BACE1-HEA ReLIEs, aiding in the design of

Inhibition of BACE1 Activity by a DNA Aptamer in an Alzheimer's Disease Cell Model.

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Huiyu Liang

Full Text Available An initial step in amyloid-β (Aβ production includes amyloid precursor protein (APP cleavage via β-Site amyloid precursor protein cleaving enzyme 1 (BACE1. Increased levels of brain Aβ have been implicated in the pathogenesis of Alzheimer's disease (AD. Thus, β-secretase represents a primary target for inhibitor drug development in AD. In this study, aptamers were obtained from combinatorial oligonucleotide libraries using a technology referred to as systematic evolution of ligands by exponential enrichment (SELEX. A purified human BACE1 extracellular domain was used as a target to conduct an in vitro selection process using SELEX. Two DNA aptamers were capable of binding to BACE1 with high affinity and good specificity, with Kd values in the nanomolar range. We subsequently confirmed that one aptamer, A1, exhibited a distinct inhibitory effect on BACE1 activity in an AD cell model. We detected the effects of M17-APPsw cells that stably expressed Swedish mutant APP after aptamer A1 treatment. Aβ40 and Aβ42 concentrations secreted by M17-APPsw cells decreased intracellularly and in culture media. Furthermore, Western blot analysis indicated that sAPPβ expression significantly decreased in the A1 treated versus control groups. These findings support the preliminary feasibility of an aptamer evolved from a SELEX strategy to function as a potential BACE1 inhibitor. To our knowledge, this is the first study to acquire a DNA aptamer that exhibited binding specificity to BACE1 and inhibited its activity.

Neuronal human BACE1 knockin induces systemic diabetes in mice.

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Plucińska, Kaja; Dekeryte, Ruta; Koss, David; Shearer, Kirsty; Mody, Nimesh; Whitfield, Phillip D; Doherty, Mary K; Mingarelli, Marco; Welch, Andy; Riedel, Gernot; Delibegovic, Mirela; Platt, Bettina

2016-07-01

β-Secretase 1 (BACE1) is a key enzyme in Alzheimer's disease pathogenesis that catalyses the amyloidogenic cleavage of amyloid precursor protein (APP). Recently, global Bace1 deletion was shown to protect against diet-induced obesity and diabetes, suggesting that BACE1 is a potential regulator of glucose homeostasis. Here, we investigated whether increased neuronal BACE1 is sufficient to alter systemic glucose metabolism, using a neuron-specific human BACE1 knockin mouse model (PLB4). Glucose homeostasis and adiposity were determined by glucose tolerance tests and EchoMRI, lipid species were measured by quantitative lipidomics, and biochemical and molecular alterations were assessed by western blotting, quantitative PCR and ELISAs. Glucose uptake in the brain and upper body was measured via (18)FDG-PET imaging. Physiological and molecular analyses demonstrated that centrally expressed human BACE1 induced systemic glucose intolerance in mice from 4 months of age onward, alongside a fatty liver phenotype and impaired hepatic glycogen storage. This diabetic phenotype was associated with hypothalamic pathology, i.e. deregulation of the melanocortin system, and advanced endoplasmic reticulum (ER) stress indicated by elevated central C/EBP homologous protein (CHOP) signalling and hyperphosphorylation of its regulator eukaryotic translation initiation factor 2α (eIF2α). In vivo (18)FDG-PET imaging further confirmed brain glucose hypometabolism in these mice; this corresponded with altered neuronal insulin-related signalling, enhanced protein tyrosine phosphatase 1B (PTP1B) and retinol-binding protein 4 (RBP4) levels, along with upregulation of the ribosomal protein and lipid translation machinery. Increased forebrain and plasma lipid accumulation (i.e. ceramides, triacylglycerols, phospholipids) was identified via lipidomics analysis. Our data reveal that neuronal BACE1 is a key regulator of metabolic homeostasis and provide a potential mechanism for the high

Quantum mechanics study of the hydroxyethylamines-BACE-1 active site interaction energies

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Gueto-Tettay, Carlos; Drosos, Juan Carlos; Vivas-Reyes, Ricardo

2011-06-01

The identification of BACE-1, a key enzyme in the production of Amyloid-β (Aβ) peptides, generated by the proteolytic processing of amyloid precursor protein, was a major advance in the field of Alzheimer's disease as this pathology is characterized by the presence of extracellular senile plaques, mainly comprised of Aβ peptides. Hydroxyethylamines have demonstrated a remarkable potential, like candidate drugs, for this disease using BACE-1 as target. Density Functional Theory calculations were employed to estimate interaction energies for the complexes formed between the hydroxyethylamine derivated inhibitors and 24 residues in the BACE-1 active site. The collected data offered not only a general but a particular quantitative description that gives a deep insight of the interactions in the active site, showing at the same time how ligand structural variations affect them. Polar interactions are the major energetic contributors for complex stabilization and those ones with charged aspartate residues are highlighted, as they contribute over 90% of the total attractive interaction energy. Ligand-ARG296 residue interaction reports the most repulsive value and decreasing of the magnitude of this repulsion can be a key feature for the design of novel and more potent BACE-1 inhibitors. Also it was explained why sultam derivated BACE-1 inhibitors are better ones than lactam based. Hydrophobic interactions concentrated at S1 zone and other relevant repulsions and attractions were also evaluated. The comparison of two different theory levels (X3LYP and M062X) allowed to confirm the relevance of the detected interactions as each theory level has its own strength to depict the forces involved, as is the case of M062X which is better describing the hydrophobic interactions. Those facts were also evaluated and confirmed by comparing the quantitative trend, of selected ligand-residue interactions, with MP2 theory level as reference standard method for electrostatic plus

Palmitoylated APP Forms Dimers, Cleaved by BACE1.

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Raja Bhattacharyya

Full Text Available A major rate-limiting step for Aβ generation and deposition in Alzheimer's disease brains is BACE1-mediated cleavage (β-cleavage of the amyloid precursor protein (APP. We previously reported that APP undergoes palmitoylation at two cysteine residues (Cys186 and Cys187 in the E1-ectodomain. 8-10% of total APP is palmitoylated in vitro and in vivo. Palmitoylated APP (palAPP shows greater preference for β-cleavage than total APP in detergent resistant lipid rafts. Protein palmitoylation is known to promote protein dimerization. Since dimerization of APP at its E1-ectodomain results in elevated BACE1-mediated cleavage of APP, we have now investigated whether palmitoylation of APP affects its dimerization and whether this leads to elevated β-cleavage of the protein. Here we report that over 90% of palAPP is dimerized while only ~20% of total APP forms dimers. PalAPP-dimers are predominantly cis-oriented while total APP dimerizes in both cis- and trans-orientation. PalAPP forms dimers 4.5-times more efficiently than total APP. Overexpression of the palmitoylating enzymes DHHC7 and DHHC21 that increase palAPP levels and Aβ release, also increased APP dimerization in cells. Conversely, inhibition of APP palmitoylation by pharmacological inhibitors reduced APP-dimerization in coimmunoprecipitation and FLIM/FRET assays. Finally, in vitro BACE1-activity assays demonstrate that palmitoylation-dependent dimerization of APP promotes β-cleavage of APP in lipid-rich detergent resistant cell membranes (DRMs, when compared to total APP. Most importantly, generation of sAPPβ-sAPPβ dimers is dependent on APP-palmitoylation while total sAPPβ generation is not. Since BACE1 shows preference for palAPP dimers over total APP, palAPP dimers may serve as novel targets for effective β-cleavage inhibitors of APP as opposed to BACE1 inhibitors.

Linking vascular disorders and Alzheimer’s disease: Potential involvement of BACE1

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Cole, Sarah L.; Vassar, Robert

2012-01-01

The etiology of Alzheimer’s disease (AD) remains unknown. However, specific risk factors have been identified, and aging is the strongest AD risk factor. The majority of cardiovascular events occur in older people and a close relationship between vascular disorders and AD exists. Amyloid plaques, composed of the beta amyloid peptide (Aβ), are hallmark lesions in AD and evidence indicates that Aβ plays a central role in AD pathophysiology. The BACE1 enzyme is essential for Aβ generation, and BACE1 levels are elevated in AD brain. The cause(s) of this BACE1 elevation remains undetermined. Here we review the potential contribution of vascular disease to AD pathogenesis. We examine the putative vasoactive properties of Aβ and how the cellular changes associated with vascular disease may elevate BACE1 levels. Despite increasing evidence, the exact role(s) vascular disorders play in AD remains to be determined. However, given that vascular diseases can be addressed by lifestyle and pharmacologic interventions, the potential benefits of these therapies in delaying the clinical appearance and progression of AD may warrant investigation. PMID:18289733

Fluorescence Microspectroscopy for Testing the Dimerization Hypothesis of BACE1 Protein in Cultured HEK293 Cells

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Gardeen, Spencer; Johnson, Joseph L.; Heikal, Ahmed A.

2016-06-01

Alzheimer's Disease (AD) is a neurodegenerative disorder that results from the formation of beta-amyloid plaques in the brain that trigger the known symptoms of memory loss in AD patients. The beta-amyloid plaques are formed by the proteolytic cleavage of the amyloid precursor protein (APP) by the proteases BACE1 and gamma-secretase. These enzyme-facilitated cleavages lead to the production of beta-amyloid fragments that aggregate to form plaques, which ultimately lead to neuronal cell death. Recent detergent protein extraction studies suggest that BACE1 protein forms a dimer that has significantly higher catalytic activity than its monomeric counterpart. In this contribution, we examine the dimerization hypothesis of BACE1 in cultured HEK293 cells using complementary fluorescence spectroscopy and microscopy methods. Cells were transfected with a BACE1-EGFP fusion protein construct and imaged using confocal, and differential interference contrast to monitor the localization and distribution of intracellular BACE1. Complementary fluorescence lifetime and anisotropy measurements enabled us to examine the conformational and environmental changes of BACE1 as a function of substrate binding. Using fluorescence correlation spectroscopy, we also quantified the diffusion coefficient of BACE1-EGFP on the plasma membrane as a means to test the dimerization hypothesis as a fucntion of substrate-analog inhibitition. Our results represent an important first towards examining the substrate-mediated dimerization hypothesis of BACE1 in live cells.

Mild oxidative stress induces redistribution of BACE1 in non-apoptotic conditions and promotes the amyloidogenic processing of Alzheimer's disease amyloid precursor protein.

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Jiang-Li Tan

Full Text Available BACE1 is responsible for β-secretase cleavage of the amyloid precursor protein (APP, which represents the first step in the production of amyloid β (Aβ peptides. Previous reports, by us and others, have indicated that the levels of BACE1 protein and activity are increased in the brain cortex of patients with Alzheimer's disease (AD. The association between oxidative stress (OS and AD has prompted investigations that support the potentiation of BACE1 expression and enzymatic activity by OS. Here, we have established conditions to analyse the effects of mild, non-lethal OS on BACE1 in primary neuronal cultures, independently from apoptotic mechanisms that were shown to impair BACE1 turnover. Six-hour treatment of mouse primary cortical cells with 10-40 µM hydrogen peroxide did not significantly compromise cell viability but it did produce mild oxidative stress (mOS, as shown by the increased levels of reactive radical species and activation of p38 stress kinase. The endogenous levels of BACE1 mRNA and protein were not significantly altered in these conditions, whereas a toxic H2O2 concentration (100 µM caused an increase in BACE1 protein levels. Notably, mOS conditions resulted in increased levels of the BACE1 C-terminal cleavage product of APP, β-CTF. Subcellular fractionation techniques showed that mOS caused a major rearrangement of BACE1 localization from light to denser fractions, resulting in an increased distribution of BACE1 in fractions containing APP and markers for trans-Golgi network and early endosomes. Collectively, these data demonstrate that mOS does not modify BACE1 expression but alters BACE1 subcellular compartmentalization to favour the amyloidogenic processing of APP, and thus offer new insight in the early molecular events of AD pathogenesis.

Mechanistic insights into mode of action of potent natural antagonists of BACE-1 for checking Alzheimer’s plaque pathology

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Dhanjal, Jaspreet Kaur [School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067 (India); Goyal, Sukriti [Apaji Institute of Mathematics and Applied Computer Technology, Banasthali University, Tonk 304022, Rajasthan (India); Sharma, Sudhanshu [Department of Biotechnology, Delhi Technological University, New Delhi 110042 (India); Hamid, Rabia [Department of Biochemistry, University of Kashmir, Srinagar 190006 (India); Grover, Abhinav, E-mail: abhinavgr@gmail.com [School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067 (India)

2014-01-17

Highlights: •Accumulation of Aβ plaques is one of the major pathology associated with Alzheimer’s disease. •Inhibition of β-Secretase or BACE-1 offers a viable prospect to check the growth of these plaques. •A large virtual dataset of natural compounds was screened against BACE-1. •Top two hits were analyzed for thermodynamic and structural stability using MD simulations. •Their detailed binding mode of actions were elucidated. -- Abstract: Alzheimer’s is a neurodegenerative disorder resulting in memory loss and decline in cognitive abilities. Accumulation of extracellular beta amyloidal plaques is one of the major pathology associated with this disease. β-Secretase or BACE-1 performs the initial and rate limiting step of amyloidic pathway in which 37–43 amino acid long peptides are generated which aggregate to form plaques. Inhibition of this enzyme offers a viable prospect to check the growth of these plaques. Numerous efforts have been made in recent years for the generation of BACE-1 inhibitors but many of them failed during the preclinical or clinical trials due to drug related or drug induced toxicity. In the present work, we have used computational methods to screen a large dataset of natural compounds to search for small molecules having BACE-1 inhibitory activity with low toxicity to normal cells. Molecular dynamics simulations were performed to analyze molecular interactions between the screened compounds and the active residues of the enzyme. Herein, we report two natural compounds of inhibitory nature active against β-secretase enzyme of amyloidic pathway and are potent lead molecules against Alzheimer’s disease.

Mechanistic insights into mode of action of potent natural antagonists of BACE-1 for checking Alzheimer’s plaque pathology

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Dhanjal, Jaspreet Kaur; Goyal, Sukriti; Sharma, Sudhanshu; Hamid, Rabia; Grover, Abhinav

2014-01-01

Highlights: •Accumulation of Aβ plaques is one of the major pathology associated with Alzheimer’s disease. •Inhibition of β-Secretase or BACE-1 offers a viable prospect to check the growth of these plaques. •A large virtual dataset of natural compounds was screened against BACE-1. •Top two hits were analyzed for thermodynamic and structural stability using MD simulations. •Their detailed binding mode of actions were elucidated. -- Abstract: Alzheimer’s is a neurodegenerative disorder resulting in memory loss and decline in cognitive abilities. Accumulation of extracellular beta amyloidal plaques is one of the major pathology associated with this disease. β-Secretase or BACE-1 performs the initial and rate limiting step of amyloidic pathway in which 37–43 amino acid long peptides are generated which aggregate to form plaques. Inhibition of this enzyme offers a viable prospect to check the growth of these plaques. Numerous efforts have been made in recent years for the generation of BACE-1 inhibitors but many of them failed during the preclinical or clinical trials due to drug related or drug induced toxicity. In the present work, we have used computational methods to screen a large dataset of natural compounds to search for small molecules having BACE-1 inhibitory activity with low toxicity to normal cells. Molecular dynamics simulations were performed to analyze molecular interactions between the screened compounds and the active residues of the enzyme. Herein, we report two natural compounds of inhibitory nature active against β-secretase enzyme of amyloidic pathway and are potent lead molecules against Alzheimer’s disease

Effects of curcuminoids identified in rhizomes of Curcuma longa on BACE-1 inhibitory and behavioral activity and lifespan of Alzheimer’s disease Drosophila models

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2014-01-01

Background Alzheimer’s disease (AD) is the most common type of presenile and senile dementia. The human β-amyloid precursor cleavage enzyme (BACE-1) is a key enzyme responsible for amyloid plaque production, which implicates the progress and symptoms of AD. Here we assessed the anti-BACE-1 and behavioral activities of curcuminoids from rhizomes of Curcuma longa (Zingiberaceae), diarylalkyls curcumin (CCN), demethoxycurcumin (DMCCN), and bisdemethoxycurcumin (BDMCCN) against AD Drosophila melanogaster models. Methods Neuro-protective ability of the curcuminoids was assessed using Drosophila melanogaster model system overexpressing BACE-1 and its substrate APP in compound eyes and entire neurons. Feeding and climbing activity, lifespan, and morphostructural changes in fly eyes also were evaluated. Results BDMCCN has the strongest inhibitory activity toward BACE-1 with 17 μM IC50, which was 20 and 13 times lower than those of CCN and DMCCN respectively. Overexpression of APP/BACE-1 resulted in the progressive and measurable defects in morphology of eyes and locomotion. Remarkably, supplementing diet with either 1 mM BDMCCN or 1 mM CCN rescued APP/BACE1-expressing flies and kept them from developing both morphological and behavioral defects. Our results suggest that structural characteristics, such as degrees of saturation, types of carbon skeleton and functional group, and hydrophobicity appear to play a role in determining inhibitory potency of curcuminoids on BACE-1. Conclusion Further studies will warrant possible applications of curcuminoids as therapeutic BACE-1 blockers. PMID:24597901

G Protein-Coupled Receptors (GPCRs in Alzheimer’s Disease: A Focus on BACE1 Related GPCRs

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Juan eZhao

2016-03-01

Full Text Available The G protein coupled receptors (GPCRs have been considered as one of the largest families of validated drug targets, which involve in almost overall physiological functions and pathological processes. Meanwhile, Alzheimer’s disease (AD, the most common type of dementia, affects thinking, learning, memory and behavior of elderly people, that has become the hotspot nowadays for its increasing risks and incurability. The above fields have been intensively studied, and the link between the two has been demonstrated, whereas the way how GPCRs perturb AD progress are yet to be further explored given their complexities. In this review, we summarized recent progress regarding the GPCRs interacted with β-site APP cleaving enzyme 1 (BACE1, a key secretase in AD pathogenesis. Then we discussed the current findings on the regulatory roles of GPCRs on BACE1, and the possibility for pharmaceutical treatment of AD patients by the allosteric modulators and biased ligands of GPCRs. We hope this review can provide new insights into the understanding of mechanistic link between GPCRs and BACE1, and highlight the potential of GPCRs as therapeutic target for AD.

Structure-Based Design of an Iminoheterocyclic β-Site Amyloid Precursor Protein Cleaving Enzyme (BACE) Inhibitor that Lowers Central Aβ in Nonhuman Primates

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Mandal, Mihirbaran; Wu, Yusheng; Misiaszek, Jeffrey; Li, Guoqing; Buevich, Alexei; Caldwell, John P.; Liu, Xiaoxiang; Mazzola, Robert D.; Orth, Peter; Strickland, Corey; Voigt, Johannes; Wang, Hongwu; Zhu, Zhaoning; Chen, Xia; Grzelak, Michael; Hyde, Lynn A.; Kuvelkar, Reshma; Leach, Prescott T.; Terracina, Giuseppe; Zhang, Lili; Zhang, Qi; Michener, Maria S.; Smith, Brad; Cox, Kathleen; Grotz, Diane; Favreau, Leonard; Mitra, Kaushik; Kazakevich, Irina; McKittrick, Brian A.; Greenlee, William; Kennedy, Matthew E.; Parker, Eric M.; Cumming, Jared N.; Stamford, Andrew W. (Merck)

2016-04-14

We describe successful efforts to optimize the in vivo profile and address off-target liabilities of a series of BACE1 inhibitors represented by 6 that embodies the recently validated fused pyrrolidine iminopyrimidinone scaffold. Employing structure-based design, truncation of the cyanophenyl group of 6 that binds in the S3 pocket of BACE1 followed by modification of the thienyl group in S1 was pursued. Optimization of the pyrimidine substituent that binds in the S2'–S2'' pocket of BACE1 remediated time-dependent CYP3A4 inhibition of earlier analogues in this series and imparted high BACE1 affinity. These efforts resulted in the discovery of difluorophenyl analogue 9 (MBi-4), which robustly lowered CSF and cortex Aβ40 in both rats and cynomolgus monkeys following a single oral dose. Compound 9 represents a unique molecular shape among BACE inhibitors reported to potently lower central Aβ in nonrodent preclinical species.

Conformational Dynamics and Binding Free Energies of Inhibitors of BACE-1: From the Perspective of Protonation Equilibria.

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M Olivia Kim

2015-10-01

Full Text Available BACE-1 is the β-secretase responsible for the initial amyloidogenesis in Alzheimer's disease, catalyzing hydrolytic cleavage of substrate in a pH-sensitive manner. The catalytic mechanism of BACE-1 requires water-mediated proton transfer from aspartyl dyad to the substrate, as well as structural flexibility in the flap region. Thus, the coupling of protonation and conformational equilibria is essential to a full in silico characterization of BACE-1. In this work, we perform constant pH replica exchange molecular dynamics simulations on both apo BACE-1 and five BACE-1-inhibitor complexes to examine the effect of pH on dynamics and inhibitor binding properties of BACE-1. In our simulations, we find that solution pH controls the conformational flexibility of apo BACE-1, whereas bound inhibitors largely limit the motions of the holo enzyme at all levels of pH. The microscopic pKa values of titratable residues in BACE-1 including its aspartyl dyad are computed and compared between apo and inhibitor-bound states. Changes in protonation between the apo and holo forms suggest a thermodynamic linkage between binding of inhibitors and protons localized at the dyad. Utilizing our recently developed computational protocol applying the binding polynomial formalism to the constant pH molecular dynamics (CpHMD framework, we are able to obtain the pH-dependent binding free energy profiles for various BACE-1-inhibitor complexes. Our results highlight the importance of correctly addressing the binding-induced protonation changes in protein-ligand systems where binding accompanies a net proton transfer. This work comprises the first application of our CpHMD-based free energy computational method to protein-ligand complexes and illustrates the value of CpHMD as an all-purpose tool for obtaining pH-dependent dynamics and binding free energies of biological systems.

BACE1 protein endocytosis and trafficking are differentially regulated by ubiquitination at lysine 501 and the Di-leucine motif in the carboxyl terminus.

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Kang, Eugene L; Biscaro, Barbara; Piazza, Fabrizio; Tesco, Giuseppina

2012-12-14

β-Site amyloid precursor protein-cleaving enzyme (BACE1) is a membrane-tethered member of the aspartyl proteases that has been identified as β-secretase. BACE1 is targeted through the secretory pathway to the plasma membrane and then is internalized to endosomes. Sorting of membrane proteins to the endosomes and lysosomes is regulated by the interaction of signals present in their carboxyl-terminal fragment with specific trafficking molecules. The BACE1 carboxyl-terminal fragment contains a di-leucine sorting signal ((495)DDISLL(500)) and a ubiquitination site at Lys-501. Here, we report that lack of ubiquitination at Lys-501 (BACE1K501R) does not affect the rate of endocytosis but produces BACE1 stabilization and accumulation of BACE1 in early and late endosomes/lysosomes as well as at the cell membrane. In contrast, the disruption of the di-leucine motif (BACE1LLAA) greatly impairs BACE1 endocytosis and produces a delayed retrograde transport of BACE1 to the trans-Golgi network (TGN) and a delayed delivery of BACE1 to the lysosomes, thus decreasing its degradation. Moreover, the combination of the lack of ubiquitination at Lys-501 and the disruption of the di-leucine motif (BACE1LLAA/KR) produces additive effects on BACE1 stabilization and defective internalization. Finally, BACE1LLAA/KR accumulates in the TGN, while its levels are decreased in EEA1-positive compartments indicating that both ubiquitination at Lys-501 and the di-leucine motif are necessary for the trafficking of BACE1 from the TGN to early endosomes. Our studies have elucidated a differential role for the di-leucine motif and ubiquitination at Lys-501 in BACE1 endocytosis, trafficking, and degradation and suggest the involvement of multiple adaptor molecules.

BACE1 Protein Endocytosis and Trafficking Are Differentially Regulated by Ubiquitination at Lysine 501 and the Di-leucine Motif in the Carboxyl Terminus*

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Kang, Eugene L.; Biscaro, Barbara; Piazza, Fabrizio; Tesco, Giuseppina

2012-01-01

β-Site amyloid precursor protein-cleaving enzyme (BACE1) is a membrane-tethered member of the aspartyl proteases that has been identified as β-secretase. BACE1 is targeted through the secretory pathway to the plasma membrane and then is internalized to endosomes. Sorting of membrane proteins to the endosomes and lysosomes is regulated by the interaction of signals present in their carboxyl-terminal fragment with specific trafficking molecules. The BACE1 carboxyl-terminal fragment contains a di-leucine sorting signal (495DDISLL500) and a ubiquitination site at Lys-501. Here, we report that lack of ubiquitination at Lys-501 (BACE1K501R) does not affect the rate of endocytosis but produces BACE1 stabilization and accumulation of BACE1 in early and late endosomes/lysosomes as well as at the cell membrane. In contrast, the disruption of the di-leucine motif (BACE1LLAA) greatly impairs BACE1 endocytosis and produces a delayed retrograde transport of BACE1 to the trans-Golgi network (TGN) and a delayed delivery of BACE1 to the lysosomes, thus decreasing its degradation. Moreover, the combination of the lack of ubiquitination at Lys-501 and the disruption of the di-leucine motif (BACE1LLAA/KR) produces additive effects on BACE1 stabilization and defective internalization. Finally, BACE1LLAA/KR accumulates in the TGN, while its levels are decreased in EEA1-positive compartments indicating that both ubiquitination at Lys-501 and the di-leucine motif are necessary for the trafficking of BACE1 from the TGN to early endosomes. Our studies have elucidated a differential role for the di-leucine motif and ubiquitination at Lys-501 in BACE1 endocytosis, trafficking, and degradation and suggest the involvement of multiple adaptor molecules. PMID:23109336

Multi-structure docking analysis of BACE1 crystal structures and non-peptidic ligands.

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Haghighijoo, Zahra; Hemmateenejad, Bahram; Edraki, Najmeh; Miri, Ramin; Emami, Saeed

2017-09-01

In order to design novel non-peptidic inhibitors of BACE1, many research groups have attempted using computational studies including docking analyses. Since there are too many 3D structures for BACE1 in the protein database, the selection of suitable crystal structures is a key prerequisite for the successful application of molecular docking. We employed a multi-structure docking protocol. In which 615 ligands' structures were docked into 150 BACE1 structures. The large number of the resultant docking scores were post-processed by different data analysis methods including exploratory data analysis, regression analysis and discriminant analysis. It was found that using one crystal structure for docking did not result in high accuracy for predicting activity of the BACE1 inhibitors. Instead, using of the multi-structural docking scores, post-processed by chemometrics methods arrived to highly accurate predictive models. In this regards, the PDB accession codes of 4B70, 4DVF and 2WEZ could discriminate between active and inactive compounds, with higher accuracy. Clustering of the BACE1 structures based on principal component analysis of the crystallographic structures the revealed that the discriminant structures are in the center of the clusters. Thus, these structures can be selected as predominant crystal structures for docking studies of non-peptidic BACE1 inhibitors. Copyright © 2017 Elsevier Inc. All rights reserved.

Piperazine sulfonamide BACE1 inhibitors: Design, synthesis, and in vivo characterization

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Cumming, Jared; Babu, Suresh; Huang, Ying; Carrol, Carolyn; Chen, Xia; Favreau, Leonard; Greenlee, William; Guo, Tao; Kennedy, Matthew; Kuvelkar, Reshma; Le, Thuy; Li, Guoqing; McHugh, Nansie; Orth, Peter; Ozgur, Lynne; Parker, Eric; Saionz, Kurt; Stamford, Andrew; Strickland, Corey; Tadesse, Dawit; Voigta, Johannes; Zhang, Lili; Zhang, Qi (Ligand); (Merck)

2010-08-17

With collaboration between chemistry, X-ray crystallography, and molecular modeling, we designed and synthesized a series of novel piperazine sulfonamide BACE1 inhibitors. Iterative exploration of the non-prime side and S2{prime} sub-pocket of the enzyme culminated in identification of an analog that potently lowers peripheral A{beta}{sub 40} in transgenic mice with a single subcutaneous dose.

Anti-BACE1 and Antimicrobial Activities of Steroidal Compounds Isolated from Marine Urechis unicinctus

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Yong-Zhe Zhu; Jing-Wen Liu; Xue Wang; In-Hong Jeong; Young-Joon Ahn; Chuan-Jie Zhang

2018-01-01

The human β-site amyloid cleaving enzyme (BACE1) has been considered as an effective drug target for treatment of Alzheimer’s disease (AD). In this study, Urechis unicinctus (U. unicinctus), which is a Far East specialty food known as innkeeper worm, ethanol extract was studied by bioassay-directed fractionation and isolation to examine its potential β-site amyloid cleaving enzyme inhibitory and antimicrobial activity. The following compounds were characterized: hecogenin, cholest-4-en-3-one,...

Anti-BACE1 and Antimicrobial Activities of Steroidal Compounds Isolated from Marine Urechis unicinctus

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Yong-Zhe Zhu

2018-03-01

Full Text Available The human β-site amyloid cleaving enzyme (BACE1 has been considered as an effective drug target for treatment of Alzheimer’s disease (AD. In this study, Urechis unicinctus (U. unicinctus, which is a Far East specialty food known as innkeeper worm, ethanol extract was studied by bioassay-directed fractionation and isolation to examine its potential β-site amyloid cleaving enzyme inhibitory and antimicrobial activity. The following compounds were characterized: hecogenin, cholest-4-en-3-one, cholesta-4,6-dien-3-ol, and hurgadacin. These compounds were identified by their mass spectrometry, 1H, and 13C NMR spectral data, comparing those data with NIST/EPA/NIH Mass spectral database (NIST11 and published values. Hecogenin and cholest-4-en-3-one showed significant inhibitory activity against BACE1 with EC50 values of 116.3 and 390.6 µM, respectively. Cholesta-4,6-dien-3-ol and hurgadacin showed broad spectrum antimicrobial activity, particularly strongly against Escherichia coli (E. coli, Salmonella enterica (S. enterica, Pasteurella multocida (P. multocida, and Physalospora piricola (P. piricola, with minimal inhibitory concentration (MIC ranging from 0.46 to 0.94 mg/mL. This is the first report regarding those four known compounds that were isolated from U. unicinctus and their anti-BACE1 and antimicrobial activity, highlighting the fact that known natural compounds may be a critical source of new medicine leads. These findings provide scientific evidence for potential application of those bioactive compounds for the development of AD drugs and antimicrobial agents.

Anti-BACE1 and Antimicrobial Activities of Steroidal Compounds Isolated from Marine Urechis unicinctus.

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Zhu, Yong-Zhe; Liu, Jing-Wen; Wang, Xue; Jeong, In-Hong; Ahn, Young-Joon; Zhang, Chuan-Jie

2018-03-14

The human β-site amyloid cleaving enzyme (BACE1) has been considered as an effective drug target for treatment of Alzheimer's disease (AD). In this study, Urechis unicinctus (U. unicinctus) , which is a Far East specialty food known as innkeeper worm, ethanol extract was studied by bioassay-directed fractionation and isolation to examine its potential β-site amyloid cleaving enzyme inhibitory and antimicrobial activity. The following compounds were characterized: hecogenin, cholest-4- en -3-one, cholesta-4,6- dien -3-ol, and hurgadacin. These compounds were identified by their mass spectrometry, ¹H, and 13 C NMR spectral data, comparing those data with NIST/EPA/NIH Mass spectral database (NIST11) and published values. Hecogenin and cholest-4- en -3-one showed significant inhibitory activity against BACE1 with EC 50 values of 116.3 and 390.6 µM, respectively. Cholesta-4,6- dien -3-ol and hurgadacin showed broad spectrum antimicrobial activity, particularly strongly against Escherichia coli (E. coli) , Salmonella enterica (S. enterica) , Pasteurella multocida (P. multocida) , and Physalospora piricola (P. piricola) , with minimal inhibitory concentration (MIC) ranging from 0.46 to 0.94 mg/mL. This is the first report regarding those four known compounds that were isolated from U. unicinctus and their anti-BACE1 and antimicrobial activity, highlighting the fact that known natural compounds may be a critical source of new medicine leads. These findings provide scientific evidence for potential application of those bioactive compounds for the development of AD drugs and antimicrobial agents.

BACE1 Deficiency Causes Abnormal Neuronal Clustering in the Dentate Gyrus

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Hailong Hou

2017-07-01

Full Text Available BACE1 is validated as Alzheimer's β-secretase and a therapeutic target for Alzheimer's disease. In examining BACE1-null mice, we discovered that BACE1 deficiency develops abnormal clusters of immature neurons, forming doublecortin-positive neuroblasts, in the developing dentate gyrus, mainly in the subpial zone (SPZ. Such clusters were rarely observed in wild-type SPZ and not reported in other mouse models. To understand their origins and fates, we examined how neuroblasts in BACE1-null SPZ mature and migrate during early postnatal development. We show that such neuroblasts are destined to form Prox1-positive granule cells in the dentate granule cell layer, and mainly mature to form excitatory neurons, but not inhibitory neurons. Mechanistically, higher levels of reelin potentially contribute to abnormal neurogenesis and timely migration in BACE1-null SPZ. Altogether, we demonstrate that BACE1 is a critical regulator in forming the dentate granule cell layer through timely maturation and migration of SPZ neuroblasts.

Depletion of GGA1 and GGA3 mediates postinjury elevation of BACE1.

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Walker, Kendall R; Kang, Eugene L; Whalen, Michael J; Shen, Yong; Tesco, Giuseppina

2012-07-25

Traumatic brain injury (TBI) is one of the most robust environmental risk factors for Alzheimer's disease (AD). Compelling evidence is accumulating that a single event of TBI is associated with increased levels of Aβ. However, the underlying molecular mechanisms remain unknown. We report here that the BACE1 interacting protein, GGA3, is depleted while BACE1 levels increase in the acute phase after injury (48 h) in a mouse model of TBI. We further demonstrated the role of GGA3 in the regulation of BACE1 in vivo by showing that BACE1 levels are increased in the brain of GGA3-null mice. We next found that head trauma potentiates BACE1 elevation in GGA3-null mice in the acute phase after TBI, and discovered that GGA1, a GGA3 homolog, is a novel caspase-3 substrate depleted at 48 h after TBI. Moreover, GGA1 silencing potentiates BACE1 elevation induced by GGA3 deletion in neurons in vitro, indicating that GGA1 and GGA3 synergistically regulate BACE1. Accordingly, we found that levels of both GGA1 and GGA3 are depleted while BACE1 levels are increased in a series of postmortem AD brains. Finally, we show that GGA3 haploinsufficiency results in sustained elevation of BACE1 and Aβ levels while GGA1 levels are restored in the subacute phase (7 d) after injury. In conclusion, our data indicate that depletion of GGA1 and GGA3 engender a rapid and robust elevation of BACE1 in the acute phase after injury. However, the efficient disposal of the acutely accumulated BACE1 solely depends on GGA3 levels in the subacute phase of injury.

Caspase-3 cleavage of GGA3 stabilizes BACE: implications for Alzheimer's disease.

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Vassar, Robert

2007-06-07

BACE initiates the production of beta-amyloid (Abeta), the likely cause of Alzheimer's disease (AD). In this issue of Neuron, Tesco et al. show that during apoptosis caspase-3 cleaves the adaptor protein GGA3, which is required for BACE lysosomal degradation, consequently stabilizing BACE and elevating Abeta generation.

BACE1 Is Necessary for Experience-Dependent Homeostatic Synaptic Plasticity in Visual Cortex

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Emily Petrus

2014-01-01

Full Text Available Alzheimer’s disease (AD is the most common form of age-related dementia, which is thought to result from overproduction and/or reduced clearance of amyloid-beta (Aβ peptides. Studies over the past few decades suggest that Aβ is produced in an activity-dependent manner and has physiological relevance to normal brain functions. Similarly, physiological functions for β- and γ-secretases, the two key enzymes that produce Aβ by sequentially processing the amyloid precursor protein (APP, have been discovered over recent years. In particular, activity-dependent production of Aβ has been suggested to play a role in homeostatic regulation of excitatory synaptic function. There is accumulating evidence that activity-dependent immediate early gene Arc is an activity “sensor,” which acts upstream of Aβ production and triggers AMPA receptor endocytosis to homeostatically downregulate the strength of excitatory synaptic transmission. We previously reported that Arc is critical for sensory experience-dependent homeostatic reduction of excitatory synaptic transmission in the superficial layers of visual cortex. Here we demonstrate that mice lacking the major neuronal β-secretase, BACE1, exhibit a similar phenotype: stronger basal excitatory synaptic transmission and failure to adapt to changes in visual experience. Our results indicate that BACE1 plays an essential role in sensory experience-dependent homeostatic synaptic plasticity in the neocortex.

BACE1-Dependent Neuregulin-1 Signaling: An Implication for Schizophrenia

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Zhengrong Zhang

2017-09-01

Full Text Available Schizophrenia is a chronic psychiatric disorder with a lifetime prevalence of about 1% in the general population. Recent studies have shown that Neuregulin-1 (Nrg1 is a candidate gene for schizophrenia. At least 15 alternative splicing of NRG1 isoforms all contain an extracellular epidermal growth factor (EGF-like domain, which is sufficient for Nrg1 biological activity including the formation of myelin sheaths and the regulation of synaptic plasticity. It is known that Nrg1 can be cleaved by β-secretase (BACE1 and the resulting N-terminal fragment (Nrg1-ntf binds to receptor tyrosine kinase ErbB4, which activates Nrg1/ErbB4 signaling. While changes in Nrg1 expression levels in schizophrenia still remain controversial, understanding the BACE1-cleaved Nrg1-ntf and Nrg1/ErbB4 signaling in schizophrenia neuropathogenesis is essential and important. In this review paper, we included three major parts: (1 Nrg1 structure and cleavage pattern by BACE1; (2 BACE1-dependent Nrg1 cleavage associated with schizophrenia in human studies; and (3 Animal studies of Nrg1 and BACE1 mutations with behavioral observations. Our review will provide a better understanding of Nrg1 in schizophrenia and a potential strategy for using BACE1 cleavage of Nrg1 as a unique biomarker for diagnosis, as well as a new therapeutic target, of schizophrenia.

Depletion of GGA1 and GGA3 mediates post-injury elevation of BACE1

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Walker, Kendall R.; Kang, Eugene L.; Whalen, Michael J.; Shen, Yong; Tesco, Giuseppina

2012-01-01

Traumatic brain injury (TBI) is one of the most robust environmental risk factors for Alzheimer’s disease (AD). Compelling evidence is accumulating that a single event of TBI is associated with increased levels of Aβ. However, the underlying molecular mechanisms remain unknown. We report here that the BACE1 interacting protein, GGA3, is depleted while BACE1 levels increase in the acute phase post-injury (48hrs) in a mouse model of TBI. We further demonstrated the role of GGA3 in the regulation of BACE1 in vivo by showing that BACE1 levels are increased in the brain of GGA3 null mice. We next found that head trauma potentiates BACE1 elevation in GGA3 null mice in the acute phase post-TBI and discovered that GGA1, a GGA3 homologue, is a novel caspase-3 substrate depleted at 48 hrs post-TBI. Moreover, GGA1 silencing potentiates BACE1 elevation induced by GGA3 deletion in neurons in vitro indicating that GGA1 and GGA3 synergistically regulate BACE1. Accordingly, we found that levels of both GGA1 and GGA3 are depleted while BACE1 levels are increased in a series of post-mortem AD brains. Finally, we show that GGA3 haploinsufficiency results in sustained elevation of BACE1 and Aβ levels while GGA1 levels are restored in the subacute phase (7 days) post-injury. In conclusion, our data indicate that depletion of GGA1 and GGA3 engender a rapid and robust elevation of BACE1 in the acute phase post-injury. However, the efficient disposal of the acutely accumulated BACE1 solely depends on GGA3 levels in the sub-acute phase of injury. PMID:22836275

HuD Regulates Coding and Noncoding RNA to Induce APP→Aβ Processing

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Min-Ju Kang

2014-06-01

Full Text Available The primarily neuronal RNA-binding protein HuD is implicated in learning and memory. Here, we report the identification of several HuD target transcripts linked to Alzheimer’s disease (AD pathogenesis. HuD interacted with the 3′ UTRs of APP mRNA (encoding amyloid precursor protein and BACE1 mRNA (encoding β-site APP-cleaving enzyme 1 and increased the half-lives of these mRNAs. HuD also associated with and stabilized the long noncoding (lncRNA BACE1AS, which partly complements BACE1 mRNA and enhances BACE1 expression. Consistent with HuD promoting production of APP and APP-cleaving enzyme, the levels of APP, BACE1, BACE1AS, and Aβ were higher in the brain of HuD-overexpressing mice. Importantly, cortex (superior temporal gyrus from patients with AD displayed significantly higher levels of HuD and, accordingly, elevated APP, BACE1, BACE1AS, and Aβ than did cortical tissue from healthy age-matched individuals. We propose that HuD jointly promotes the production of APP and the cleavage of its amyloidogenic fragment, Aβ.

β-Secretase BACE1 regulates hippocampal and reconstituted M-currents in a β-subunit-like fashion.

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Hessler, Sabine; Zheng, Fang; Hartmann, Stephanie; Rittger, Andrea; Lehnert, Sandra; Völkel, Meike; Nissen, Matthias; Edelmann, Elke; Saftig, Paul; Schwake, Michael; Huth, Tobias; Alzheimer, Christian

2015-02-25

The β-secretase BACE1 is widely known for its pivotal role in the amyloidogenic pathway leading to Alzheimer's disease, but how its action on transmembrane proteins other than the amyloid precursor protein affects the nervous system is only beginning to be understood. We report here that BACE1 regulates neuronal excitability through an unorthodox, nonenzymatic interaction with members of the KCNQ (Kv7) family that give rise to the M-current, a noninactivating potassium current with slow kinetics. In hippocampal neurons from BACE1(-/-) mice, loss of M-current enhanced neuronal excitability. We relate the diminished M-current to the previously reported epileptic phenotype of BACE1-deficient mice. In HEK293T cells, BACE1 amplified reconstituted M-currents, altered their voltage dependence, accelerated activation, and slowed deactivation. Biochemical evidence strongly suggested that BACE1 physically associates with channel proteins in a β-subunit-like fashion. Our results establish BACE1 as a physiologically essential constituent of regular M-current function and elucidate a striking new feature of how BACE1 impacts on neuronal activity in the intact and diseased brain. Copyright © 2015 the authors 0270-6474/15/353298-14$15.00/0.

Intracellular trafficking of the β-secretase and processing of amyloid precursor protein.

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Zhi, Pei; Chia, Pei Zhi Cheryl; Chia, Cheryl; Gleeson, Paul A

2011-09-01

The main component of the amyloid plaques found in the brains of those with Alzheimer's disease (AD) is a polymerized form of the β-amyloid peptide (Aβ) and is considered to play a central role in the pathogenesis of this neurodegenerative disorder. Aβ is derived from the proteolytic processing of the amyloid precursor protein (APP). Beta site APP-cleaving enzyme, BACE1 (also known as β-secretase) is a membrane-bound aspartyl protease responsible for the initial step in the generation of Aβ peptide and is thus a prime target for therapeutic intervention. Substantive evidence now indicates that the processing of APP by BACE1 is regulated by the intracellular sorting of the enzyme and, moreover, perturbations in these intracellular trafficking pathways have been linked to late-onset AD. In this review, we highlight the recent advances in the understanding of the regulation of the intracellular sorting of BACE1 and APP and illustrate why the trafficking of these cargos represent a key issue for understanding the membrane-mediated events associated with the generation of the neurotoxic Aβ products in AD. Copyright © 2011 International Union of Biochemistry and Molecular Biology, Inc.

Glimepiride attenuates Aβ production via suppressing BACE1 activity in cortical neurons.

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Liu, Feiyang; Wang, Yijin; Yan, Ming; Zhang, Luyong; Pang, Tao; Liao, Hong

2013-12-17

Numerous lines of evidence suggest a strong link between diabetes mellitus and Alzheimer's disease (AD). Impaired insulin signaling and insulin resistance occur not only in diabetes but also in the brain of AD. Recent evidence has indicated that peroxisome proliferator-activated receptor γ (PPARγ) agonists thiazolidinediones (TZDs) can decrease β-amyloid peptide (Aβ) deposition, which is the core component of senile plaques in AD, but the underlying mechanisms still remain unclear. In this study, we investigated whether glimepiride with PPARγ-stimulating activity, an oral anti-diabetic drug, has similar effects on Aβ production in primary cortical neurons. We demonstrated that glimepiride decreased extracellular Aβ40 and Aβ42 levels. The effect of glimepiride on reduction of Aβ40 generation was mediated by downregulation of β-site APP-cleaving enzyme 1 (BACE1) mRNA and protein expression, and by suppression of BACE1 activity. In addition, we found that high glucose condition enhanced Aβ40 production and glimepiride significantly decreased high glucose-induced Aβ40 production. Finally, a specific PPARγ antagonist GW9662 reversed glimepiride inhibitory effect on Aβ40 generation, suggesting a PPARγ-dependent mechanism may be involved. Our data indicated that glimepiride may serve as a promising drug for the treatment of AD associated with diabetes. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Fragment-based virtual screening approach and molecular dynamics simulation studies for identification of BACE1 inhibitor leads.

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Manoharan, Prabu; Ghoshal, Nanda

2018-05-01

Traditional structure-based virtual screening method to identify drug-like small molecules for BACE1 is so far unsuccessful. Location of BACE1, poor Blood Brain Barrier permeability and P-glycoprotein (Pgp) susceptibility of the inhibitors make it even more difficult. Fragment-based drug design method is suitable for efficient optimization of initial hit molecules for target like BACE1. We have developed a fragment-based virtual screening approach to identify/optimize the fragment molecules as a starting point. This method combines the shape, electrostatic, and pharmacophoric features of known fragment molecules, bound to protein conjugate crystal structure, and aims to identify both chemically and energetically feasible small fragment ligands that bind to BACE1 active site. The two top-ranked fragment hits were subjected for a 53 ns MD simulation. Principle component analysis and free energy landscape analysis reveal that the new ligands show the characteristic features of established BACE1 inhibitors. The potent method employed in this study may serve for the development of potential lead molecules for BACE1-directed Alzheimer's disease therapeutics.

Membrane-Associated Effects of Glucocorticoid on BACE1 Upregulation and Aβ Generation: Involvement of Lipid Raft-Mediated CREB Activation.

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Choi, Gee Euhn; Lee, Sei-Jung; Lee, Hyun Jik; Ko, So Hee; Chae, Chang Woo; Han, Ho Jae

2017-08-30

Glucocorticoid has been widely accepted to induce Alzheimer's disease, but the nongenomic effect of glucocorticoid on amyloid β (Aβ) generation has yet to be studied. Here, we investigated the effect of the nongenomic pathway induced by glucocorticoid on amyloid precursor protein processing enzymes as well as Aβ production using male ICR mice and human neuroblastoma SK-N-MC cells. Mice groups exposed to restraint stress or intracerebroventricular injection of Aβ showed impaired cognition, decreased intracellular glucocorticoid receptor (GR) level, but elevated level of membrane GR (mGR). In this respect, we identified the mGR-dependent pathway evoked by glucocorticoid using impermeable cortisol conjugated to BSA (cortisol-BSA) on SK-N-MC cells. Cortisol-BSA augmented the expression of β-site amyloid precursor protein cleaving enzyme 1 (BACE1), the level of C-terminal fragment β of amyloid precursor protein (C99) and Aβ production, which were maintained even after blocking intracellular GR. We also found that cortisol-BSA enhanced the interaction between mGR and Gαs, which colocalized in the lipid raft. The subsequently activated CREB by cortisol-BSA bound to the CRE site of the BACE1 promoter increasing its expression, which was downregulated by inhibiting CBP. Consistently, blocking CBP attenuated cognitive impairment and Aβ production induced by corticosterone treatment or intracerebroventricular injection of Aβ more efficiently than inhibiting intracellular GR in mice. In conclusion, glucocorticoid couples mGR with Gαs and triggers cAMP-PKA-CREB axis dependent on the lipid raft to stimulate BACE1 upregulation and Aβ generation. SIGNIFICANCE STATEMENT Patients with Alzheimer's disease (AD) have been growing sharply and stress is considered as the major environment factor of AD. Glucocorticoid is the primarily responsive factor to stress and is widely known to induce AD. However, most AD patients usually have impaired genomic pathway of glucocorticoid

Human recombinant beta-secretase immobilized enzyme reactor for fast hits' selection and characterization from a virtual screening library.

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De Simone, Angela; Mancini, Francesca; Cosconati, Sandro; Marinelli, Luciana; La Pietra, Valeria; Novellino, Ettore; Andrisano, Vincenza

2013-01-25

In the present work, a human recombinant BACE1 immobilized enzyme reactor (hrBACE1-IMER) has been applied for the sensitive fast screening of 38 compounds selected through a virtual screening approach. HrBACE1-IMER was inserted into a liquid chromatograph coupled with a fluorescent detector. A fluorogenic peptide substrate (M-2420), containing the β-secretase site of the Swedish mutation of APP, was injected and cleaved in the on-line HPLC-hrBACE1-IMER system, giving rise to the fluorescent product. The compounds of the library were tested for their ability to inhibit BACE1 in the immobilized format and to reduce the area related to the chromatographic peak of the fluorescent enzymatic product. The results were validated in solution by using two different FRET methods. Due to the efficient virtual screening methodology, more than fifty percent of the selected compounds showed a measurable inhibitory activity. One of the most active compound (a bis-indanone derivative) was characterized in terms of IC(50) and K(i) determination on the hrBACE1-IMER. Thus, the hrBACE1-IMER has been confirmed as a valid tool for the throughput screening of different chemical entities with potency lower than 30μM for the fast hits' selection and for mode of action determination. Copyright © 2012 Elsevier B.V. All rights reserved.

Potent and Selective BACE-1 Peptide Inhibitors Lower Brain Aβ Levels Mediated by Brain Shuttle Transport

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Nadine Ruderisch

2017-10-01

Full Text Available Therapeutic approaches to fight Alzheimer's disease include anti-Amyloidβ (Aβ antibodies and secretase inhibitors. However, the blood-brain barrier (BBB limits the brain exposure of biologics and the chemical space for small molecules to be BBB permeable. The Brain Shuttle (BS technology is capable of shuttling large molecules into the brain. This allows for new types of therapeutic modalities engineered for optimal efficacy on the molecular target in the brain independent of brain penetrating properties. To this end, we designed BACE1 peptide inhibitors with varying lipid modifications with single-digit picomolar cellular potency. Secondly, we generated active-exosite peptides with structurally confirmed dual binding mode and improved potency. When fused to the BS via sortase coupling, these BACE1 inhibitors significantly reduced brain Aβ levels in mice after intravenous administration. In plasma, both BS and non-BS BACE1 inhibitor peptides induced a significant time- and dose-dependent decrease of Aβ. Our results demonstrate that the BS is essential for BACE1 peptide inhibitors to be efficacious in the brain and active-exosite design of BACE1 peptide inhibitors together with lipid modification may be of therapeutic relevance.

Design, Synthesis and Evaluation of 3-(2-Aminoheterocycle-4-benzyloxyphenylbenzamide Derivatives as BACE-1 Inhibitors

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Lushan Yu

2013-03-01

Full Text Available Three series of 3-(2-aminoheterocycle-4-benzyloxyphenylbenzamide derivatives, 2-aminooxazoles, 2-aminothiazoles, and 2-amino-6H-1,3,4-thiadizines were designed, synthesized and evaluated as β-secretase (BACE-1 inhibitors. Preliminary structure-activity relationships revealed that the existence of a 2-amino-6H-1,3,4-thiadizine moiety and α-naphthyl group were favorable for BACE-1 inhibition. Among the synthesized compounds, 5e exhibited the most potent BACE-1 inhibitory activity, with an IC50 value of 9.9 μΜ and it exhibited high brain uptake potential in Madin-Darby anine kidney cell lines (MDCK and a Madin-Darby canine kidney-multidrug resistance 1 (MDCK-MDR1 model.

Design, synthesis and evaluation of 3-(2-aminoheterocycle)-4-benzyloxyphenylbenzamide derivatives as BACE-1 inhibitors.

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Shangguan, Shihao; Wang, Fei; Liao, Yong; Yu, Haiping; Li, Jia; Huang, Wenhai; Hu, Haihong; Yu, Lushan; Hu, Yongzhou; Sheng, Rong

2013-03-20

Three series of 3-(2-aminoheterocycle)-4-benzyloxyphenylbenzamide derivatives, 2-aminooxazoles, 2-aminothiazoles, and 2-amino-6H-1,3,4-thiadizines were designed, synthesized and evaluated as β-secretase (BACE-1) inhibitors. Preliminary structure-activity relationships revealed that the existence of a 2-amino-6H-1,3,4-thiadizine moiety and α-naphthyl group were favorable for BACE-1 inhibition. Among the synthesized compounds, 5e exhibited the most potent BACE-1 inhibitory activity, with an IC50 value of 9.9 μΜ and it exhibited high brain uptake potential in Madin-Darby anine kidney cell lines (MDCK) and a Madin-Darby canine kidney-multidrug resistance 1 (MDCK-MDR1) model.

Cholesterol-dependent energy transfer between fluorescent proteins-insights into protein proximity of APP and BACE1 in different membranes in Niemann-Pick type C disease cells.

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von Einem, Bjoern; Weber, Petra; Wagner, Michael; Malnar, Martina; Kosicek, Marko; Hecimovic, Silva; Arnim, Christine A F von; Schneckenburger, Herbert

2012-11-26

Förster resonance energy transfer (FRET) -based techniques have recently been applied to study the interactions between β-site APP-cleaving enzyme-GFP (BACE1-GFP) and amyloid precursor protein-mRFP (APP-mRFP) in U373 glioblastoma cells. In this context, the role of APP-BACE1 proximity in Alzheimer's disease (AD) pathogenesis has been discussed. FRET was found to depend on intracellular cholesterol levels and associated alterations in membrane stiffness. Here, NPC1 null cells (CHO-NPC1-/-), exhibiting increased cholesterol levels and disturbed cholesterol transport similar to that observed in Niemann-Pick type C disease (NPC), were used to analyze the influence of altered cholesterol levels on APP-BACE1 proximity. Fluorescence lifetime measurements of whole CHO-wild type (WT) and CHO-NPC1-/- cells (EPI-illumination microscopy), as well as their plasma membranes (total internal reflection fluorescence microscopy, TIRFM), were performed. Additionally, generalized polarization (GP) measurements of CHO-WT and CHO-NPC1-/- cells incubated with the fluorescence marker laurdan were performed to determine membrane stiffness of plasma- and intracellular-membranes. CHO-NPC1-/- cells showed higher membrane stiffness at intracellular- but not plasma-membranes, equivalent to cholesterol accumulation in late endosomes/lysosomes. Along with higher membrane stiffness, the FRET efficiency between BACE1-GFP and APP-mRFP was reduced at intracellular membranes, but not within the plasma membrane of CHO-NPC1-/-. Our data show that FRET combined with TIRF is a powerful technique to determine protein proximity and membrane fluidity in cellular models of neurodegenerative diseases.

Differential contributions of ApoE4 and female sex to BACE1 activity and expression mediate Aβ deposition and learning and memory in mouse models of Alzheimer’s disease

Directory of Open Access Journals (Sweden)

Xu eHou

2015-10-01

Full Text Available Alzheimer’s disease (AD, the most common form of dementia, disproportionately affects women in both prevalence and severity. This increased vulnerability to AD in women is strongly associated with age-related ovarian hormone loss and apolipoprotein E 4 allele (ApoE4, the most important genetic risk factor for sporadic AD. Up to date, the mechanism involved in the interaction between ApoE4 and sex/gender in AD is still unclear. This study evaluated the sex-dependent ApoE4 effects on learning and memory, Aβ deposition and potential mechanisms, using mice bearing both sporadic (ApoE4 and familial (APPSwe, PS1M146V, tauP301L; 3xTg AD risk factors and compared with sex- and age-matched 3xTg or nonTg mice. Compared to nonTg mice, transgenic mice of both sexes showed spatial learning and memory deficits in the radial arm water maze and novel arm discrimination tests at 20 months of age. However, at 10 months, only ApoE4/3xTg mice showed significant learning and memory impairment. Moreover, molecular studies of hippocampal tissue revealed significantly higher protein levels of Aβ species, β-site APP cleavage enzyme (BACE1 and Sp1, a transcription factor of BACE1, in female ApoE4/3xTg when compared with female nonTg, female 3xTg and male ApoE4/3xTg mice. Significantly increased BACE1 enzymatic activities were observed in both male and female mice carrying ApoE4; however, only the females showed significant higher BACE1 expressions. Together, these data suggest that ApoE4 allele is associated with increased BACE1 enzymatic activity, while female sex plays an important role in increasing BACE1 expression. The combination of both provides a molecular basis for high Aβ pathology and the resultant hippocampus-dependent learning and memory deficits in female ApoE4 carriers.

Target specific proteochemometric model development for BACE1 - protein flexibility and structural water are critical in virtual screening.

Science.gov (United States)

Manoharan, Prabu; Chennoju, Kiranmai; Ghoshal, Nanda

2015-07-01

BACE1 is an attractive target in Alzheimer's disease (AD) treatment. A rational drug design effort for the inhibition of BACE1 is actively pursued by researchers in both academic and pharmaceutical industries. This continued effort led to the steady accumulation of BACE1 crystal structures, co-complexed with different classes of inhibitors. This wealth of information is used in this study to develop target specific proteochemometric models and these models are exploited for predicting the prospective BACE1 inhibitors. The models developed in this study have performed excellently in predicting the computationally generated poses, separately obtained from single and ensemble docking approaches. The simple protein-ligand contact (SPLC) model outperforms other sophisticated high end models, in virtual screening performance, developed during this study. In an attempt to account for BACE1 protein active site flexibility information in predictive models, we included the change in the area of solvent accessible surface and the change in the volume of solvent accessible surface in our models. The ensemble and single receptor docking results obtained from this study indicate that the structural water mediated interactions improve the virtual screening results. Also, these waters are essential for recapitulating bioactive conformation during docking study. The proteochemometric models developed in this study can be used for the prediction of BACE1 inhibitors, during the early stage of AD drug discovery.

VPS35 regulates developing mouse hippocampal neuronal morphogenesis by promoting retrograde trafficking of BACE1

Directory of Open Access Journals (Sweden)

Chun-Lei Wang

2012-10-01

VPS35, a major component of the retromer, plays an important role in the selective endosome-to-Golgi retrieval of membrane proteins. Dysfunction of retromer is a risk factor for neurodegenerative disorders, but its function in developing mouse brain remains poorly understood. Here we provide evidence for VPS35 promoting dendritic growth and maturation, and axonal protein transport in developing mouse hippocampal neurons. Embryonic hippocampal CA1 neurons suppressing Vps35 expression by in utero electroporation of its micro RNAs displayed shortened apical dendrites, reduced dendritic spines, and swollen commissural axons in the neonatal stage, those deficits reflecting a defective protein transport/trafficking in developing mouse neurons. Further mechanistic studies showed that Vps35 depletion in neurons resulted in an impaired retrograde trafficking of BACE1 (β1-secretase and altered BACE1 distribution. Suppression of BACE1 expression in CA1 neurons partially rescued both dendritic and axonal deficits induced by Vps35-deficiency. These results thus demonstrate that BACE1 acts as a critical cargo of retromer in vitro and in vivo, and suggest that VPS35 plays an essential role in regulating apical dendritic maturation and in preventing axonal spheroid formation in developing hippocampal neurons.

Gadd153 and NF-κB crosstalk regulates 27-hydroxycholesterol-induced increase in BACE1 and β-amyloid production in human neuroblastoma SH-SY5Y cells.

Directory of Open Access Journals (Sweden)

Gurdeep Marwarha

Full Text Available β-amyloid (Aβ peptide, accumulation of which is a culprit for Alzheimer's disease (AD, is derived from the initial cleavage of amyloid precursor protein by the aspartyl protease BACE1. Identification of cellular mechanisms that regulate BACE1 production is of high relevance to the search for potential disease-modifying therapies that inhibit BACE1 to reduce Aβ accumulation and AD progression. In the present study, we show that the cholesterol oxidation product 27-hydroxycholesterol (27-OHC increases BACE1 and Aβ levels in human neuroblastoma SH-SY5Y cells. This increase in BACE1 involves a crosstalk between the two transcription factors NF-κB and the endoplasmic reticulum stress marker, the growth arrest and DNA damage induced gene-153 (gadd153, also called CHOP. We specifically show that 27-OHC induces a substantial increase in NF-κB binding to the BACE1 promoter and subsequent increase in BACE1 transcription and Aβ production. The NF-κB inhibitor, sc514, significantly attenuated the 27-OHC-induced increase in NF-κB-mediated BACE1 expression and Aβ genesis. We further show that the 27-OHC-induced NF-κB activation and increased NF-κB-mediated BACE1 expression is contingent on the increased activation of gadd153. Silencing gadd153 expression with siRNA alleviated the 27-OHC-induced increase in NF-κB activation, NF-κB binding to the BACE1 promoter, and subsequent increase in BACE1 transcription and Aβ production. We also show that increased levels of BACE1 in the triple transgenic mouse model for AD is preceded by gadd153 and NF-κB activation. In summary, our study demonstrates that gadd153 and NF-κB work in concert to regulate BACE1 expression. Agents that inhibit gadd153 activation and subsequent interaction with NF-κB might be promising targets to reduce BACE1 and Aβ overproduction and may ultimately serve as disease-modifying treatments for AD.

Potential anti-cholinesterase and β-site amyloid precursor protein cleaving enzyme 1 inhibitory activities of cornuside and gallotannins from Cornus officinalis fruits.

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Bhakta, Himanshu Kumar; Park, Chan Hum; Yokozawa, Takako; Tanaka, Takashi; Jung, Hyun Ah; Choi, Jae Sue

2017-07-01

Cholinesterase (ChE) and β-site amyloid precursor protein cleaving enzyme 1 (BACE1) inhibitors are promising agents for the treatment of Alzheimer's disease (AD). In the present study, we examined the inhibitory activity of seven compounds isolated from the fruits of Cornus officinalis, cornuside, polymeric proanthocyanidins, 1,2,3-tri-O-galloyl-β-D-glucose, 1,2,3,6-tetra-O-galloyl-β-D-glucose, tellimagrandin I, tellimagrandin II, and isoterchebin, against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and BACE1. All of the compounds displayed concentration-dependent in vitro inhibitory activity toward the ChEs and BACE1. Among them, tellimagrandin II exhibited the best inhibitory activity toward ChEs, whereas the best BACE1 inhibitor was 1,2,3,6-tetra-O-galloyl-β-D-glucose. Isoterchebin and polymeric proanthocyanidins were also significant ChE inhibitors. The kinetic and docking studies demonstrated that all compounds interacted with both the catalytic active sites and the peripheral anionic sites of the ChEs and BACE1. Tellimagrandin II, isoterchebin, and the polymeric proanthocyanidins exhibited concentration-dependent inhibition of peroxynitrite-mediated protein tyrosine nitration. In conclusion, we identified significant ChE and BACE1 inhibitors from Corni Fructus that could have value as new multi-targeted compounds for anti-AD agents.

Electrical conductivity and chemical stability of BaCe0· 8− xAxGd0 ...

Indian Academy of Sciences (India)

... K. BaCe0.7In0.1Gd0.2O3− and BaCe0.7Zr0.1Gd0.2O3− ceramics exhibit an excellent chemical stability against boiling water. Indium is a suitable doping element to promote the sintering densification and to enhance both electrical conductivity and chemical stability of Gd-doped BaCeO3 at operating temperatures.

Electrical conductivity and chemical stability of BaCe0·8−xAxGd0 ...

Indian Academy of Sciences (India)

−1 in air at 1073 K. BaCe0·7In0·1Gd0·2O3−δ and BaCe0·7Zr0·1Gd0·2O3−δ ceramics exhibit an ... cells convert chemical energy directly into electrical energy and their ... peratures in the presence of CO2 and water vapour (Haile. 2003 ...

Plasma long non-coding RNA BACE1 as a novel biomarker for diagnosis of Alzheimer disease.

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Feng, Liang; Liao, Yu-Ting; He, Jin-Cai; Xie, Cheng-Long; Chen, Si-Yan; Fan, Hui-Hui; Su, Zhi-Peng; Wang, Zhen

2018-01-09

Long non-coding RNA (LncRNA) have been reported to be involved in the pathogenesis of neurodegenerative diseases, but whether it can serve as a biomarker for Alzheimer disease (AD) is not yet known. The present study selected four specific LncRNA (17A, 51A, BACE1 and BC200) as possible AD biomarker. RT-qPCR was performed to validate the LncRNA. Receiver operating characteristic curve (ROC) and area under the ROC curve (AUC) were applied to study the potential of LncRNA as a biomarker in a population of 88 AD patients and 72 control individuals. We found that the plasma LncRNA BACE1 level of AD patients was significantly higher than that of healthy controls (p = 0.006). Plasma level of LncRNA 17A, 51A and BC200 did not show a significant difference between two groups (p = 0.098, p = 0.204 and p = 0.232, respectively). ROC curve analysis showed that LncRNA BACE1 was the best candidate of these LncRNA (95% CI: 0.553-0.781, p = 0.003). In addition, no correlation was found for expression of these LncRNA in both control and AD groups with age or MMSE scale (p > 0.05). Our present study compared the plasma level of four LncRNA between AD and non-AD patients, and found that the level of the BACE1 is increased in the plasma of AD patients and have a high specificity (88%) for AD, indicating BACE1 may be a potential candidate biomarker to predict AD.

Discovery of imidazopyridines containing isoindoline-1,3-dione framework as a new class of BACE1 inhibitors: Design, synthesis and SAR analysis.

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Azimi, Sara; Zonouzi, Afsaneh; Firuzi, Omidreza; Iraji, Aida; Saeedi, Mina; Mahdavi, Mohammad; Edraki, Najmeh

2017-09-29

Alzheimer's disease is characterized by chronic neurodegeneration leading to dementia. The main cause of neurodegeneration is considered to be the accumulation of amyloid-β. Inhibiting BACE1 is a well-studied approach to lower the burden of amyloid-β aggregates. We designed a series of imidazopyridines-based compounds bearing phthalimide moieties as inhibitors of BACE1. The compounds 8a-o were synthesized by the Groebke-Blackburn-Bienaymé three-component reaction of heteroaromatic amidines, aldehydes and isocyanides. Evaluating the BACE1 inhibitory effects of the synthesized compounds revealed that introducing an aminocyclohexyl moiety in the imidazopyridine core resulted in a significant improvement in its BACE1 inhibitory potential. In this regard, compound 8e was the most potent against BACE1 with an IC 50 value of 2.84 (±0.95) μM. Molecular docking revealed that the nitrogen atom of imidazopyridines and the oxygen atom of the phenoxypropyl linker were involved in hydrogen bound interactions with Asp228 and Asp32 of BACE1 active site, respectively. The phthalimide moiety oriented toward the flap pocket and interacted with phe108, lle110, Trp115, Ile118 through van der Waal's and hydrophobic interactions. These findings demonstrate that imidazopyridines-based compounds bearing phthalimide moiety have the potential to decrease amyloid-β levels and ameliorate the symptoms of Alzheimer's disease. Copyright © 2017. Published by Elsevier Masson SAS.

Sebestenoids A-D, BACE1 inhibitors from Cordia sebestena.

Science.gov (United States)

Dai, Jingqiu; Sorribas, Analia; Yoshida, Wesley Y; Williams, Philip G

2010-12-01

Bioassay-guided fractionation of an extract prepared from the fruits of Cordia sebestena led to the isolation of sebestenoids A-D (1-4). Their structures were elucidated on the basis of extensive NMR experiments and mass spectroscopic measurements. Compounds 1-4 exhibited moderate inhibition of the aspartic protease BACE1. Copyright © 2010 Elsevier Ltd. All rights reserved.

Multi-enzyme Process Modeling

DEFF Research Database (Denmark)

Andrade Santacoloma, Paloma de Gracia

are affected (in a positive or negative way) by the presence of the other enzymes and compounds in the media. In this thesis the concept of multi-enzyme in-pot term is adopted for processes that are carried out by the combination of enzymes in a single reactor and implemented at pilot or industrial scale...... features of the process and provides the information required to structure the process model by using a step-by-step procedure with the required tools and methods. In this way, this framework increases efficiency of the model development process with respect to time and resources needed (fast and effective....... In this way the model parameters that drives the main dynamic behavior can be identified and thus a better understanding of this type of processes. In order to develop, test and verify the methodology, three case studies were selected, specifically the bi-enzyme process for the production of lactobionic acid...

Fetzima (levomilnacipran), a drug for major depressive disorder as a dual inhibitor for human serotonin transporters and beta-site amyloid precursor protein cleaving enzyme-1.

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Rizvi, Syed Mohd Danish; Shaikh, Sibhghatulla; Khan, Mahiuddin; Biswas, Deboshree; Hameed, Nida; Shakil, Shazi

2014-01-01

Pharmacological management of Major Depressive Disorder includes the use of serotonin reuptake inhibitors which targets serotonin transporters (SERT) to increase the synaptic concentrations of serotonin. Beta-site amyloid precursor protein cleaving enzyme-1 (BACE-1) is responsible for amyloid β plaque formation. Hence it is an interesting target for Alzheimer's disease (AD) therapy. This study describes molecular interactions of a new Food and Drug Administration approved antidepressant drug named 'Fetzima' with BACE-1 and SERT. Fetzima is chemically known as levomilnacipran. The study has explored a possible link between the treatment of Depression and AD. 'Autodock 4.2' was used for docking study. The free energy of binding (ΔG) values for 'levomilnacipran-SERT' interaction and 'levomilnacipran-BACE1' interaction were found to be -7.47 and -8.25 kcal/mol, respectively. Levomilnacipran was found to interact with S438, known to be the most important amino acid residue of serotonin binding site of SERT during 'levomilnacipran-SERT' interaction. In the case of 'levomilnacipran-BACE1' interaction, levomilnacipran interacted with two very crucial aspartic acid residues of BACE-1, namely, D32 and D228. These residues are accountable for the cleavage of amyloid precursor protein and the subsequent formation of amyloid β plaques in AD brain. Hence, Fetzima (levomilnacipran) might act as a potent dual inhibitor of SERT and BACE-1 and expected to form the basis of a future dual therapy against depression and AD. It is an established fact that development of AD is associated with Major Depressive Disorder. Therefore, the design of new BACE-1 inhibitors based on antidepressant drug scaffolds would be particularly beneficial.

Identification of myo-inositol hexakisphosphate (IP6) as a β-secretase 1 (BACE1) inhibitory molecule in rice grain extract and digest.

Science.gov (United States)

Abe, Takako K; Taniguchi, Masayuki

2014-01-01

Alzheimer's disease (AD) is widely considered to be caused by amyloid-β peptide (Aβ) accumulation in the brain. Aβ is excised from amyloid-β precursor protein through sequential cleavage by β-secretase 1 (BACE1) and γ-secretase. Thus, BACE1 inhibition could prevent Aβ accumulation. Here, we identified myo-inositol hexakisphosphate (IP6) as a BACE1 inhibitory molecule in rice grain extract and digest. The rice digest and IP6 significantly inhibited Aβ production in neuroblastoma cells without cytotoxicity. These results suggested that rice components, including IP6, may be promising starting materials for the development of potent and safe drugs and/or food to prevent AD.

Unveiling a novel transient druggable pocket in BACE-1 through molecular simulations: Conformational analysis and binding mode of multisite inhibitors

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Di Pietro, Ornella; Laughton, Charles A.

2017-01-01

The critical role of BACE-1 in the formation of neurotoxic ß-amyloid peptides in the brain makes it an attractive target for an efficacious treatment of Alzheimer’s disease. However, the development of clinically useful BACE-1 inhibitors has proven to be extremely challenging. In this study we examine the binding mode of a novel potent inhibitor (compound 1, with IC50 80 nM) designed by synergistic combination of two fragments—huprine and rhein—that individually are endowed with very low activity against BACE-1. Examination of crystal structures reveals no appropriate binding site large enough to accommodate 1. Therefore we have examined the conformational flexibility of BACE-1 through extended molecular dynamics simulations, paying attention to the highly flexible region shaped by loops 8–14, 154–169 and 307–318. The analysis of the protein dynamics, together with studies of pocket druggability, has allowed us to detect the transient formation of a secondary binding site, which contains Arg307 as a key residue for the interaction with small molecules, at the edge of the catalytic cleft. The formation of this druggable “floppy” pocket would enable the binding of multisite inhibitors targeting both catalytic and secondary sites. Molecular dynamics simulations of BACE-1 bound to huprine-rhein hybrid compounds support the feasibility of this hypothesis. The results provide a basis to explain the high inhibitory potency of the two enantiomeric forms of 1, together with the large dependence on the length of the oligomethylenic linker. Furthermore, the multisite hypothesis has allowed us to rationalize the inhibitory potency of a series of tacrine-chromene hybrid compounds, specifically regarding the apparent lack of sensitivity of the inhibition constant to the chemical modifications introduced in the chromene unit. Overall, these findings pave the way for the exploration of novel functionalities in the design of optimized BACE-1 multisite inhibitors

Encompassing receptor flexibility in virtual screening using ensemble docking-based hybrid QSAR: discovery of novel phytochemicals for BACE1 inhibition.

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Chakraborty, Sandipan; Ramachandran, Balaji; Basu, Soumalee

2014-10-01

Mimicking receptor flexibility during receptor-ligand binding is a challenging task in computational drug design since it is associated with a large increase in the conformational search space. In the present study, we have devised an in silico design strategy incorporating receptor flexibility in virtual screening to identify potential lead compounds as inhibitors for flexible proteins. We have considered BACE1 (β-secretase), a key target protease from a therapeutic perspective for Alzheimer's disease, as the highly flexible receptor. The protein undergoes significant conformational transitions from open to closed form upon ligand binding, which makes it a difficult target for inhibitor design. We have designed a hybrid structure-activity model containing both ligand based descriptors and energetic descriptors obtained from molecular docking based on a dataset of structurally diverse BACE1 inhibitors. An ensemble of receptor conformations have been used in the docking study, further improving the prediction ability of the model. The designed model that shows significant prediction ability judged by several statistical parameters has been used to screen an in house developed 3-D structural library of 731 phytochemicals. 24 highly potent, novel BACE1 inhibitors with predicted activity (Ki) ≤ 50 nM have been identified. Detailed analysis reveals pharmacophoric features of these novel inhibitors required to inhibit BACE1.

Molecular Docking and Dynamic Simulation of AZD3293 and Solanezumab Effects Against BACE1 to Treat Alzheimer's Disease

Directory of Open Access Journals (Sweden)

Mubashir Hassan

2018-06-01

Full Text Available The design of novel inhibitors to target BACE1 with reduced cytotoxicity effects is a promising approach to treat Alzheimer's disease (AD. Multiple clinical drugs and antibodies such as AZD3293 and Solanezumab are being tested to investigate their therapeutical potential against AD. The current study explores the binding pattern of AZD3293 and Solanezumab against their target proteins such as β-secretase (BACE1 and mid-region amyloid-beta (Aβ (PDBIDs: 2ZHV & 4XXD, respectively using molecular docking and dynamic simulation (MD approaches. The molecular docking results show that AZD3293 binds within the active region of BACE1 by forming hydrogen bonds against Asp32 and Lys107 with distances 2.95 and 2.68 Å, respectively. However, the heavy chain of Solanezumab interacts with Lys16 and Asp23 of amyloid beta having bond length 2.82, 2.78, and 3.00 Å, respectively. The dynamic cross correlations and normal mode analyses show that BACE1 depicted good residual correlated motions and fluctuations, as compared to Solanezumab. Using MD, the Root Mean Square Deviation and Fluctuation (RMSD/F graphs show that AZD3293 residual fluctuations and RMSD value (0.2 nm was much better compared to Solanezumab (0.7 nm. Moreover, the radius of gyration (Rg results also depicts the significance of AZD3293 docked complex compared to Solanezumab through residual compactness. Our comparative results show that AZD3293 is a better therapeutic agent for treating AD than Solanezumab.

Composite Fe - BaCe0.2Zr0.6Y0.2O2.9 Anodes for Proton Conductor Fuel Cells

DEFF Research Database (Denmark)

Lapina, Alberto; Chatzichristodoulou, Christodoulos; Holtappels, Peter

2014-01-01

Symmetrical cells with Fe - BaCe0.2Zr0.6Y0.2O2.9 composite electrodes are produced by screen printing and infiltration, using BaCe0.2Zr0.6Y0.2O2.9 as electrolyte. The electrochemical performance of the composite electrode is studied by impedance spectroscopy at 250–500◦C in dry and wet hydrogen/n...

Discovery of the 3-Imino-1,2,4-thiadiazinane 1,1-Dioxide Derivative Verubecestat (MK-8931)–A β-Site Amyloid Precursor Protein Cleaving Enzyme 1 Inhibitor for the Treatment of Alzheimer’s Disease

Energy Technology Data Exchange (ETDEWEB)

Scott, Jack D.; Li, Sarah W.; Brunskill, Andrew P.J.; Chen, Xia; Cox, Kathleen; Cumming, Jared N.; Forman, Mark; Gilbert, Eric J.; Hodgson, Robert A.; Hyde, Lynn A.; Jiang, Qin; Iserloh, Ulrich; Kazakevich, Irina; Kuvelkar, Reshma; Mei, Hong; Meredith, John; Misiaszek, Jeffrey; Orth, Peter; Rossiter, Lana M.; Slater, Meagan; Stone, Julie; Strickland, Corey O.; Voigt, Johannes H.; Wang, Ganfeng; Wang, Hongwu; Wu, Yusheng; Greenlee, William J.; Parker, Eric M.; Kennedy, Matthew E.; Stamford, Andrew W. (Merck)

2016-12-08

Verubecestat 3 (MK-8931), a diaryl amide-substituted 3-imino-1,2,4-thiadiazinane 1,1-dioxide derivative, is a high-affinity β-site amyloid precursor protein cleaving enzyme 1 (BACE1) inhibitor currently undergoing Phase 3 clinical evaluation for the treatment of mild to moderate and prodromal Alzheimer’s disease. Although not selective over the closely related aspartyl protease BACE2, verubecestat has high selectivity for BACE1 over other key aspartyl proteases, notably cathepsin D, and profoundly lowers CSF and brain Aβ levels in rats and nonhuman primates and CSF Aβ levels in humans. In this annotation, we describe the discovery of 3, including design, validation, and selected SAR around the novel iminothiadiazinane dioxide core as well as aspects of its preclinical and Phase 1 clinical characterization.

Evaluation of Small-Animal PET Outcome Measures to Detect Disease Modification Induced by BACE Inhibition in a Transgenic Mouse Model of Alzheimer Disease.

Science.gov (United States)

Deleye, Steven; Waldron, Ann-Marie; Verhaeghe, Jeroen; Bottelbergs, Astrid; Wyffels, Leonie; Van Broeck, Bianca; Langlois, Xavier; Schmidt, Mark; Stroobants, Sigrid; Staelens, Steven

2017-12-01

In this study, we investigated the effects of chronic administration of an inhibitor of the β-site amyloid precursor protein-cleaving enzyme 1 (BACE1) on Alzheimer-related pathology by multitracer PET imaging in transgenic APPPS1-21 (TG) mice. Methods: Wild-type (WT) and TG mice received vehicle or BACE inhibitor (60 mg/kg) starting at 7 wk of age. Outcome measures of brain metabolism, neuroinflammation, and amyloid-β pathology were obtained through small-animal PET imaging with 18 F-FDG, 18 F-peripheral benzodiazepine receptor ( 18 F-PBR), and 18 F-florbetapir ( 18 F-AV45), respectively. Baseline scans were acquired at 6-7 wk of age and follow-up scans at 4, 7, and 12 mo. 18 F-AV45 uptake was measured at 8 and 13 mo of age. After the final scans, histologic measures of amyloid-β (4G8), microglia (ionized calcium binding adaptor molecule 1), astrocytes (glial fibrillary acidic protein), and neuronal nuclei were performed. Results: TG mice demonstrated significant age-associated increases in 18 F-AV45 uptake. An effect of treatment was observed in the cortex ( P = 0.0014), hippocampus ( P = 0.0005), and thalamus ( P treatment, TG mice demonstrated significantly lower 18 F-FDG uptake than WT mice in the thalamus ( P = 0.0004) and hippocampus ( P = 0.0332). Neuronal nucleus staining was lower in both TG groups in the thalamus and cortex. 18 F-PBR111 detected a significant age-related increase in TG mice ( P treatment-induced reduction in activated microglia as demonstrated by histology. Conclusion: Although 18 F-FDG, 18 F-PBR111, and 18 F-AV45 all detected pathologic alterations between TG and WT mice, only 18 F-AV45 could detect an effect of BACE inhibitor treatment. However, changes in WT binding of 18 F-AV45 undermine the specificity of this effect. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

Thymoquinone-rich fraction nanoemulsion (TQRFNE) decreases Aβ40 and Aβ42 levels by modulating APP processing, up-regulating IDE and LRP1, and down-regulating BACE1 and RAGE in response to high fat/cholesterol diet-induced rats.

Science.gov (United States)

Ismail, Norsharina; Ismail, Maznah; Azmi, Nur Hanisah; Bakar, Muhammad Firdaus Abu; Yida, Zhang; Abdullah, Maizaton Atmadini; Basri, Hamidon

2017-11-01

Though the causes of Alzheimer's disease (AD) are yet to be understood, much evidence has suggested that excessive amyloid-β (Aβ) accumulation due to abnormal amyloid-β precursor protein (APP) processing and Aβ metabolism are crucial processes towards AD pathogenesis. Hence, approaches aiming at APP processing and Aβ metabolism are currently being actively pursued for the management of AD. Studies suggest that high cholesterol and a high fat diet have harmful effects on cognitive function and may instigate the commencement of AD pathogenesis. Despite the neuropharmacological attributes of black cumin seed (Nigella sativa) extracts and its main active compound, thymoquinone (TQ), limited records are available in relation to AD research. Nanoemulsion (NE) is exploited as drug delivery systems due to their capacity of solubilising non-polar active compounds and is widely examined for brain targeting. Herewith, the effects of thymoquinone-rich fraction nanoemulsion (TQRFNE), thymoquinone nanoemulsion (TQNE) and their counterparts' conventional emulsion in response to high fat/cholesterol diet (HFCD)-induced rats were investigated. Particularly, the Aβ generation; APP processing, β-secretase 1 (BACE1), γ-secretases of presenilin 1 (PSEN1) and presenilin 2 (PSEN2), Aβ degradation; insulin degrading enzyme (IDE), Aβ transportation; low density lipoprotein receptor-related protein 1 (LRP1) and receptor for advanced glycation end products (RAGE) were measured in brain tissues. TQRFNE reduced the brain Aβ fragment length 1-40 and 1-42 (Aβ40 and Aβ42) levels, which would attenuate the AD pathogenesis. This reduction could be due to the modulation of β- and γ-secretase enzyme activity, and the Aβ degradation and transportation in/out of the brain. The findings show the mechanistic actions of TQRFNE in response to high fat and high cholesterol diet associated to Aβ generation, degradation and transportation in the rat's brain tissue. Copyright © 2017 Elsevier

Investigation of naphthofuran moiety as potential dual inhibitor against BACE-1 and GSK-3β: molecular dynamics simulations, binding energy, and network analysis to identify first-in-class dual inhibitors against Alzheimer's disease.

Science.gov (United States)

Kumar, Akhil; Srivastava, Gaurava; Srivastava, Swati; Verma, Seema; Negi, Arvind S; Sharma, Ashok

2017-08-01

BACE-1 and GSK-3β are potential therapeutic drug targets for Alzheimer's disease. Recently, both the targets received attention for designing dual inhibitors for Alzheimer's disease. Until now, only two-scaffold triazinone and curcumin have been reported as BACE-1 and GSK-3β dual inhibitors. Docking, molecular dynamics, clustering, binding energy, and network analysis of triazinone derivatives with BACE-1 and GSK-3β was performed to get molecular insight into the first reported dual inhibitor. Further, we designed and evaluated a naphthofuran series for its ability to inhibit BACE-1 and GSK-3β with the computational approaches. Docking study of naphthofuran series showed a good binding affinity towards both the targets. Molecular dynamics, binding energy, and network analysis were performed to compare their binding with the targets and amino acids responsible for binding. Naphthofuran series derivatives showed good interaction within the active site residues of both of the targets. Hydrogen bond occupancy and binding energy suggested strong binding with the targets. Dual-inhibitor binding was mostly governed by the hydrophobic interactions for both of the targets. Per residue energy decomposition and network analysis identified the key residues involved in the binding and inhibiting BACE-1 and GSK-3β. The results indicated that naphthofuran series derivative 11 may be a promising first-in-class dual inhibitor against BACE-1 and GSK-3β. This naphthofuran series may be further explored to design better dual inhibitors. Graphical abstract Naphthofuran derivative as a dual inhibitor for BACE-1 and GSK-3β.

Creation of Novel Cores for β-Secretase (BACE-1) Inhibitors: A Multiparameter Lead Generation Strategy.

Science.gov (United States)

Viklund, Jenny; Kolmodin, Karin; Nordvall, Gunnar; Swahn, Britt-Marie; Svensson, Mats; Gravenfors, Ylva; Rahm, Fredrik

2014-04-10

In order to find optimal core structures as starting points for lead optimization, a multiparameter lead generation workflow was designed with the goal of finding BACE-1 inhibitors as a treatment for Alzheimer's disease. De novo design of core fragments was connected with three predictive in silico models addressing target affinity, permeability, and hERG activity, in order to guide synthesis. Taking advantage of an additive SAR, the prioritized cores were decorated with a few, well-characterized substituents from known BACE-1 inhibitors in order to allow for core-to-core comparisons. Prediction methods and analyses of how physicochemical properties of the core structures correlate to in vitro data are described. The syntheses and in vitro data of the test compounds are reported in a separate paper by Ginman et al. [J. Med. Chem. 2013, 56, 4181-4205]. The affinity predictions are described in detail by Roos et al. [J. Chem. Inf. 2014, DOI: 10.1021/ci400374z].

Process for preparing multilayer enzyme coating on a fiber

Science.gov (United States)

Kim, Jungbae [Richland, WA; Kwak, Ja Hun [Richland, WA; Grate, Jay W [West Richland, WA

2009-11-03

A process for preparing high stability, high activity biocatalytic materials is disclosed and processes for using the same. The process involves coating of a material or fiber with enzymes and enzyme aggregate providing a material or fiber with high biocatalytic activity and stability useful in heterogeneous environments. In one illustrative approach, enzyme "seeds" are covalently attached to polymer nanofibers followed by treatment with a reagent that crosslinks additional enzyme molecules to the seed enzymes forming enzyme aggregates thereby improving biocatalytic activity due to increased enzyme loading and enzyme stability. This approach creates a useful new biocatalytic immobilized enzyme system with potential applications in bioconversion, bioremediation, biosensors, and biofuel cells.

Enzymes as Biocatalysts for Lipid-based Bioproducts Processing

DEFF Research Database (Denmark)

Cheong, Ling-Zhi; Guo, Zheng; Fedosov, Sergey

2012-01-01

Bioproducts are materials, chemicals and energy derived from renewable biological resources such as agriculture, forestry, and biologically-derived wastes. To date, the use of enzymes as biocatalysts for lipid-based bioproducts processing has shown marked increase. This is mainly due to the fact...... that cost benefit derived from enzymatic processing such as enzyme specificity, higher product purity and lesser or none toxic waste disposal has surpassed the cost of biocatalysts itself. This chapter provided insights into distinct enzymes characteristics essential in industrial processing especially...... enzymes kinetics. Understanding of enzyme kinetics is important especially in designing efficient reaction set-ups including type of bioreactors, reaction conditions and reusability of biocatalysts to ensure efficient running cost. A brief review of state-of-the-art in industrial applications of enzymes...

Applications of Enzymes in Oil and Oilseed Processing

DEFF Research Database (Denmark)

Xu, Xuebing

Enzymes, through the last 20-30 years research and development, have been widely explored for the uses in oil and oilseed processing. Following the conventional processing technology from oilseeds, the oil can be produced through pressing or solvent extraction. The crude oil is then refined to meet...... edible requirements. The oil can be also modified to meet functional or even nutritional needs. In each of those steps, enzymes have been used in industry successfully. For the oil processing stage, enzymes have been used to destroy the cell structure so that makes the oil release easier, where...... conventionally high temperature conditioning or cooking is necessary. The good story in industry is the fish oil and olive oil processing. Good quality and higher oil yield have been achieved through the use of enzymes in the processing stages. For the refining stage, the use of enzymes for degumming has...

Enzymes- An Existing and Promising Tool of Food Processing Industry.

Science.gov (United States)

Ray, Lalitagauri; Pramanik, Sunita; Bera, Debabrata

2016-01-01

The enzyme catalyzed process technology has enormous potential in the food sectors as indicated by the recent patents studies. It is very well realized that the adaptation of the enzyme catalyzed process depends on the availability of enzyme in affordable prices. Enzymes may be used in different food sectors like dairy, fruits & vegetable processing, meat tenderization, fish processing, brewery and wine making, starch processing and many other. Commercially only a small number of enzymes are used because of several factors including instability of enzymes during processing and high cost. More and more enzymes for food technology are now derived from specially selected or genetically modified microorganisms grown in industrial scale fermenters. Enzymes with microbial source have commercial advantages of using microbial fermentation rather than animal and plant extraction to produce food enzymes. At present only a relatively small number of enzymes are used commercially in food processing. But the number is increasing day by day and field of application will be expanded more and more in near future. The purpose of this review is to describe the practical applications of enzymes in the field of food processing.

Combining NMR and X-ray crystallography in fragment-based drug discovery: discovery of highly potent and selective BACE-1 inhibitors.

Science.gov (United States)

Wyss, Daniel F; Wang, Yu-Sen; Eaton, Hugh L; Strickland, Corey; Voigt, Johannes H; Zhu, Zhaoning; Stamford, Andrew W

2012-01-01

Fragment-based drug discovery (FBDD) has become increasingly popular over the last decade. We review here how we have used highly structure-driven fragment-based approaches to complement more traditional lead discovery to tackle high priority targets and those struggling for leads. Combining biomolecular nuclear magnetic resonance (NMR), X-ray crystallography, and molecular modeling with structure-assisted chemistry and innovative biology as an integrated approach for FBDD can solve very difficult problems, as illustrated in this chapter. Here, a successful FBDD campaign is described that has allowed the development of a clinical candidate for BACE-1, a challenging CNS drug target. Crucial to this achievement were the initial identification of a ligand-efficient isothiourea fragment through target-based NMR screening and the determination of its X-ray crystal structure in complex with BACE-1, which revealed an extensive H-bond network with the two active site aspartate residues. This detailed 3D structural information then enabled the design and validation of novel, chemically stable and accessible heterocyclic acylguanidines as aspartic acid protease inhibitor cores. Structure-assisted fragment hit-to-lead optimization yielded iminoheterocyclic BACE-1 inhibitors that possess desirable molecular properties as potential therapeutic agents to test the amyloid hypothesis of Alzheimer's disease in a clinical setting.

Evaluation of thermostable enzymes for bioethanol processing

DEFF Research Database (Denmark)

Skovgaard, Pernille Anastasia

of fermentable sugars (glucose) as cellulose is tightly linked to hemicellulose and lignin. Lignocellulose is disrupted during pretreatment, but to degrade cellulose to single sugars, lignocellulolytic enzymes such as cellulases and hemicellulases are needed. Lignocellulolytic enzymes are costly...... for the ioethanol production, but the expenses can be reduced by using thermostable enzymes, which are known for their increased stability and inhibitor olerance. However, the advantage of using thermostable enzymes has not been studied thoroughly and more knowledge is needed for development of bioethanol processes....... Enzymes are added to the bioethanol process after pretreatment. For an efficient sugar and ethanol yield, the solids content of biomass is normally increased, which results in highly viscous slurries that are difficult to mix. Therefore, the first enzymatic challenge is to ensure rapid reduction...

Dose-dependent inhibition of BACE-1 by the monoterpenoid 2,3,4,4-tetramethyl-5-methylenecyclopent-2-enone in cellular and mouse models of Alzheimer's disease.

Science.gov (United States)

Videira, Rita; Castanheira, Pedro; Grãos, Mário; Resende, Rosa; Salgueiro, Lígia; Faro, Carlos; Cavaleiro, Carlos

2014-06-27

BACE-1 is an aspartic protease involved in the conversion of amyloid precursor protein (APP) to amyloid-β (Aβ) in vivo, which is one of the key steps in the development and progression of Alzheimer's disease. In a previous screening procedure for inhibitors of BACE-1 activity, the oil of Lavandula luisieri was identified as the most potent among several essential oils. The inhibitory effect of this essential oil on Aβ production was also demonstrated in a cellular assay. The composition of the volatile oil and the isolation of the compound responsible for the inhibitory activity were also reported. The present work focused on the characterization of the inhibition of BACE-1 by this active compound, a monoterpene necrodane ketone, 2,3,4,4-tetramethyl-5-methylenecyclopent-2-enone (1), with assessment of its Ki value and the type of inhibition. The dose-related effects of the compound were also evaluated using two different cell lines, with determinations of the respective EC50 values. The entire oil and the 2,3,4,4-tetramethyl-5-methylenecyclopent-2-enone (1) were tested on a triple transgenic mouse model of Alzheimer's disease. The overall results showed that compound 1 displayed a dose-dependent inhibition of BACE-1 in cellular and mouse models of Alzheimer's disease and is therefore capable of passing through cellular membranes and the blood-brain barrier.

Recent Advances in Marine Enzymes for Biotechnological Processes.

Science.gov (United States)

Lima, R N; Porto, A L M

In the last decade, new trends in the food and pharmaceutical industries have increased concern for the quality and safety of products. The use of biocatalytic processes using marine enzymes has become an important and useful natural product for biotechnological applications. Bioprocesses using biocatalysts like marine enzymes (fungi, bacteria, plants, animals, algae, etc.) offer hyperthermostability, salt tolerance, barophilicity, cold adaptability, chemoselectivity, regioselectivity, and stereoselectivity. Currently, enzymatic methods are used to produce a large variety of products that humans consume, and the specific nature of the enzymes including processing under mild pH and temperature conditions result in fewer unwanted side-effects and by-products. This offers high selectivity in industrial processes. The marine habitat has been become increasingly studied because it represents a huge source potential biocatalysts. Enzymes include oxidoreductases, hydrolases, transferases, isomerases, ligases, and lyases that can be used in food and pharmaceutical applications. Finally, recent advances in biotechnological processes using enzymes of marine organisms (bacterial, fungi, algal, and sponges) are described and also our work on marine organisms from South America, especially marine-derived fungi and bacteria involved in biotransformations and biodegradation of organic compounds. © 2016 Elsevier Inc. All rights reserved.

From BACE1 Inhibitor to Multifunctionality of Tryptoline and Tryptamine Triazole Derivatives for Alzheimer’s Disease

Directory of Open Access Journals (Sweden)

Jutamas Jiaranaikulwanitch

2012-07-01

Full Text Available Efforts to discover new drugs for Alzheimer’s disease emphasizing multiple targets was conducted seeking to inhibit amyloid oligomer formation and to prevent radical formation. The tryptoline and tryptamine cores of BACE1 inhibitors previously identified by virtual screening were modified in silico for additional modes of action. These core structures were readily linked to different side chains using 1,2,3-triazole rings as bridges by copper catalyzed azide-alkyne cycloaddition reactions. Three compounds among the sixteen designed compounds exerted multifunctional activities including β-secretase inhibitory action, anti-amyloid aggregation, metal chelating and antioxidant effects at micromolar levels. the neuroprotective effects of the multifunctional compounds 6h, 12c and 12h on Aβ_1-42 induced neuronal cell death at 1 μM were significantly greater than those of the potent single target compound, BACE1 inhibitor IV and were comparable to curcumin. The observed synergistic effect resulting from the reduction of the Aβ_1-42 neurotoxicity cascade substantiates the validity of our multifunctional strategy in drug discovery for Alzheimer’s disease.

Optimization of a novel enzyme treatment process for early-stage processing of sheepskins.

Science.gov (United States)

Lim, Y F; Bronlund, J E; Allsop, T F; Shilton, A N; Edmonds, R L

2010-01-01

An enzyme treatment process for early-stage processing of sheepskins has been previously reported by the Leather and Shoe Research Association of New Zealand (LASRA) as an alternative to current industry operations. The newly developed process had marked benefits over conventional processing in terms of a lowered energy usage (73%), processing time (47%) as well as water use (49%), but had been developed as a "proof of principle''. The objective of this work was to develop the process further to a stage ready for adoption by industry. Mass balancing was used to investigate potential modifications for the process based on the understanding developed from a detailed analysis of preliminary design trials. Results showed that a configuration utilising a 2 stage counter-current system for the washing stages and segregation and recycling of enzyme float prior to dilution in the neutralization stage was a significant improvement. Benefits over conventional processing include a reduction of residual TDS by 50% at the washing stages and 70% savings on water use overall. Benefits over the un-optimized LASRA process are reduction of solids in product after enzyme treatment and neutralization stages by 30%, additional water savings of 21%, as well as 10% savings of enzyme usage.

Targeted quantification of functional enzyme dynamics in environmental samples for microbially mediated biogeochemical processes: Targeted quantification of functional enzyme dynamics

Energy Technology Data Exchange (ETDEWEB)

Li, Minjing [School of Environmental Studies, China University of Geosciences, Wuhan 430074 People' s Republic of China; Gao, Yuqian [Pacific Northwest National Laboratory, Richland, WA 99354 USA; Qian, Wei-Jun [Pacific Northwest National Laboratory, Richland, WA 99354 USA; Shi, Liang [Pacific Northwest National Laboratory, Richland, WA 99354 USA; Liu, Yuanyuan [Pacific Northwest National Laboratory, Richland, WA 99354 USA; Nelson, William C. [Pacific Northwest National Laboratory, Richland, WA 99354 USA; Nicora, Carrie D. [Pacific Northwest National Laboratory, Richland, WA 99354 USA; Resch, Charles T. [Pacific Northwest National Laboratory, Richland, WA 99354 USA; Thompson, Christopher [Pacific Northwest National Laboratory, Richland, WA 99354 USA; Yan, Sen [School of Environmental Studies, China University of Geosciences, Wuhan 430074 People' s Republic of China; Fredrickson, James K. [Pacific Northwest National Laboratory, Richland, WA 99354 USA; Zachara, John M. [Pacific Northwest National Laboratory, Richland, WA 99354 USA; Liu, Chongxuan [Pacific Northwest National Laboratory, Richland, WA 99354 USA; School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055 People' s Republic of China

2017-07-13

Microbially mediated biogeochemical processes are catalyzed by enzymes that control the transformation of carbon, nitrogen, and other elements in environment. The dynamic linkage between enzymes and biogeochemical species transformation has, however, rarely been investigated because of the lack of analytical approaches to efficiently and reliably quantify enzymes and their dynamics in soils and sediments. Herein, we developed a signature peptide-based technique for sensitively quantifying dissimilatory and assimilatory enzymes using nitrate-reducing enzymes in a hyporheic zone sediment as an example. Moreover, the measured changes in enzyme concentration were found to correlate with the nitrate reduction rate in a way different from that inferred from biogeochemical models based on biomass or functional genes as surrogates for functional enzymes. This phenomenon has important implications for understanding and modeling the dynamics of microbial community functions and biogeochemical processes in environments. Our results also demonstrate the importance of enzyme quantification for the identification and interrogation of those biogeochemical processes with low metabolite concentrations as a result of faster enzyme-catalyzed consumption of metabolites than their production. The dynamic enzyme behaviors provide a basis for the development of enzyme-based models to describe the relationship between the microbial community and biogeochemical processes.

From BACE1 Inhibitor to Multifunctionality of Tryptoline and Tryptamine Triazole Derivatives for Alzheimer’s Disease

OpenAIRE

Jiaranaikulwanitch, Jutamas; Govitrapong, Piyarat; Fokin, Valery V.; Vajragupta, Opa

2012-01-01

Efforts to discover new drugs for Alzheimer’s disease emphasizing multiple targets was conducted seeking to inhibit amyloid oligomer formation and to prevent radical formation. The tryptoline and tryptamine cores of BACE1 inhibitors previously identified by virtual screening were modified in silico for additional modes of action. These core structures were readily linked to different side chains using 1,2,3-triazole rings as bridges by copper catalyzed azide-alkyne cycloa...

Application of residual polysaccharide-degrading enzymes in dried shiitake mushrooms as an enzyme preparation in food processing.

Science.gov (United States)

Tatsumi, E; Konishi, Y; Tsujiyama, S

2016-11-01

To examine the activities of residual enzymes in dried shiitake mushrooms, which are a traditional foodstuff in Japanese cuisine, for possible applications in food processing. Polysaccharide-degrading enzymes remained intact in dried shiitake mushrooms and the activities of amylase, β-glucosidase and pectinase were high. A potato digestion was tested using dried shiitake powder. The enzymes reacted with potato tuber specimens to solubilize sugars even under a heterogeneous solid-state condition and that their reaction modes were different at 38 and 50 °C. Dried shiitake mushrooms have a potential use in food processing as an enzyme preparation.

First demonstration of cerebrospinal fluid and plasma A beta lowering with oral administration of a beta-site amyloid precursor protein-cleaving enzyme 1 inhibitor in nonhuman primates.

Science.gov (United States)

Sankaranarayanan, Sethu; Holahan, Marie A; Colussi, Dennis; Crouthamel, Ming-Chih; Devanarayan, Viswanath; Ellis, Joan; Espeseth, Amy; Gates, Adam T; Graham, Samuel L; Gregro, Allison R; Hazuda, Daria; Hochman, Jerome H; Holloway, Katharine; Jin, Lixia; Kahana, Jason; Lai, Ming-tain; Lineberger, Janet; McGaughey, Georgia; Moore, Keith P; Nantermet, Philippe; Pietrak, Beth; Price, Eric A; Rajapakse, Hemaka; Stauffer, Shaun; Steinbeiser, Melissa A; Seabrook, Guy; Selnick, Harold G; Shi, Xiao-Ping; Stanton, Matthew G; Swestock, John; Tugusheva, Katherine; Tyler, Keala X; Vacca, Joseph P; Wong, Jacky; Wu, Guoxin; Xu, Min; Cook, Jacquelynn J; Simon, Adam J

2009-01-01

beta-Site amyloid precursor protein (APP)-cleaving enzyme (BACE) 1 cleavage of amyloid precursor protein is an essential step in the generation of the potentially neurotoxic and amyloidogenic A beta 42 peptides in Alzheimer's disease. Although previous mouse studies have shown brain A beta lowering after BACE1 inhibition, extension of such studies to nonhuman primates or man was precluded by poor potency, brain penetration, and pharmacokinetics of available inhibitors. In this study, a novel tertiary carbinamine BACE1 inhibitor, tertiary carbinamine (TC)-1, was assessed in a unique cisterna magna ported rhesus monkey model, where the temporal dynamics of A beta in cerebrospinal fluid (CSF) and plasma could be evaluated. TC-1, a potent inhibitor (IC(50) approximately 0.4 nM), has excellent passive membrane permeability, low susceptibility to P-glycoprotein transport, and lowered brain A beta levels in a mouse model. Intravenous infusion of TC-1 led to a significant but transient lowering of CSF and plasma A beta levels in conscious rhesus monkeys because it underwent CYP3A4-mediated metabolism. Oral codosing of TC-1 with ritonavir, a potent CYP3A4 inhibitor, twice daily over 3.5 days in rhesus monkeys led to sustained plasma TC-1 exposure and a significant and sustained reduction in CSF sAPP beta, A beta 40, A beta 42, and plasma A beta 40 levels. CSF A beta 42 lowering showed an EC(50) of approximately 20 nM with respect to the CSF [TC-1] levels, demonstrating excellent concordance with its potency in a cell-based assay. These results demonstrate the first in vivo proof of concept of CSF A beta lowering after oral administration of a BACE1 inhibitor in a nonhuman primate.

Cleavage of ST6Gal I by Radiation-Induced BACE1 Inhibits Golgi-Anchored ST6Gal I-Mediated Sialylation of Integrin β1 and Migration in Colon Cancer Cells

International Nuclear Information System (INIS)

Lee, Minyoung; Park, Jung-Jin; Ko, Young-Gyu; Lee, Yun-Sil

2012-01-01

Previously, we found that β-galactoside α2,6-sialyltransferase (ST6Gal I), an enzyme that adds sialic acids to N-linked oligosaccharides of glycoproteins and is frequently overexpressed in cancer cells, is up-regulated by ionizing radiation (IR) and cleaved to a form possessing catalytic activity comparable to that of the Golgi-localized enzyme. Moreover, this soluble form is secreted into the culture media. Induction of ST6Gal I significantly increased the migration of colon cancer cells via sialylation of integrin β1. Here, we further investigated the mechanisms underlying ST6Gal I cleavage, solubilization and release from cells, and addressed its functions, focusing primarily on cancer cell migration. We performed immunoblotting and lectin affinity assay to analyze the expression of ST6 Gal I and level of sialylated integrin β1. After ionizing radiation, migration of cells was measured by in vitro migration assay. α2, 6 sialylation level of cell surface was analyzed by flow cytometry. Cell culture media were concentrated and then analyzed for soluble ST6Gal I levels using an α2, 6 sialyltransferase sandwich ELISA. We found that ST6Gal I was cleaved by BACE1 (β-site amyloid precursor protein-cleaving enzyme), which was specifically overexpressed in response to IR. The soluble form of ST6Gal I, which also has sialyltransferase enzymatic activity, was cleaved from the Golgi membrane and then released into the culture media. Both non-cleaved and cleaved forms of ST6Gal I significantly increased colon cancer cell migration in a sialylation-dependent manner. The pro-migratory effect of the non-cleaved form of ST6Gal I was dependent on integrin β1 sialylation, whereas that of the cleaved form of ST6Gal I was not, suggesting that other intracellular sialylated molecules apart from cell surface molecules such as integrin β1 might be involved in mediating the pro-migratory effects of the soluble form of ST6Gal I. Moreover, production of soluble form ST6Gal I by

Anti-Alzheimer's disease activity of compounds from the root bark of Morus alba L.

Science.gov (United States)

Kuk, Eun Bi; Jo, A Ra; Oh, Seo In; Sohn, Hee Sook; Seong, Su Hui; Roy, Anupom; Choi, Jae Sue; Jung, Hyun Ah

2017-03-01

The inhibition of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and β-site amyloid precursor protein cleaving enzyme 1 (BACE1) plays important roles in prevention and treatment of Alzheimer's disease (AD). Among the individual parts of Morus alba L. including root bark, branches, leaves, and fruits, the root bark showed the most potent enzyme inhibitory activities. Therefore, the aim of this study was to evaluate the anti-AD activity of the M. alba root bark and its isolate compounds, including mulberrofuran G (1), albanol B (2), and kuwanon G (3) via inhibition of AChE, BChE, and BACE1. Compounds 1 and 2 showed strong AChE- and BChE-inhibitory activities; 1-3 showed significant BACE1 inhibitory activity. Based on the kinetic study with AChE and BChE, 2 and 3 showed noncompetitive-type inhibition; 1 showed mixed-type inhibition. Moreover, 1-3 showed mixed-type inhibition against BACE1. The molecular docking simulations of 1-3 demonstrated negative binding energies, indicating a high affinity to AChE and BACE1. The hydroxyl group of 1-3 formed hydrogen bond with the amino acid residues located at AChE and BACE1. Consequently, these results indicate that the root bark of M. alba and its active compounds might be promising candidates for preventive and therapeutic agents for AD.

Enzyme clustering accelerates processing of intermediates through metabolic channeling

Science.gov (United States)

Castellana, Michele; Wilson, Maxwell Z.; Xu, Yifan; Joshi, Preeti; Cristea, Ileana M.; Rabinowitz, Joshua D.; Gitai, Zemer; Wingreen, Ned S.

2015-01-01

We present a quantitative model to demonstrate that coclustering multiple enzymes into compact agglomerates accelerates the processing of intermediates, yielding the same efficiency benefits as direct channeling, a well-known mechanism in which enzymes are funneled between enzyme active sites through a physical tunnel. The model predicts the separation and size of coclusters that maximize metabolic efficiency, and this prediction is in agreement with previously reported spacings between coclusters in mammalian cells. For direct validation, we study a metabolic branch point in Escherichia coli and experimentally confirm the model prediction that enzyme agglomerates can accelerate the processing of a shared intermediate by one branch, and thus regulate steady-state flux division. Our studies establish a quantitative framework to understand coclustering-mediated metabolic channeling and its application to both efficiency improvement and metabolic regulation. PMID:25262299

Synthesis, Sintering, and Electrical Properties of BaCe0.9−xZrxY0.1O3−δ

DEFF Research Database (Denmark)

Ricote, S.; Caboche, G.; Estournes, C.

2008-01-01

BaCe0.9-xZrxY0.1O3-delta powders were synthesized by a solid-state reaction. Different contents of cerium and zirconium were studied. Pellets were sintered using either conventional sintering in air at 1700 degrees C or the Spark Plasma Sintering (SPS) technique. The density of the samples sintered...

Bilingual Academic and Career Education Services for Hispanic High School Students (Project BACES). Final Evaluation Report, 1992-93. OER Report.

Science.gov (United States)

Clarke, Candice

This report presents an evaluation of the Bilingual Academic and Career Education Services for Hispanic High School Students (Project BACES), an Elementary and Secondary Education Act Title VII-funded project in its third year of operation at DeWitt Clinton High School in the Bronx and George Washington High School in Manhattan. The project served…

Genetic Deletion of the Clathrin Adaptor GGA3 Reduces Anxiety and Alters GABAergic Transmission.

Directory of Open Access Journals (Sweden)

Kendall R Walker

Full Text Available Golgi-localized γ-ear-containing ARF binding protein 3 (GGA3 is a monomeric clathrin adaptor that has been shown to regulate the trafficking of the Beta-site APP-cleaving enzyme (BACE1, which is required for production of the Alzheimer's disease (AD-associated amyloid βpeptide. Our previous studies have shown that BACE1 is degraded via the lysosomal pathway and that depletion of GGA3 results in increased BACE1 levels and activity owing to impaired lysosomal trafficking and degradation. We further demonstrated the role of GGA3 in the regulation of BACE1 in vivo by showing that BACE1 levels are increased in the brain of GGA3 null mice. We report here that GGA3 deletion results in novelty-induced hyperactivity and decreased anxiety-like behaviors. Given the pivotal role of GABAergic transmission in the regulation of anxiety-like behaviors, we performed electrophysiological recordings in hippocampal slices and found increased phasic and decreased tonic inhibition in the dentate gyrus granule cells (DGGC. Moreover, we found that the number of inhibitory synapses is increased in the dentate gyrus of GGA3 null mice in further support of the electrophysiological data. Thus, the increased GABAergic transmission is a leading candidate mechanism underlying the reduced anxiety-like behaviors observed in GGA3 null mice. All together these findings suggest that GGA3 plays a key role in GABAergic transmission. Since BACE1 levels are elevated in the brain of GGA3 null mice, it is possible that at least some of these phenotypes are a consequence of increased processing of BACE1 substrates.

Genetic Deletion of the Clathrin Adaptor GGA3 Reduces Anxiety and Alters GABAergic Transmission.

Science.gov (United States)

Walker, Kendall R; Modgil, Amit; Albrecht, David; Lomoio, Selene; Haydon, Philip G; Moss, Stephen J; Tesco, Giuseppina

2016-01-01

Golgi-localized γ-ear-containing ARF binding protein 3 (GGA3) is a monomeric clathrin adaptor that has been shown to regulate the trafficking of the Beta-site APP-cleaving enzyme (BACE1), which is required for production of the Alzheimer's disease (AD)-associated amyloid βpeptide. Our previous studies have shown that BACE1 is degraded via the lysosomal pathway and that depletion of GGA3 results in increased BACE1 levels and activity owing to impaired lysosomal trafficking and degradation. We further demonstrated the role of GGA3 in the regulation of BACE1 in vivo by showing that BACE1 levels are increased in the brain of GGA3 null mice. We report here that GGA3 deletion results in novelty-induced hyperactivity and decreased anxiety-like behaviors. Given the pivotal role of GABAergic transmission in the regulation of anxiety-like behaviors, we performed electrophysiological recordings in hippocampal slices and found increased phasic and decreased tonic inhibition in the dentate gyrus granule cells (DGGC). Moreover, we found that the number of inhibitory synapses is increased in the dentate gyrus of GGA3 null mice in further support of the electrophysiological data. Thus, the increased GABAergic transmission is a leading candidate mechanism underlying the reduced anxiety-like behaviors observed in GGA3 null mice. All together these findings suggest that GGA3 plays a key role in GABAergic transmission. Since BACE1 levels are elevated in the brain of GGA3 null mice, it is possible that at least some of these phenotypes are a consequence of increased processing of BACE1 substrates.

Protein engineering of enzymes for process applications

DEFF Research Database (Denmark)

Woodley, John M

2013-01-01

opportunities will be targeted on modification to enable process application. This article discusses the challenges involved in enzyme modification focused on process requirements, such as the need to fulfill reaction thermodynamics, specific activity under the required conditions, kinetics at required...... concentrations, and stability. Finally, future research directions are discussed, including the integration of biocatalysis with neighboring chemical steps....

Profile of yttrium segregation in BaCe0,9Y0,1O3-δ as function of sintering temperature

International Nuclear Information System (INIS)

Hosken, C.M.; Souza, D.P.F. de

2010-01-01

Researches on solid oxide fuel cells indicate barium cerate perovskite as a very attractive material for using as electrolyte due to its high protonic conductivity. The objective of this work is investigate the yttrium segregation during sintering of BaCe 0,9 Y 0,1 O 3-δ doped with Zn O as a sintering aid. The powders were prepared by citrate process. Powders were isostatic pressed into pellets and sintered in air at 1200, 1275, 1325 and 1400 deg C. The samples were characterized by scanning electron microscopy, X-ray diffraction and impedance spectroscopy. Secondary phase containing Yttrium and Cerium was detected as sintering temperature increased. Increase of the lattice parameter and activation energy for electrical conductivity were also detected on samples sintered at 1400 deg C. (author)

β-Secretases, Alzheimer’s Disease, and Down Syndrome

Directory of Open Access Journals (Sweden)

Robin L. Webb

2012-01-01

Full Text Available Individuals with Down Syndrome (DS, or trisomy 21, develop Alzheimer’s disease (AD pathology by approximately 40 years of age. Chromosome 21 harbors several genes implicated in AD, including the amyloid precursor protein and one homologue of the β-site APP cleaving enzyme, BACE2. Processing of the amyloid precursor protein by β-secretase (BACE is the rate-limiting step in the production of the pathogenic Aβ peptide. Increased amounts of APP in the DS brain result in increased amounts of Aβ and extracellular plaque formation beginning early in life. BACE dysregulation potentially represents an overlapping biological mechanism with sporadic AD and a common therapeutic target. As the lifespan for those with DS continues to increase, age-related concerns such as obesity, depression, and AD are of growing concern. The ability to prevent or delay the progression of neurodegenerative diseases will promote healthy aging and improve quality of life for those with DS.

Increased CSF-BACE 1 Activity Is Associated with ApoE-[Epsilon]4 Genotype in Subjects with Mild Cognitive Impairment and Alzheimer's Disease

Science.gov (United States)

Ewers, Michael; Zhong, Zhenyu; Burger, Katharina; Wallin, Anders; Blennow, Kaj; Teipel, Stefan J.; Shen, Yong; Hampel, Harald

2008-01-01

The Apolipoprotein (ApoE) [epsilon]4 allele is a major genetic risk factor of Alzheimer's disease, and may affect the production of amyloid beta (A[beta][subscript 1-42]). Recently, we have shown that [beta]-secretase (BACE 1) activity can be reliably detected within the brain and human CSF. Here, we have examined an association between the ApoE…

Seamless integration of dose-response screening and flow chemistry: efficient generation of structure-activity relationship data of β-secretase (BACE1) inhibitors.

Science.gov (United States)

Werner, Michael; Kuratli, Christoph; Martin, Rainer E; Hochstrasser, Remo; Wechsler, David; Enderle, Thilo; Alanine, Alexander I; Vogel, Horst

2014-02-03

Drug discovery is a multifaceted endeavor encompassing as its core element the generation of structure-activity relationship (SAR) data by repeated chemical synthesis and biological testing of tailored molecules. Herein, we report on the development of a flow-based biochemical assay and its seamless integration into a fully automated system comprising flow chemical synthesis, purification and in-line quantification of compound concentration. This novel synthesis-screening platform enables to obtain SAR data on b-secretase (BACE1) inhibitors at an unprecedented cycle time of only 1 h instead of several days. Full integration and automation of industrial processes have always led to productivity gains and cost reductions, and this work demonstrates how applying these concepts to SAR generation may lead to a more efficient drug discovery process. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Population PKPD modeling of BACE1 inhibitor-induced reduction in Aβ levels in vivo and correlation to in vitro potency in primary cortical neurons from mouse and guinea pig.

Science.gov (United States)

Janson, Juliette; Eketjäll, Susanna; Tunblad, Karin; Jeppsson, Fredrik; Von Berg, Stefan; Niva, Camilla; Radesäter, Ann-Cathrin; Fälting, Johanna; Visser, Sandra A G

2014-03-01

The aims were to quantify the in vivo time-course between the oral dose, the plasma and brain exposure and the inhibitory effect on Amyloid β (Aβ) in brain and cerebrospinal fluid, and to establish the correlation between in vitro and in vivo potency of novel β-secretase (BACE1) inhibitors. BACE1-mediated inhibition of Aβ was quantified in in vivo dose- and/or time-response studies and in vitro in SH-SY5Y cells, N2A cells, and primary cortical neurons (PCN). An indirect response model with inhibition on Aβ production rate was used to estimate unbound in vivo IC 50 in a population pharmacokinetic-pharmacodynamic modeling approach. Estimated in vivo inhibitory potencies varied between 1 and 1,000 nM. The turnover half-life of Aβ40 in brain was predicted to be 0.5 h in mouse and 1 h in guinea pig. An excellent correlation between PCN and in vivo potency was observed. Moreover, a strong correlation in potency was found between human SH-SY5Y cells and mouse PCN, being 4.5-fold larger in SH-SY5Y cells. The strong in vivo-in vitro correlation increased the confidence in using human cell lines for screening and optimization of BACE1 inhibitors. This can optimize the design and reduce the number of preclinical in vivo effect studies.

Discovery and X-ray crystallographic analysis of a spiropiperidine iminohydantoin inhibitor of beta-secretase.

Science.gov (United States)

Barrow, James C; Stauffer, Shaun R; Rittle, Kenneth E; Ngo, Phung L; Yang, ZhiQiang; Selnick, Harold G; Graham, Samuel L; Munshi, Sanjeev; McGaughey, Georgia B; Holloway, M Katharine; Simon, Adam J; Price, Eric A; Sankaranarayanan, Sethu; Colussi, Dennis; Tugusheva, Katherine; Lai, Ming-Tain; Espeseth, Amy S; Xu, Min; Huang, Qian; Wolfe, Abigail; Pietrak, Beth; Zuck, Paul; Levorse, Dorothy A; Hazuda, Daria; Vacca, Joseph P

2008-10-23

A high-throughput screen at 100 microM inhibitor concentration for the BACE-1 enzyme revealed a novel spiropiperidine iminohydantoin aspartyl protease inhibitor template. An X-ray cocrystal structure with BACE-1 revealed a novel mode of binding whereby the inhibitor interacts with the catalytic aspartates via bridging water molecules. Using the crystal structure as a guide, potent compounds with good brain penetration were designed.

Enzyme technology for precision functional food ingredient processes

DEFF Research Database (Denmark)

Meyer, Anne S.

2010-01-01

modification of potato starch processing residues. Such targeted enzyme-catalyzed reactions provide new invention opportunities for designing functional foods with significant health benefits. The provision of well-defined naturally structured compounds can, moreover, assist in obtaining the much...

Profound Understanding of Effect of Transition Metal Dopant, Sintering Temperature, and pO2 on the Electrical and Optical Properties of Proton Conducting BaCe0.9Sm0.1O3-δ.

Science.gov (United States)

Handal, Hala T; Hassan, Azfar; Leeson, Ryan; Eloui, Sherif M; Fitzpatrick, Martin; Thangadurai, Venkataraman

2016-01-19

This study reports the effect of transition metal (TM) substitution on the electrical and optical properties of BaCe0.9Sm0.1O3-δ (BCS). Concentrations of 5-10 mol % of each of Fe and Co have been doped for the B-site of BCS by citric acid autocombustion method. Powder X-ray diffraction has revealed the formation of an orthorhombic perovskite-type structure. FTIR confirmed a distortion in the lattice upon TM-doping in BCS. Scanning electron microscopy (SEM) images of 1400 °C sintered samples have manifested a higher densification in BaCe0.8Sm0.1Co0.1O3-δ (BCSC10) with a grain size ∼11 μm compared to the parent compound BCS (∼2 μm). Thermogravimetric (TG) analysis showed a water uptake in case of BaCe0.85Sm0.1Co0.05O3-δ (BCSC5), while BaCe0.85Sm0.1Fe0.05O3-δ (BCSF5) did not show a noteworthy uptake of water. TG has also proved that the incorporation of Fe and Co in BCS did not improve the chemical stability in CO2 at elevated temperature. The band gap estimated using Kubelka-Munk model based on the diffuse reflectance data was found to be the lowest for BCSC5 (2.47 eV). However, it increases upon lowering oxygen partial pressure (pO2), which was interpreted by a band structure modifications. Among the samples investigated, BCSC10 sintered at 1400 °C showed the highest electrical conductivity of 0.02 S cm(-1) in air at 600 °C, while its proton mobility appears to be negligible under the investigated humidity atmosphere.

Quality-related enzymes in plant-based products: effects of novel food processing technologies part 2: pulsed electric field processing.

Science.gov (United States)

Terefe, Netsanet Shiferaw; Buckow, Roman; Versteeg, Cornelis

2015-01-01

Pulsed electric field (PEF) processing is an effective technique for the preservation of pumpable food products as it inactivates vegetative microbial cells at ambient to moderate temperature without significantly affecting the nutritional and sensorial quality of the product. However, conflicting views are expressed about the effect of PEF on enzymes. In this review, which is part 2 of a series of reviews dealing with the effectiveness of novel food preservation technologies for controlling enzymes, the scientific literature over the last decade on the effect of PEF on plant enzymes is critically reviewed to shed more light on the issue. The existing evidence indicates that PEF can result in substantial inactivation of most enzymes, although a much more intense process is required compared to microbial inactivation. Depending on the processing condition and the origin of the enzyme, up to 97% inactivation of pectin methylesterase, polyphenol oxidase, and peroxidase as well as no inactivation have been reported following PEF treatment. Both electrochemical effects and Ohmic heating appear to contribute to the observed inactivation, although the relative contribution depends on a number of factors including the origin of the enzyme, the design of the PEF treatment chamber, the processing condition, and the composition of the medium.

Thermodynamic and kinetic characterization of hydroxyethylamine β-secretase-1 inhibitors

Energy Technology Data Exchange (ETDEWEB)

Mondal, Kalyani; Regnstrom, Karin; Morishige, Winse; Barbour, Robin; Probst, Gary; Xu, Ying-Zi; Artis, Dean R.; Yao, Nanhua; Beroza, Paul; Bova, Michael P., E-mail: mpbova2001@yahoo.com

2013-11-15

Highlights: •Kinetic and thermodynamic characterization of 10 hydroxyethylamine BACE-1 inhibitors. •Equilibrium binding of inhibitors was enthalpy driven for BACE-1. •Negative entropy of binding was observed towards BACE-1, but not Cathepsin-D. •Structural analysis demonstrates ligand binding induces a major conformational change. •Structural analysis and SPR analysis corroborate induced fit and negative entropy of binding. -- Abstract: Alzheimer’s disease (AD) is a devastating neurodegenerative disease affecting millions of people. β-Secretase-1 (BACE-1), an enzyme involved in the processing of the amyloid precursor protein (APP) to form Aβ, is a well validated target for AD. Herein, the authors characterize 10 randomly selected hydroxyethylamine (HEA) BACE-1 inhibitors in terms of their association and dissociation rate constants and thermodynamics of binding using surface plasmon resonance (SPR). Rate constants of association (k{sub a}) measured at 25 °C ranged from a low of 2.42 × 10{sup 4} M{sup −1} s{sup −1} to the highest value of 8.3 × 10{sup 5} M{sup −1} s{sup −1}. Rate constants of dissociation (k{sub d}) ranged from 1.09 × 10{sup −4} s{sup −1} (corresponding to a residence time of close to three hours), to the fastest of 0.028 s{sup −1}. Three compounds were selected for further thermodynamic analysis where it was shown that equilibrium binding was enthalpy driven while unfavorable entropy of binding was observed. Structural analysis revealed that upon ligand binding, the BACE-1flap folds down over the bound ligand causing an induced fit. The maximal difference between alpha carbon positions in the open and closed conformations of the flap was over 5 Å. Thus the negative entropy of binding determined using SPR analysis was consistent with an induced fit observed by structural analysis.

Water vapour solubility and conductivity study of the proton conductor BaCe(0.9 − x)ZrxY0.1O(3 − δ)

DEFF Research Database (Denmark)

Ricote, Sandrine; Bonanos, Nikolaos; Caboche, G:

2009-01-01

The perovskite BaCe(0.9 − x)ZrxY0.1O(3 − δ) has been prepared by solid state reaction at 1400 °C and conventional sintering at 1700 °C. Water uptake experiments performed between 400 and 600 °C, at a water vapour pressure of 0.02 atm, provide data on the concentration of protons incorporated in t...

Proglobulin processing enzyme in vacuoles isolated from developing pumpkin cotyledons

International Nuclear Information System (INIS)

Hara-Nishimura, I.; Nishimura, M.

1987-01-01

The enzymic conversion of proglobulin to globulin catalyzed by the extracts of vacuoles isolated from developing pumpkin (Cucurbita sp. cv Kurokawa Amakuri Nankin) cotyledons was investigated. The endoplasmic reticulum fraction isolated from the developing cotyledons pulse-labeled with [ 35 S]methionine was shown to contain mainly the radiolabeled proglobulin, which was used as a substrate for assaying the proteolytic processing in vitro. The vacuolar extracts catalyzed the proteolytic processing of the proglobulin molecule to produce globulin containing two kinds of polypeptide chains, γ and δ. The pH optimum for the vacuole-mediated conversion was at pH 5.0. The proteolytic processing of proglobulin by the vacuolar extracts was inhibited in the presence of various thiol reagents, e.g. p-chloromercuribenzoate, N-ethylmaleimide, iodoacetic acid, Hg 2+ , and Cu 2+ , but not phenylmethylsulfonyl fluoride, EDTA, o-phenanthroline, leupeptin, antipain, pepstatin, chymostatin, or pumpkin trypsin inhibitor, and was activated in the presence of dithiothreitol and cysteine, indicating that the processing enzyme is a thiol protease. The suborganellar fractionation of the vacuoles showed that the processing activity was localized in the matrix fraction, but not in the membrane or crystalloid fractions. During the seed development, the enzyme was shown to increase, exhibiting the maximal activity at the late developmental stage. The matrix fraction of the protein bodies isolated from the dry castor bean (Ricinus communis) exhibited the processing activity toward the pumpkin proglobulin molecules in the same manner as that by the matrix fraction of pumpkin vacuoles

Structural and conductivity study of the proton conductor BaCe(0.9−x)ZrxY0.1O(3−δ) at intermediate temperatures

DEFF Research Database (Denmark)

Ricote, Sandrine; Bonanos, Nikolaos; Marco de Lucas, M.C.

2009-01-01

The perovskite BaCe(0.9−x)ZrxY0.1O(3−δ) is prepared by solid-state reaction at 1400 °C and sintering at 1700 °C. It is characterised using X-ray diffraction, Raman spectroscopy and electrical measurements. A distortion from the cubic structure at room temperature is noticeable in the Raman spectr...

Nedd8 processing enzymes in Schizosaccharomyces pombe

DEFF Research Database (Denmark)

O'Donoghue, Jean; Bech-Otschir, Dawadschargal; Larsen, Ida

2013-01-01

Conjugation of the ubiquitin-like modifier Nedd8 to cullins is critical for the function of SCF-type ubiquitin ligases and thus facilitates ubiquitin conjugation and ultimately degradation of SCF substrates, including several cell cycle regulators. Like ubiquitin, Nedd8 is produced as a precursor...... that must first be processed before it becomes active. In Saccharomyces cerevisiae this is carried out exclusively by the enzyme Yuh1....

Kinetics and molecular docking studies of loganin, morroniside and 7-O-galloyl-D-sedoheptulose derived from Corni fructus as cholinesterase and β-secretase 1 inhibitors.

Science.gov (United States)

Bhakta, Himanshu Kumar; Park, Chan Hum; Yokozawa, Takako; Min, Byung-Sun; Jung, Hyun Ah; Choi, Jae Sue

2016-06-01

We evaluated the major active components isolated from Corni Fructus: loganin, morroniside, and 7-O-galloyl-D-sedoheptulose as inhibitors of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and β-site amyloid precursor protein (APP) cleaving enzyme 1 (BACE1) for use in Alzheimer's disease treatment. These compounds exhibited predominant cholinesterase (ChEs) inhibitory effects with IC50 values of 0.33, 3.95, and 10.50 ± 1.16 µM, respectively, for AChE, and 33.02, 37.78, and 87.94 ± 4.66 µM, respectively, for BChE. Kinetics studies revealed that loganin and 7-O-galloyl-D-sedoheptulose inhibited AChE with characteristics typical of mixed inhibitors, while morroniside was found to be a noncompetitive inhibitor against AChE and also exerted mixed BChE inhibitory activities. For BACE1, loganin showed noncompetitive type inhibitory effects, while morroniside and 7-O-galloyl-D-sedoheptulose were found to be mixed inhibitors. Furthermore, these compounds exhibited dose-dependent inhibitory activity with ONOO(-)-mediated protein tyrosine nitration. Molecular docking simulation of these compounds demonstrated negative binding energies for ChEs, and BACE1, indicating high affinity and tighter binding capacity for the active site of the enzyme. Loganin was the most potent inhibitor against both ChEs and BACE1. The data suggest that these compounds together can act as a triple inhibitor of AChE, BChE, and BACE1, providing a preventive and therapeutic strategy for Alzheimer's disease treatment.

PROCESS FOR DUST-FREE ENZYME MANUFACTURE

NARCIS (Netherlands)

Andela, C.; Feijen, Jan; Dillissen, Marc

1994-01-01

New enzyme granules are provided with improved properties. The granules are based on core particles having a good pore size and pore size distribution to allow an enzyme solution to enter into the particle. Accordingly, the core material comprises the enzyme in liquid form, thus eliminating the

Bio-processing of Agro-industrial Wastes for Production of Food-grade Enzymes: Progress and Prospects

Directory of Open Access Journals (Sweden)

Parmjit S Panesar

2016-10-01

Full Text Available Background and Objectives: In the era of global industrialization, enzymes are being used extensively in the various sectors including food processing. Owing to the high price of enzymes, various initiatives have been undertaken by the R&D sector for the development of new processes or improvement in the existing processes for production of cost effective enzymes. With the advancement in the field of biotechnology, different bioprocesses are being used for utilization of different agro-industrial residues for the production of various enzymes. This review focuses on different types of agro-industrial wastes and their utilization in the production of enzymes. The present scenario as well as the future scope of utilization of enzymes in the food industry has also been discussed.Results and Conclusion: The regulations from the various governmental as well as environmental agencies for the demand of cleaner environment have led to the advancement in various technologies for utilization of the wastes for the production of value-added products such as enzymes. Among the different types of fermentation, maximum work has been carried under solid state conditions by batch fermentation. The research has indicated the significant potential of agro-industrial wastes for production of food-grade enzymes in order to improve the economics of the process.Conflict of interests: The authors declare no conflict of interest.

A model-based framework for design of intensified enzyme-based processes

DEFF Research Database (Denmark)

Román-Martinez, Alicia

This thesis presents a generic and systematic model-based framework to design intensified enzyme-based processes. The development of the presented methodology was motivated by the needs of the bio-based industry for a more systematic approach to achieve intensification in its production plants...... in enzyme-based processes which have found significant application in the pharmaceutical, food, and renewable fuels sector. The framework uses model-based strategies for (bio)-chemical process design and optimization, including the use of a superstructure to generate all potential reaction......(s)-separation(s) options according to a desired performance criteria and a generic mathematical model represented by the superstructure to derive the specific models corresponding to a specific process option. In principle, three methods of intensification of bioprocess are considered in this thesis: 1. enzymatic one...

Modeling physiological processes in plankton on enzyme kinetic principles

Directory of Open Access Journals (Sweden)

Ted Packard

2004-04-01

Full Text Available Many ecologically important chemical transformations in the ocean are controlled by biochemical enzyme reactions in plankton. Nitrogenase regulates the transformation of N2 to ammonium in some cyanobacteria and serves as the entryway for N2 into the ocean biosphere. Nitrate reductase controls the reduction of NO3 to NO2 and hence new production in phytoplankton. The respiratory electron transfer system in all organisms links the carbon oxidation reactions of intermediary metabolism with the reduction of oxygen in respiration. Rubisco controls the fixation of CO2 into organic matter in phytoplankton and thus is the major entry point of carbon into the oceanic biosphere. In addition to these, there are the enzymes that control CO2 production, NH4 excretion and the fluxes of phosphate. Some of these enzymes have been recognized and researched by marine scientists in the last thirty years. However, until recently the kinetic principles of enzyme control have not been exploited to formulate accurate mathematical equations of the controlling physiological expressions. Were such expressions available they would increase our power to predict the rates of chemical transformations in the extracellular environment of microbial populations whether this extracellular environment is culture media or the ocean. Here we formulate from the principles of bisubstrate enzyme kinetics, mathematical expressions for the processes of NO3 reduction, O2 consumption, N2 fixation, total nitrogen uptake.

Process Simulation of enzymatic biodiesel production -at what cost can biodiesel be made with enzymes?

DEFF Research Database (Denmark)

Fjerbæk Søtoft, Lene; Christensen, Knud Villy; Rong, Benguang

as well as environmental impacts of the alternative process must be evaluated towards the conventional process. With process simulation tools, an evaluation will be carried out looking at what it will cost to produce biodiesel with enzymes. Different scenarios will be taken into account with variations...... in raw material prices, process designs and enzyme cost and performance....

Sildenafil Decreases BACE1 and Cathepsin B Levels and Reduces APP Amyloidogenic Processing in the SAMP8 Mouse.

Science.gov (United States)

Orejana, Lourdes; Barros-Miñones, Lucía; Jordan, Joaquin; Cedazo-Minguez, Angel; Tordera, Rosa M; Aguirre, Norberto; Puerta, Elena

2015-06-01

The senescence-accelerated mouse-prone 8 (SAMP8), used as a model of aging, displays many established pathological features of Alzheimer's disease. Cognitive impairments and increased levels of hyperphosphorylated tau are found in the hippocampus of SAMP8 mice along with an increased β-secretase activity and amyloid-β (Aβ) depositions that increase in number and extent with age. Based on a previous study from our laboratory showing an amelioration of cognitive impairments and tau pathology by sildenafil, in this study we tested whether this drug could also modulate the amyloid precursor protein amyloidogenic processing in this mouse model. Our results show that the protein levels of the β-secretases β-site amyloid precursor protein cleaving enzyme 1 and cathepsin B are higher in the hippocampus of 9-month-old SAMP8 mice than those of age-matched senescence-resistant-1. Sildenafil (7.5mg/kg for 4 weeks) attenuated learning and memory impairments shown by SAMP8 mice in the passive avoidance test. The increased expression of β-site amyloid precursor protein cleaving enzyme 1 was also reduced by sildenafil, an effect paralleled to decreases in the activities of two β-site amyloid precursor protein cleaving enzyme 1 modulators, calpain and cyclin-dependent kinase 5 protein. Interestingly, sildenafil enhanced both Akt and glycogen synthase kinase-3β (ser9) phosphorylation, which could be mediating the reduction in cathepsin B levels found in the hippocampus of sildenafil-treated SAMP8 mice. Sildenafil-induced reduction in β-site amyloid precursor protein cleaving enzyme 1 and cathepsin B expression in SAMP8 mice was associated with a decrease in hippocampal Aβ42 levels which, in turn, could mediate the parallel decline in glial fibrillary acidic protein expression observed in these animals. These findings highlight the therapeutic potential of sildenafil in Alzheimer's disease pathogenesis. © The Author 2014. Published by Oxford University Press on behalf of

Enzyme technology for precision functional food ingredient processes.

Science.gov (United States)

Meyer, Anne S

2010-03-01

A number of naturally occurring dietary substances may exert physiological benefits. The production of enhanced levels or particularly tailored versions of such candidate functional compounds can be targeted by enzymatic catalysis. The recent literature contains examples of enhancing bioavailability of iron via enzyme-catalyzed degradation of phytate in wheat bran, increasing diacyl-glycerol and conjugated linoleic acid levels by lipase action, enhancing the absorption of the citrus flavonoid hesperetin via rhamnosidase treatment, and obtaining solubilized dietary fiber via enzymatic modification of potato starch processing residues. Such targeted enzyme-catalyzed reactions provide new invention opportunities for designing functional foods with significant health benefits. The provision of well-defined naturally structured compounds can, moreover, assist in obtaining the much-needed improved understanding of the physiological benefits of complex natural substances.

Functional Enzyme-Based Approach for Linking Microbial Community Functions with Biogeochemical Process Kinetics

Energy Technology Data Exchange (ETDEWEB)

Li, Minjing [School; Qian, Wei-jun [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Gao, Yuqian [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Shi, Liang [School; Liu, Chongxuan [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; School

2017-09-28

The kinetics of biogeochemical processes in natural and engineered environmental systems are typically described using Monod-type or modified Monod-type models. These models rely on biomass as surrogates for functional enzymes in microbial community that catalyze biogeochemical reactions. A major challenge to apply such models is the difficulty to quantitatively measure functional biomass for constraining and validating the models. On the other hand, omics-based approaches have been increasingly used to characterize microbial community structure, functions, and metabolites. Here we proposed an enzyme-based model that can incorporate omics-data to link microbial community functions with biogeochemical process kinetics. The model treats enzymes as time-variable catalysts for biogeochemical reactions and applies biogeochemical reaction network to incorporate intermediate metabolites. The sequences of genes and proteins from metagenomes, as well as those from the UniProt database, were used for targeted enzyme quantification and to provide insights into the dynamic linkage among functional genes, enzymes, and metabolites that are necessary to be incorporated in the model. The application of the model was demonstrated using denitrification as an example by comparing model-simulated with measured functional enzymes, genes, denitrification substrates and intermediates

The contribution of enzymes and process chemicals to the life cycle of ethanol

International Nuclear Information System (INIS)

MacLean, Heather L; Spatari, Sabrina

2009-01-01

Most life cycle studies of biofuels have not examined the impact of process chemicals and enzymes, both necessary inputs to biochemical production and which vary depending upon the technology platform (feedstock, pretreatment and hydrolysis system). We examine whether this omission is warranted for sugar-platform technologies. We develop life cycle ('well-to-tank') case studies for a corn dry-mill and for one 'mature' and two near-term lignocellulosic ethanol technologies. Process chemical and enzyme inputs contribute only 3% of fossil energy use and greenhouse gas (GHG) emissions for corn ethanol. Assuming considerable improvement compared to current enzyme performance, the inputs for the near-term lignocellulosic technologies studied are found to be responsible for 30%-40% of fossil energy use and 30%-35% of GHG emissions, not an insignificant fraction given that these models represent technology developers' nth plant performance. Mature technologies which assume lower chemical and enzyme loadings, high enzyme specific activity and on-site production utilizing renewable energy would significantly improve performance. Although the lignocellulosic technologies modeled offer benefits over today's corn ethanol through reducing life cycle fossil energy demand and GHG emissions by factors of three and six, achieving those performance levels requires continued research into and development of the manufacture of low dose, high specific activity enzyme systems. Realizing the benefits of low carbon fuels through biological conversion will otherwise not be possible. Tracking the technological performance of process conversion materials remains an important step in measuring the life cycle performance of biofuels.

Transmembrane amyloid-related proteins in CSF as potential biomarkers for Alzheimer’s disease

Directory of Open Access Journals (Sweden)

Inmaculada eLopez-Font

2015-06-01

Full Text Available In the continuing search for new cerebrospinal fluid (CSF biomarkers for Alzheimer’s disease (AD, reasonable candidates are the secretase enzymes involved in the processing of the amyloid precursor protein (APP, as well as the large proteolytic cleavage fragments sAPPα and sAPPβ. The enzymatic activities of some of these secretases, such as BACE1 and TACE, have been investigated as potential AD biomarkers, and it has been assumed that these activities present in human CSF result from the soluble truncated forms of the membrane-bound enzymes. However, we and others recently identified soluble forms of BACE1 and APP in CSF containing the intracellular domains, as well as the multi-pass transmembrane presenilin-1 (PS1 and other subunits of γ-secretase. We also review recent findings that suggest that most of these soluble transmembrane proteins could display self-association properties based on hydrophobic and/or ionic interactions leading to the formation of heteromeric complexes. The oligomerization state of these potential new biomarkers needs to be taken into consideration for assessing their real potential as CSF biomarkers for AD by adequate molecular tools.

Composition and microstructure alteration of triticale grain surface after processing by enzymes of cellulase complex

Directory of Open Access Journals (Sweden)

Elena Kuznetsova

2016-01-01

Full Text Available It is found that the pericarp tissue of grain have considerable strength and stiffness, that has an adverse effect on quality of whole-grain bread. Thereby, there exists the need for preliminary chemical and biochemical processing of durable cell walls before industrial use. Increasingly used in the production of bread finds an artificial hybrid of the traditional grain crops of wheat and rye - triticale, grain which has high nutritional value. The purpose of this research was to evaluate the influence of cellulose complex (Penicillium canescens enzymes on composition and microstructure alteration of triticale grain surface, for grain used in baking. Triticale grain was processed by cellulolytic enzyme preparations with different composition (producer is Penicillium canescens. During experiment it is found that triticale grain processing by enzymes of cellulase complex leads to an increase in the content of water-soluble pentosans by 36.3 - 39.2%. The total amount of low molecular sugars increased by 3.8 - 10.5 %. Studies show that under the influence of enzymes the microstructure of the triticale grain surface is changing. Microphotographs characterizing grain surface structure alteration in dynamic (every 2 hours during 10 hours of substrate hydrolysis are shown. It is found that the depth and direction of destruction process for non-starch polysaccharides of grain integument are determined by the composition of the enzyme complex preparation and duration of exposure. It is found, that xylanase involved in the modification of hemicelluloses fiber having both longitudinal and radial orientation. Hydrolysis of non-starch polysaccharides from grain shells led to increase of antioxidant activity. Ferulic acid was identified in alcoholic extract of triticale grain after enzymatic hydrolysis under the influence of complex preparation containing cellulase, xylanase and β-glucanase. Grain processing by independent enzymes containing in complex

Hydrogen separation through tailored dual phase membranes with nominal composition BaCe0.8Eu0.2O3-δ:Ce0.8Y0.2O2-δ at intermediate temperatures

Science.gov (United States)

Ivanova, Mariya E.; Escolástico, Sonia; Balaguer, Maria; Palisaitis, Justinas; Sohn, Yoo Jung; Meulenberg, Wilhelm A.; Guillon, Olivier; Mayer, Joachim; Serra, Jose M.

2016-11-01

Hydrogen permeation membranes are a key element in improving the energy conversion efficiency and decreasing the greenhouse gas emissions from energy generation. The scientific community faces the challenge of identifying and optimizing stable and effective ceramic materials for H2 separation membranes at elevated temperature (400-800 °C) for industrial separations and intensified catalytic reactors. As such, composite materials with nominal composition BaCe0.8Eu0.2O3-δ:Ce0.8Y0.2O2-δ revealed unprecedented H2 permeation levels of 0.4 to 0.61 mL·min-1·cm-2 at 700 °C measured on 500 μm-thick-specimen. A detailed structural and phase study revealed single phase perovskite and fluorite starting materials synthesized via the conventional ceramic route. Strong tendency of Eu to migrate from the perovskite to the fluorite phase was observed at sintering temperature, leading to significant Eu depletion of the proton conducing BaCe0.8Eu0.2O3-δ phase. Composite microstructure was examined prior and after a variety of functional tests, including electrical conductivity, H2-permeation and stability in CO2 containing atmospheres at elevated temperatures, revealing stable material without morphological and structural changes, with segregation-free interfaces and no further diffusive effects between the constituting phases. In this context, dual phase material based on BaCe0.8Eu0.2O3-δ:Ce0.8Y0.2O2-δ represents a very promising candidate for H2 separating membrane in energy- and environmentally-related applications.

Enzymes in Fermented Fish.

Science.gov (United States)

Giyatmi; Irianto, H E

Fermented fish products are very popular particularly in Southeast Asian countries. These products have unique characteristics, especially in terms of aroma, flavor, and texture developing during fermentation process. Proteolytic enzymes have a main role in hydrolyzing protein into simpler compounds. Fermentation process of fish relies both on naturally occurring enzymes (in the muscle or the intestinal tract) as well as bacteria. Fermented fish products processed using the whole fish show a different characteristic compared to those prepared from headed and gutted fish. Endogenous enzymes like trypsin, chymotrypsin, elastase, and aminopeptidase are the most involved in the fermentation process. Muscle tissue enzymes like cathepsins, peptidases, transaminases, amidases, amino acid decarboxylases, glutamic dehydrogenases, and related enzymes may also play a role in fish fermentation. Due to the decreased bacterial number during fermentation, contribution of microbial enzymes to proteolysis may be expected prior to salting of fish. Commercial enzymes are supplemented during processing for specific purposes, such as quality improvement and process acceleration. In the case of fish sauce, efforts to accelerate fermentation process and to improve product quality have been studied by addition of enzymes such as papain, bromelain, trypsin, pepsin, and chymotrypsin. © 2017 Elsevier Inc. All rights reserved.

Rationalizing fragment based drug discovery for BACE1: insights from FB-QSAR, FB-QSSR, multi objective (MO-QSPR) and MIF studies.

Science.gov (United States)

Manoharan, Prabu; Vijayan, R S K; Ghoshal, Nanda

2010-10-01

The ability to identify fragments that interact with a biological target is a key step in FBDD. To date, the concept of fragment based drug design (FBDD) is increasingly driven by bio-physical methods. To expand the boundaries of QSAR paradigm, and to rationalize FBDD using In silico approach, we propose a fragment based QSAR methodology referred here in as FB-QSAR. The FB-QSAR methodology was validated on a dataset consisting of 52 Hydroxy ethylamine (HEA) inhibitors, disclosed by GlaxoSmithKline Pharmaceuticals as potential anti-Alzheimer agents. To address the issue of target selectivity, a major confounding factor in the development of selective BACE1 inhibitors, FB-QSSR models were developed using the reported off target activity values. A heat map constructed, based on the activity and selectivity profile of the individual R-group fragments, and was in turn used to identify superior R-group fragments. Further, simultaneous optimization of multiple properties, an issue encountered in real-world drug discovery scenario, and often overlooked in QSAR approaches, was addressed using a Multi Objective (MO-QSPR) method that balances properties, based on the defined objectives. MO-QSPR was implemented using Derringer and Suich desirability algorithm to identify the optimal level of independent variables (X) that could confer a trade-off between selectivity and activity. The results obtained from FB-QSAR were further substantiated using MIF (Molecular Interaction Fields) studies. To exemplify the potentials of FB-QSAR and MO-QSPR in a pragmatic fashion, the insights gleaned from the MO-QSPR study was reverse engineered using Inverse-QSAR in a combinatorial fashion to enumerate some prospective novel, potent and selective BACE1 inhibitors.

Rationalizing fragment based drug discovery for BACE1: insights from FB-QSAR, FB-QSSR, multi objective (MO-QSPR) and MIF studies

Science.gov (United States)

Manoharan, Prabu; Vijayan, R. S. K.; Ghoshal, Nanda

2010-10-01

The ability to identify fragments that interact with a biological target is a key step in FBDD. To date, the concept of fragment based drug design (FBDD) is increasingly driven by bio-physical methods. To expand the boundaries of QSAR paradigm, and to rationalize FBDD using In silico approach, we propose a fragment based QSAR methodology referred here in as FB-QSAR. The FB-QSAR methodology was validated on a dataset consisting of 52 Hydroxy ethylamine (HEA) inhibitors, disclosed by GlaxoSmithKline Pharmaceuticals as potential anti-Alzheimer agents. To address the issue of target selectivity, a major confounding factor in the development of selective BACE1 inhibitors, FB-QSSR models were developed using the reported off target activity values. A heat map constructed, based on the activity and selectivity profile of the individual R-group fragments, and was in turn used to identify superior R-group fragments. Further, simultaneous optimization of multiple properties, an issue encountered in real-world drug discovery scenario, and often overlooked in QSAR approaches, was addressed using a Multi Objective (MO-QSPR) method that balances properties, based on the defined objectives. MO-QSPR was implemented using Derringer and Suich desirability algorithm to identify the optimal level of independent variables ( X) that could confer a trade-off between selectivity and activity. The results obtained from FB-QSAR were further substantiated using MIF (Molecular Interaction Fields) studies. To exemplify the potentials of FB-QSAR and MO-QSPR in a pragmatic fashion, the insights gleaned from the MO-QSPR study was reverse engineered using Inverse-QSAR in a combinatorial fashion to enumerate some prospective novel, potent and selective BACE1 inhibitors.

Fermentation Process of Cocoa Based on Optimum Condition of Pulp PectinDepolymerization by Endogenous Pectolityc Enzymes

OpenAIRE

Ganda-Putra, G.P; Wrasiati, L.P; Wartini, N.M

2010-01-01

Pulp degradation during cocoa fermentation can be carried out by depolymerization process of pulp pectin using endogenous pectolytic enzymes at optimum condition. The objectives of this research were to study the effect of fermentation process based on optimum condition in terms of temperature and pH of pulp pectin depolymerization using endogenous pectolytic enzymes polygalakturonase (PG) and pectin metyl esterase (PME) and fermentation period in cocoa processing on quality characteristics o...

The common inhalation anesthetic isoflurane induces caspase activation and increases amyloid beta-protein level in vivo.

Science.gov (United States)

Xie, Zhongcong; Culley, Deborah J; Dong, Yuanlin; Zhang, Guohua; Zhang, Bin; Moir, Robert D; Frosch, Matthew P; Crosby, Gregory; Tanzi, Rudolph E

2008-12-01

An estimated 200 million patients worldwide have surgery each year. Anesthesia and surgery have been reported to facilitate emergence of Alzheimer's disease. The commonly used inhalation anesthetic isoflurane has previously been reported to induce apoptosis, and to increase levels and aggregation of Alzheimer's disease-associated amyloid beta-protein (Abeta) in cultured cells. However, the in vivo relevance has not been addressed. We therefore set out to determine effects of isoflurane on caspase activation and levels of beta-site amyloid precursor protein-cleaving enzyme (BACE) and Abeta in naive mice, using Western blot, immunohistochemistry, and reverse transcriptase polymerase chain reaction. Here we show for the first time that a clinically relevant isoflurane anesthesia (1.4% isoflurane for 2 hours) leads to caspase activation and modest increases in levels of BACE 6 hours after anesthesia in mouse brain. Isoflurane anesthesia induces caspase activation, and increases levels of BACE and Abeta up to 24 hours after anesthesia. Isoflurane may increase BACE levels by reducing BACE degradation. Moreover, the Abeta aggregation inhibitor, clioquinol, was able to attenuate isoflurane-induced caspase-3 activation in vivo. Given that transient insults to brain may lead to long-term brain damage, these findings suggest that isoflurane may promote Alzheimer's disease neuropathogenesis and, as such, have implications for use of isoflurane in humans, pending human study confirmation.

Enzyme Assay: An Investigative Approach to Enhance Science Process Skills

Science.gov (United States)

Vartak, Rekha; Ronad, Anupama; Ghanekar, Vikrant

2013-01-01

Scientific investigations play a vital role in teaching and learning the process of science. An investigative task that was developed for pre-university students is described here. The task involves extraction of an enzyme from a vegetable source and its detection by biochemical method. At the beginning of the experiment, a hypothesis is presented…

LaCoO3: Promising cathode material for protonic ceramic fuel cells based on a BaCe0.2Zr0.7Y0.1O3−δ electrolyte

DEFF Research Database (Denmark)

Ricote, Sandrine; Bonanos, Nikolaos; Lenrick, Filip

2012-01-01

Symmetric cells (cathode/electrolyte/cathode) were prepared using BaCe0.2Zr0.7Y0.1O3−δ (BCZY27) as proton conducting electrolyte and LaCoO3 (LC) infiltrated into a porous BCZY27 backbone as cathode. Single phased LC was formed after annealing in air at 600 °C for 2 h. Scanning electron micrograph...... that the presence of oxide ion conduction in the cathode material is not necessary for good performance.......Symmetric cells (cathode/electrolyte/cathode) were prepared using BaCe0.2Zr0.7Y0.1O3−δ (BCZY27) as proton conducting electrolyte and LaCoO3 (LC) infiltrated into a porous BCZY27 backbone as cathode. Single phased LC was formed after annealing in air at 600 °C for 2 h. Scanning electron micrographs...... showed the presence of the infiltrated LC in the full cathode depth. Transmission electron micrographs revealed LC grains (60–80 nm) covering partly the BCZY27 grains (200 nm–1 μm). Impedance spectra were recorded at 500 °C and 600 °C, varying the oxygen partial pressure and the water vapour pressure...

Long-term electromagnetic pulse exposure induces Abeta deposition and cognitive dysfunction through oxidative stress and overexpression of APP and BACE1.

Science.gov (United States)

Jiang, Da-Peng; Li, Jin-Hui; Zhang, Jie; Xu, Sheng-Long; Kuang, Fang; Lang, Hai-Yang; Wang, Ya-Feng; An, Guang-Zhou; Li, Jing; Guo, Guo-Zhen

2016-07-01

A progressively expanded literature has been devoted in the past years to the noxious or beneficial effects of electromagnetic field (EMF) to Alzheimer׳s disease (AD). This study concerns the relationship between electromagnetic pulse (EMP) exposure and the occurrence of AD in rats and the underlying mechanisms, focusing on the role of oxidative stress (OS). 55 healthy male Sprague Dawley (SD) rats were used and received continuous exposure for 8 months. Morris water maze (MWM) test was conducted to test the ability of cognitive and memory. The level of OS was detected by superoxide dismutase (SOD) activity and glutathione (GSH) content. We found that long-term EMP exposure induced cognitive damage in rats. The content of β-amyloid (Aβ) protein in hippocampus was increased after long-term EMP exposure. OS of hippocampal neuron was detected. Western blotting and immunohistochemistry (IHC) assay showed that the content of Aβ protein and its oligomers in EMP-exposed rats were higher than that of sham-exposed rats. The content of Beta Site App Cleaving Enzyme (BACE1) and microtubule-associated protein 1 light chain 3-II (LC3-II) in EMP-exposed rats hippocampus were also higher than that of sham-exposed rats. SOD activity and GSH content in EMP-exposed rats were lower than sham-exposed rats (p<0.05). Several mechanisms were proposed based on EMP exposure-induced OS, including increased amyloid precursor protein (APP) aberrant cleavage. Although further study is needed, the present results suggest that long-term EMP exposure is harmful to cognitive ability in rats and could induce AD-like pathological manifestation. Copyright © 2016 Elsevier B.V. All rights reserved.

Enzyme-substrate binding landscapes in the process of nitrile biodegradation mediated by nitrile hydratase and amidase.

Science.gov (United States)

Zhang, Yu; Zeng, Zhuotong; Zeng, Guangming; Liu, Xuanming; Chen, Ming; Liu, Lifeng; Liu, Zhifeng; Xie, Gengxin

2013-08-01

The continuing discharge of nitriles in various industrial processes has caused serious environmental consequences of nitrile pollution. Microorganisms possess several nitrile-degrading pathways by direct interactions of nitriles with nitrile-degrading enzymes. However, these interactions are largely unknown and difficult to experimentally determine but important for interpretation of nitrile metabolisms and design of nitrile-degrading enzymes with better nitrile-converting activity. Here, we undertook a molecular modeling study of enzyme-substrate binding modes in the bi-enzyme pathway for degradation of nitrile to acid. Docking results showed that the top substrates having favorable interactions with nitrile hydratase from Rhodococcus erythropolis AJ270 (ReNHase), nitrile hydratase from Pseudonocardia thermophila JCM 3095 (PtNHase), and amidase from Rhodococcus sp. N-771 (RhAmidase) were benzonitrile, 3-cyanopyridine, and L-methioninamide, respectively. We further analyzed the interactional profiles of these top poses with corresponding enzymes, showing that specific residues within the enzyme's binding pockets formed diverse contacts with substrates. This information on binding landscapes and interactional profiles is of great importance for the design of nitrile-degrading enzyme mutants with better oxidation activity toward nitriles or amides in the process of pollutant treatments.

Multi-enzyme catalyzed processes: Next generation biocatalysis

DEFF Research Database (Denmark)

Andrade Santacoloma, Paloma de Gracia; Sin, Gürkan; Gernaey, Krist

2011-01-01

Biocatalysis has been attracting increasing interest in recent years. Nevertheless, most studies concerning biocatalysis have been carried out using single enzymes (soluble or immobilized). Currently, multiple enzyme mixtures are attractive for the production of many compounds at an industrial...

Fluorescent turn-on determination of the activity of peptidases using peptide templated gold nanoclusters

International Nuclear Information System (INIS)

Luo, Junjun; Wang, Liqiang; Zeng, Ke; Shen, Congcong; Qian, Pin; Yang, Minghui; Rasooly, Avraham; Qu, Fengli

2016-01-01

The fluorescence intensity of gold nanoclusters (AuNCs) is inversely related to the length of a peptide immobilized on its surface. This finding has been exploited to design a turn-on fluorescent method for the determination of the activity of peptidase. The β-site amyloid precursor protein-cleaving enzyme 1 (BACE1) was chosen as a model peptidase. BACE1 cleaves the peptide substrates on AuNCs, and the fluorescence intensity of the AuNCs (at exCitation/emission wavelengths of 320/405 nm) carrying the rest of the cleaved peptide is significantly higher than that of the AuNCs with uncleaved peptide. Transmission electron microscopy revealed a decrease in the size of the AuNCs which is assumed cause fluorescence enhancement. The assay was applied to the determination of BACE1 activity in spiked cell lysates, and recoveries were between 96.9 and 104.0 %. (author)

Influence of fungal morphology on the performance of industrial fermentation processes for enzyme production

DEFF Research Database (Denmark)

Quintanilla Hernandez, Daniela Alejandra

Production of industrial enzymes is usually carried out as submerged aerobic fermentations. Filamentous microorganisms are widely used as hosts in these processes due to multiple advantages. Nevertheless, they also present major drawbacks, due to the unavoidable oxygen transfer limitations...... in this work, along with its correlation to viscosity and other process variables. Considerable research work has been conducted through the years to study fungal morphology and its relation to productivity. However, the work reported in the literature lacks relevant industrial data. In this work, a platform...... was developed which was able to produce high enzyme titers in comparison with what has been reported thus far in fed-batch fermentation using a soluble inducer (lactose). Different nitrogen sources were compared, and it was found that soy meal allowed for higher enzyme titers compared to what has been reported...

Process development of continuous glycerolysis in an immobilized enzyme-packed reactor for industrial monoacylglycerol production

DEFF Research Database (Denmark)

Damstrup, Marianne; Kiil, Søren; Jensen, Anker Degn

2007-01-01

Continuous and easily operated glycerolysis was studied in different lipase-packed columns to evaluate the most potential process set-ups for industrial monoacylglycerol (MAG) production. Practical design-related issues such as enzyme-filling degree, required reaction time, mass transfer investig......Continuous and easily operated glycerolysis was studied in different lipase-packed columns to evaluate the most potential process set-ups for industrial monoacylglycerol (MAG) production. Practical design-related issues such as enzyme-filling degree, required reaction time, mass transfer...

Cellulosic ethanol: interactions between cultivar and enzyme loading in wheat straw processing

Directory of Open Access Journals (Sweden)

Felby Claus

2010-11-01

Full Text Available Abstract Background Variations in sugar yield due to genotypic qualities of feedstock are largely undescribed for pilot-scale ethanol processing. Our objectives were to compare glucose and xylose yield (conversion and total sugar yield from straw of five winter wheat cultivars at three enzyme loadings (2.5, 5 and 10 FPU g-1 dm pretreated straw and to compare particle size distribution of cultivars after pilot-scale hydrothermal pretreatment. Results Significant interactions between enzyme loading and cultivars show that breeding for cultivars with high sugar yields under modest enzyme loading could be warranted. At an enzyme loading of 5 FPU g-1 dm pretreated straw, a significant difference in sugar yields of 17% was found between the highest and lowest yielding cultivars. Sugar yield from separately hydrolyzed particle-size fractions of each cultivar showed that finer particles had 11% to 21% higher yields than coarse particles. The amount of coarse particles from the cultivar with lowest sugar yield was negatively correlated with sugar conversion. Conclusions We conclude that genetic differences in sugar yield and response to enzyme loading exist for wheat straw at pilot scale, depending on differences in removal of hemicellulose, accumulation of ash and particle-size distribution introduced by the pretreatment.

Vacuolar processing enzyme: an executor of plant cell death.

Science.gov (United States)

Hara-Nishimura, Ikuko; Hatsugai, Noriyuki; Nakaune, Satoru; Kuroyanagi, Miwa; Nishimura, Mikio

2005-08-01

Apoptotic cell death in animals is regulated by cysteine proteinases called caspases. Recently, vacuolar processing enzyme (VPE) was identified as a plant caspase. VPE deficiency prevents cell death during hypersensitive response and cell death of limited cell layers at the early stage of embryogenesis. Because plants do not have macrophages, dying cells must degrade their materials by themselves. VPE plays an essential role in the regulation of the lytic system of plants during the processes of defense and development. VPE is localized in the vacuoles, unlike animal caspases, which are localized in the cytosol. Thus, plants might have evolved a regulated cellular suicide strategy that, unlike animal apoptosis, is mediated by VPE and the vacuoles.

Influence of enzymes on the oil extraction processes in aqueous media

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Ricochon Guillaume

2010-11-01

Full Text Available The methods of oil aqueous extraction process (AEP assisted by enzymes are, over the last 50 years, an alternative designed to replace traditional methods of extraction using organic solvents. To extract the oil using an AEP, the use of specific enzymes, able to hydrolyze some or all components of seeds, can significantly increase the yields of extraction. Hydrolyzing the different constituents of cell walls (cellulose, hemicellulose, pectins, proteins, etc., enzymes are able to enhance the liberation of the oil. A number of physico-chemical parameters must also be considered for the better expression of the enzymatic mixture, while maintaining the quality of oils and meals. This article presents the various factors influencing the release of oil in aqueous media and the main results obtained by this process on various substrates.

BACE1 inhibition by microdose lithium formulation NP03 rescues memory loss and early stage amyloid neuropathology.

Science.gov (United States)

Wilson, E N; Do Carmo, S; Iulita, M F; Hall, H; Ducatenzeiler, A; Marks, A R; Allard, S; Jia, D T; Windheim, J; Cuello, A C

2017-08-01

Lithium is first-line therapy for bipolar affective disorder and has recently been shown to have protective effects in populations at risk for Alzheimer's disease (AD). However, the mechanism underlying this protection is poorly understood and consequently limits its possible therapeutic application in AD. Moreover, conventional lithium formulations have a narrow therapeutic window and are associated with a severe side effect profile. Here we evaluated a novel microdose formulation of lithium, coded NP03, in a well-characterized rat model of progressive AD-like amyloid pathology. This formulation allows microdose lithium delivery to the brain in the absence of negative side effects. We found that NP03 rescued key initiating components of AD pathology, including inactivating GSK-3β, reducing BACE1 expression and activity, and reducing amyloid levels. Notably, NP03 rescued memory loss, impaired CRTC1 promoter binding of synaptic plasticity genes and hippocampal neurogenesis. These results raise the possibility that NP03 be of therapeutic value in the early or preclinical stages of AD.

Vacuolar processing enzyme in plant programmed cell death

Directory of Open Access Journals (Sweden)

Noriyuki eHatsugai

2015-04-01

Full Text Available Vacuolar processing enzyme (VPE is a cysteine proteinase originally identified as the proteinase responsible for the maturation and activation of vacuolar proteins in plants, and it is known to be an orthologue of animal asparaginyl endopeptidase (AEP/VPE/legumain. VPE has been shown to exhibit enzymatic properties similar to that of caspase 1, which is a cysteine protease that mediates the programmed cell death (PCD pathway in animals. Although there is limited sequence identity between VPE and caspase 1, their predicted three-dimensional structures revealed that the essential amino-acid residues for these enzymes form similar pockets for the substrate peptide YVAD. In contrast to the cytosolic localization of caspases, VPE is localized in vacuoles. VPE provokes vacuolar rupture, initiating the proteolytic cascade leading to PCD in the plant immune response. It has become apparent that the VPE-dependent PCD pathway is involved not only in the immune response, but also in the responses to a variety of stress inducers and in the development of various tissues. This review summarizes the current knowledge on the contribution of VPE to plant PCD and its role in vacuole-mediated cell death, and it also compares VPE with the animal cell death executor caspase 1.

Prion protein is decreased in Alzheimer's brain and inversely correlates with BACE1 activity, amyloid-β levels and Braak stage.

Directory of Open Access Journals (Sweden)

Isobel J Whitehouse

Full Text Available The cellular prion protein (PrP(C has been implicated in the development of Alzheimer's disease (AD. PrP(C decreases amyloid-β (Aβ production, which is involved in AD pathogenesis, by inhibiting β-secretase (BACE1 activity. Contactin 5 (CNTN5 has also been implicated in the development of AD by a genome-wide association study. Here we measured PrP(C and CNTN5 in frontal cortex samples from 24 sporadic AD and 24 age-matched control brains and correlated the expression of these proteins with markers of AD. PrP(C was decreased in sporadic AD compared to controls (by 49%, p = 0.014 but there was no difference in CNTN5 between sporadic AD and controls (p = 0.217. PrP(C significantly inversely correlated with BACE1 activity (rs = -0.358, p = 0.006, Aβ load (rs = -0.456, p = 0.001, soluble Aβ (rs = -0.283, p = 0.026 and insoluble Aβ (rs = -0.353, p = 0.007 and PrP(C also significantly inversely correlated with the stage of disease, as indicated by Braak tangle stage (rs = -0.377, p = 0.007. CNTN5 did not correlate with Aβ load (rs = 0.040, p = 0.393, soluble Aβ (rs = 0.113, p = 0.223 or insoluble Aβ (rs = 0.169, p = 0.125. PrP(C was also measured in frontal cortex samples from 9 Down's syndrome (DS and 8 age-matched control brains. In contrast to sporadic AD, there was no difference in PrP(C in the DS brains compared to controls (p = 0.625. These data are consistent with a role for PrP(C in regulating Aβ production and indicate that brain PrP(C level may be important in influencing the onset and progression of sporadic AD.

Processing of poultry feathers by alkaline keratin hydrolyzing enzyme from Serratia sp. HPC 1383.

Science.gov (United States)

Khardenavis, Anshuman A; Kapley, Atya; Purohit, Hemant J

2009-04-01

The present study describes the production and characterization of a feather hydrolyzing enzyme by Serratia sp. HPC 1383 isolated from tannery sludge, which was identified by the ability to form clear zones around colonies on milk agar plates. The proteolytic activity was expressed in terms of the micromoles of tyrosine released from substrate casein per ml per min (U/mL min). Induction of the inoculum with protein was essential to stimulate higher activity of the enzyme, with 0.03% feathermeal in the inoculum resulting in increased enzyme activity (45U/mL) that further increased to 90U/mL when 3d old inoculum was used. The highest enzyme activity, 130U/mL, was observed in the presence of 0.2% yeast extract. The optimum assay temperature and pH for the enzyme were found to be 60 degrees C and 10.0, respectively. The enzyme had a half-life of 10min at 60 degrees C, which improved slightly to 18min in presence of 1mM Ca(2+). Inhibition of the enzyme by phenylmethyl sulfonyl fluoride (PMSF) indicated that the enzyme was a serine protease. The enzyme was also partially inhibited (39%) by the reducing agent beta-mercaptoethanol and by divalent metal ions such as Zn(2+) (41% inhibition). However, Ca(2+) and Fe(2+) resulted in increases in enzyme activity of 15% and 26%, respectively. The kinetic constants of the keratinase were found to be 3.84 microM (K(m)) and 108.7 microM/mLmin (V(max)). These results suggest that this extracellular keratinase may be a useful alternative and eco-friendly route for handling the abundant amount of waste feathers or for applications in other industrial processes.

Secretome analysis of Trichoderma reesei and Aspergillus niger cultivated by submerged and sequential fermentation processes: Enzyme production for sugarcane bagasse hydrolysis.

Science.gov (United States)

Florencio, Camila; Cunha, Fernanda M; Badino, Alberto C; Farinas, Cristiane S; Ximenes, Eduardo; Ladisch, Michael R

2016-08-01

Cellulases and hemicellulases from Trichoderma reesei and Aspergillus niger have been shown to be powerful enzymes for biomass conversion to sugars, but the production costs are still relatively high for commercial application. The choice of an effective microbial cultivation process employed for enzyme production is important, since it may affect titers and the profile of protein secretion. We used proteomic analysis to characterize the secretome of T. reesei and A. niger cultivated in submerged and sequential fermentation processes. The information gained was key to understand differences in hydrolysis of steam exploded sugarcane bagasse for enzyme cocktails obtained from two different cultivation processes. The sequential process for cultivating A. niger gave xylanase and β-glucosidase activities 3- and 8-fold higher, respectively, than corresponding activities from the submerged process. A greater protein diversity of critical cellulolytic and hemicellulolytic enzymes were also observed through secretome analyses. These results helped to explain the 3-fold higher yield for hydrolysis of non-washed pretreated bagasse when combined T. reesei and A. niger enzyme extracts from sequential fermentation were used in place of enzymes obtained from submerged fermentation. An enzyme loading of 0.7 FPU cellulase activity/g glucan was surprisingly effective when compared to the 5-15 times more enzyme loadings commonly reported for other cellulose hydrolysis studies. Analyses showed that more than 80% consisted of proteins other than cellulases whose role is important to the hydrolysis of a lignocellulose substrate. Our work combined proteomic analyses and enzymology studies to show that sequential and submerged cultivation methods differently influence both titers and secretion profile of key enzymes required for the hydrolysis of sugarcane bagasse. The higher diversity of feruloyl esterases, xylanases and other auxiliary hemicellulolytic enzymes observed in the enzyme

Regulation-Structured Dynamic Metabolic Model Provides a Potential Mechanism for Delayed Enzyme Response in Denitrification Process

Energy Technology Data Exchange (ETDEWEB)

Song, Hyun-Seob; Thomas, Dennis G.; Stegen, James C.; Li, Minjing; Liu, Chongxuan; Song, Xuehang; Chen, Xingyuan; Fredrickson, Jim K.; Zachara, John M.; Scheibe, Timothy D.

2017-09-29

In a recent study of denitrification dynamics in hyporheic zone sediments, we observed a significant time lag (up to several days) in enzymatic response to the changes in substrate concentration. To explore an underlying mechanism and understand the interactive dynamics between enzymes and nutrients, we developed a trait-based model that associates a community’s traits with functional enzymes, instead of typically used species guilds (or functional guilds). This enzyme-based formulation allows to collectively describe biogeochemical functions of microbial communities without directly parameterizing the dynamics of species guilds, therefore being scalable to complex communities. As a key component of modeling, we accounted for microbial regulation occurring through transcriptional and translational processes, the dynamics of which was parameterized based on the temporal profiles of enzyme concentrations measured using a new signature peptide-based method. The simulation results using the resulting model showed several days of a time lag in enzymatic responses as observed in experiments. Further, the model showed that the delayed enzymatic reactions could be primarily controlled by transcriptional responses and that the dynamics of transcripts and enzymes are closely correlated. The developed model can serve as a useful tool for predicting biogeochemical processes in natural environments, either independently or through integration with hydrologic flow simulators.

Descriptive and predictive assessment of enzyme activity and enzyme related processes in biorefinery using IR spectroscopy and chemometrics

DEFF Research Database (Denmark)

Baum, Andreas

the understanding of the structural properties of the extracted pectin. Secondly, enzyme kinetics of biomass converting enzymes was examined in terms of measuring enzyme activity by spectral evolution profiling utilizing FTIR. Chemometric multiway methods were used to analyze the tensor datasets enabling the second......-order calibration advantage (reference Theory of Analytical chemistry). As PAPER 3 illustrates the method is universally applicable without the need of any external standards and was exemplified by performing quantitative enzyme activity determinations for glucose oxidase, pectin lyase and a cellolytic enzyme blend...... (Celluclast 1.5L). In PAPER 4, the concept is extended to quantify enzyme activity of two simultaneously acting enzymes, namely pectin lyase and pectin methyl esterase. By doing so the multiway methods PARAFAC, TUCKER3 and NPLS were compared and evaluated towards accuracy and precision....

Multifunctional Cellulolytic Enzymes Outperform Processive Fungal Cellulases for Coproduction of Nanocellulose and Biofuels.

Science.gov (United States)

Yarbrough, John M; Zhang, Ruoran; Mittal, Ashutosh; Vander Wall, Todd; Bomble, Yannick J; Decker, Stephen R; Himmel, Michael E; Ciesielski, Peter N

2017-03-28

Producing fuels, chemicals, and materials from renewable resources to meet societal demands remains an important step in the transition to a sustainable, clean energy economy. The use of cellulolytic enzymes for the production of nanocellulose enables the coproduction of sugars for biofuels production in a format that is largely compatible with the process design employed by modern lignocellulosic (second generation) biorefineries. However, yields of enzymatically produced nanocellulose are typically much lower than those achieved by mineral acid production methods. In this study, we compare the capacity for coproduction of nanocellulose and fermentable sugars using two vastly different cellulase systems: the classical "free enzyme" system of the saprophytic fungus, Trichoderma reesei (T. reesei) and the complexed, multifunctional enzymes produced by the hot springs resident, Caldicellulosiruptor bescii (C. bescii). We demonstrate by comparative digestions that the C. bescii system outperforms the fungal enzyme system in terms of total cellulose conversion, sugar production, and nanocellulose production. In addition, we show by multimodal imaging and dynamic light scattering that the nanocellulose produced by the C. bescii cellulase system is substantially more uniform than that produced by the T. reesei system. These disparities in the yields and characteristics of the nanocellulose produced by these disparate systems can be attributed to the dramatic differences in the mechanisms of action of the dominant enzymes in each system.

An overview of technologies for immobilization of enzymes and surface analysis techniques for immobilized enzymes

Science.gov (United States)

Mohamad, Nur Royhaila; Marzuki, Nur Haziqah Che; Buang, Nor Aziah; Huyop, Fahrul; Wahab, Roswanira Abdul

2015-01-01

The current demands of sustainable green methodologies have increased the use of enzymatic technology in industrial processes. Employment of enzyme as biocatalysts offers the benefits of mild reaction conditions, biodegradability and catalytic efficiency. The harsh conditions of industrial processes, however, increase propensity of enzyme destabilization, shortening their industrial lifespan. Consequently, the technology of enzyme immobilization provides an effective means to circumvent these concerns by enhancing enzyme catalytic properties and also simplify downstream processing and improve operational stability. There are several techniques used to immobilize the enzymes onto supports which range from reversible physical adsorption and ionic linkages, to the irreversible stable covalent bonds. Such techniques produce immobilized enzymes of varying stability due to changes in the surface microenvironment and degree of multipoint attachment. Hence, it is mandatory to obtain information about the structure of the enzyme protein following interaction with the support surface as well as interactions of the enzymes with other proteins. Characterization technologies at the nanoscale level to study enzymes immobilized on surfaces are crucial to obtain valuable qualitative and quantitative information, including morphological visualization of the immobilized enzymes. These technologies are pertinent to assess efficacy of an immobilization technique and development of future enzyme immobilization strategies. PMID:26019635

Pro-inflammatory interleukin-18 increases Alzheimer’s disease-associated amyloid-β production in human neuron-like cells

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Sutinen Elina M

2012-08-01

Full Text Available Abstract Background Alzheimer’s disease (AD involves increased accumulation of amyloid-β (Aβ plaques and neurofibrillary tangles as well as neuronal loss in various regions of the neocortex. Neuroinflammation is also present, but its role in AD is not fully understood. We previously showed increased levels of pro-inflammatory cytokine interleukin-18 (IL-18 in different regions of AD brains, where it co-localized with Aβ-plaques, as well as the ability of IL-18 to increase expression of glycogen synthase kinase-3β (GSK-3β and cyclin dependent kinase 5, involved in hyperphosphorylation of tau-protein. Elevated IL-18 has been detected in several risk conditions for AD, including obesity, type-II diabetes, and cardiovascular diseases as well as in stress. Methods We differentiated SH-SY5Y neuroblastoma cells as neuron-like and exposed them to IL-18 for various times. We examined the protein levels of amyloid-β precursor protein (APP and its processing products, its cleaving enzymes, involved in amyloidogenic processing of APP, and markers of apoptosis. Results IL-18 increased protein levels of the β-site APP-cleaving enzyme BACE-1, the N-terminal fragment of presenilin-1 and slightly presenilin enhancer 2, both of which are members of the γ-secretase complex, as well as Fe65, which is a binding protein of the C-terminus of APP and one regulator for GSK-3β. IL-18 also increased APP expression and phosphorylation, which preceded increased BACE-1 levels. Further, IL-18 altered APP processing, increasing Aβ40 production in particular, which was inhibited by IL-18 binding protein. Increased levels of soluble APPβ were detected in culture medium after the IL-18 exposure. IL-18 also increased anti-apoptotic bcl-xL levels, which likely counteracted the minor increase of the pro-apoptotic caspase-3. Lactate dehydrogenase activity in culture medium was unaffected. Conclusions The IL-18 induction of BACE-1, APP processing, and Aβ is likely to be

Proteinaceous inhibitors of carbohydrate-active enzymes in cereals – Implication in agriculture, cereal-processing and nutrition

DEFF Research Database (Denmark)

Juge, N.; Svensson, Birte

2006-01-01

Enzymes that degrade, modify, or create glycosidic bonds are involved in carbohydrate biosynthesis and remodelling. Microbial carbohydrate-active enzymes form the basis of current green technology in the food, feed, starch, paper and pulp industries and the revolution in genomics may offer long...... knowledge on their structure, function, and implication in cereal processing, agriculture and nutrition. (c) 2006 Society of Chemical Industry...

Lactic acid induces aberrant amyloid precursor protein processing by promoting its interaction with endoplasmic reticulum chaperone proteins.

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Yiwen Xiang

Full Text Available BACKGROUND: Lactic acid, a natural by-product of glycolysis, is produced at excess levels in response to impaired mitochondrial function, high-energy demand, and low oxygen availability. The enzyme involved in the production of β-amyloid peptide (Aβ of Alzheimer's disease, BACE1, functions optimally at lower pH, which led us to investigate a potential role of lactic acid in the processing of amyloid precursor protein (APP. METHODOLOGY/PRINCIPAL FINDINGS: Lactic acid increased levels of Aβ40 and 42, as measured by ELISA, in culture medium of human neuroblastoma cells (SH-SY5Y, whereas it decreased APP metabolites, such as sAPPα. In cell lysates, APP levels were increased and APP was found to interact with ER-chaperones in a perinuclear region, as determined by co-immunoprecipitation and fluorescence microscopy studies. Lactic acid had only a very modest effect on cellular pH, did increase the levels of ER chaperones Grp78 and Grp94 and led to APP aggregate formation reminiscent of aggresomes. CONCLUSIONS/SIGNIFICANCE: These findings suggest that sustained elevations in lactic acid levels could be a risk factor in amyloidogenesis related to Alzheimer's disease through enhanced APP interaction with ER chaperone proteins and aberrant APP processing leading to increased generation of amyloid peptides and APP aggregates.

Characterization of the aroma of a meatlike process flavoring from soybean-based enzyme-hydrolyzed vegetable protein.

Science.gov (United States)

Wu, Yi-Fang G; Cadwallader, Keith R

2002-05-08

Defatted soybean meal was converted into enzyme-hydrolyzed vegetable protein (E-HVP) using the proteolytic enzyme Flavorzyme. Total free amino acids increased by 40-fold after enzyme hydrolysis, with leucine being the most abundant, followed by phenylalanine, lysine, glutamine/glutamic acid, and alanine. Volatile components from a meatlike process flavoring made from E-HVP were isolated by direct solvent extraction (DSE)-high vacuum transfer (HVT), dynamic headspace sampling and static headspace sampling and analyzed by gas chromatography (GC)-mass spectrometry and GC-olfactometry. Aroma extract dilution analysis was used to establish a flavor dilution chromatogram of the DSE-HVT extract. Results of these complementary techniques indicated the importance of odorants of high (hydrogen sulfide and methanethiol), intermediate (2-methyl-3-furanthiol, 3-mercapto-2-pentanone, 2-furanmethanethiol, and 3-(methylthiol)propanal) and low volatility (maltol and Furaneol) in the overall aroma of the meatlike process flavoring.

The Amborella vacuolar processing enzyme family

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Valérie ePoncet

2015-08-01

Full Text Available Most vacuolar proteins are synthesized on rough endoplasmic reticulum as proprotein precursors and then transported to the vacuoles, where they are converted into their respective mature forms by vacuolar processing enzymes (VPEs. In the case of the seed storage proteins, this process is of major importance, as it conditions the establishment of vigorous seedlings. Toward the goal of identifying proteome signatures that could be associated with the origin and early diversification of angiosperms, we previously characterized the 11S-legumin-type of seed storage proteins from Amborella trichopoda, a rainforest shrub endemic to New Caledonia that is also the probable sister to all other angiosperms (Amborella Genome Project, 2013. In the present study, proteomic and genomic approaches were used to characterize the VPE family in this species. Three genes were found to encode VPEs in the Amborella’s genome. Phylogenetic analyses showed that the Amborella sequences grouped within two major clades of angiosperm VPEs, indicating that the duplication that generated the ancestors of these clades occurred before the most recent common ancestor of living angiosperms. A further important duplication within the VPE family appears to have occurred in common ancestor of the core eudicots, while many more recent duplications have also occurred in specific taxa, including both Arabidopsis thaliana and Amborella. An analysis of natural genetic variation for each of the three Amborella VPE genes revealed the absence of selective forces acting on intronic and exonic single-nucleotide polymorphisms among several natural Amborella populations of in New Caledonia.

BIOINSPIRED DESIGN AND DIRECTED EVOLUTION OF IRON CONTAINING ENZYMES FOR GREENSYNTHETIC PROCESSES AND BIOREMEDIATION

Science.gov (United States)

SU833912Title: Bioinspired Design and Directed Evolution of Iron Containing Enzymes for Green Synthetic Processes and BioremediationEdward I. Solomon, Shaun D. Wong, Lei Liu, Caleb B. Bell, IIICynthia Nolt-HelmsProject Period: August 15, 2008 - August 14,...

Full-length cellular β-secretase has a trimeric subunit stoichiometry, and its sulfur-rich transmembrane interaction site modulates cytosolic copper compartmentalization.

Science.gov (United States)

Liebsch, Filip; Aurousseau, Mark R P; Bethge, Tobias; McGuire, Hugo; Scolari, Silvia; Herrmann, Andreas; Blunck, Rikard; Bowie, Derek; Multhaup, Gerd

2017-08-11

The β-secretase (BACE1) initiates processing of the amyloid precursor protein (APP) into Aβ peptides, which have been implicated as central players in the pathology of Alzheimer disease. BACE1 has been described as a copper-binding protein and its oligomeric state as being monomeric, dimeric, and/or multimeric, but the native cellular stoichiometry has remained elusive. Here, by using single-molecule fluorescence and in vitro cross-linking experiments with photo-activatable unnatural amino acids, we show that full-length BACE1, independently of its subcellular localization, exists as trimers in human cells. We found that trimerization requires the BACE1 transmembrane sequences (TMSs) and cytoplasmic domains, with residues Ala 463 and Cys 466 buried within the trimer interface of the sulfur-rich core of the TMSs. Our 3D model predicts that the sulfur-rich core of the trimeric BACE1 TMS is accessible to metal ions, but copper ions did not trigger trimerization. The results of functional assays of endogenous BACE1 suggest that it has a role in intracellular copper compartmentalization by transferring cytosolic copper to intracellular compartments, while leaving the overall cellular copper concentration unaltered. Adding to existing physiological models, our results provide novel insight into the atypical interactions between copper and BACE1 and into its non-enzymatic activities. In conclusion, therapeutic Alzheimer disease prevention strategies aimed at decreasing BACE1 protein levels should be regarded with caution, because adverse effects in copper homeostasis may occur. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Enzymic lactose hydrolysis

Energy Technology Data Exchange (ETDEWEB)

Miller, J J; Brand, J C

1980-01-01

Acid or enzymic hydrolysis can be used to hydrolyze lactose. Advantages of both are compared and details of enzymic hydrolysis using yeast or fungal enzymes given. The new scheme outlined involves recycling lactase. Because lactose and lactase react to ultrafiltration (UF) membranes differently separation is possible. Milk or milk products are ultrafiltered to separate a concentrate from a lactose-rich permeate which is treated with lactase in a reactor until hydrolysis reaches a required level. The lactase can be removed by UF as it does not permeate the membrane, and it is recycled back to the reactor. Permeate from the second UF stage may or may not be recombined with the concentrate from the first stage to produce a low lactose product (analysis of a typical low-lactose dried whole milk is given). Batch or continuous processes are explained and a batch process without enzyme recovery is discussed. (Refs. 4).

The predominant molecular state of bound enzyme determines the strength and type of product inhibition in the hydrolysis of recalcitrant polysaccharides by processive enzymes.

Science.gov (United States)

Kuusk, Silja; Sørlie, Morten; Väljamäe, Priit

2015-05-01

Processive enzymes are major components of the efficient enzyme systems that are responsible for the degradation of the recalcitrant polysaccharides cellulose and chitin. Despite intensive research, there is no consensus on which step is rate-limiting for these enzymes. Here, we performed a comparative study of two well characterized enzymes, the cellobiohydrolase Cel7A from Hypocrea jecorina and the chitinase ChiA from Serratia marcescens. Both enzymes were inhibited by their disaccharide product, namely chitobiose for ChiA and cellobiose for Cel7A. The products behaved as noncompetitive inhibitors according to studies using the (14)C-labeled crystalline polymeric substrates (14)C chitin nanowhiskers and (14)C-labeled bacterial microcrystalline cellulose for ChiA and Cel7A, respectively. The resulting observed Ki (obs) values were 0.45 ± 0.08 mm for ChiA and 0.17 ± 0.02 mm for Cel7A. However, in contrast to ChiA, the Ki (obs) of Cel7A was an order of magnitude higher than the true Ki value governed by the thermodynamic stability of the enzyme-inhibitor complex. Theoretical analysis of product inhibition suggested that the inhibition strength and pattern can be accounted for by assuming different rate-limiting steps for ChiA and Cel7A. Measuring the population of enzymes whose active site was occupied by a polymer chain revealed that Cel7A was bound predominantly via its active site. Conversely, the active-site-mediated binding of ChiA was slow, and most ChiA exhibited a free active site, even when the substrate concentration was saturating for the activity. Collectively, our data suggest that complexation with the polymer chain is rate-limiting for ChiA, whereas Cel7A is limited by dissociation. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

PRODUCTION AND USES OF MICROBIAL ENZYMES FOR DAIRY PROCESSING

International Nuclear Information System (INIS)

EL-KABBANY, H.M.I.

2008-01-01

The isolation and identification of fungal producer from various Egyptian dairy products samples was studied. Among fungi testes, only one out of the 48 isolates was found to be positive yielded a suitable enzyme substitute (rennet) and identified as Cryphonectria parasitica (C. parasitica) and was found to be negative for mycotoxins. The highest growth and production of the crude enzyme were obtained from barley medium after an incubation period for 6-8 days at 25 0 C and pH 5. It was found also to be sensitive to gamma rays, since 2.5 kGy completely inactivated the germination of the spores while very low doses up to 0.05 kGy did not affect the production of rennet like enzyme (RLE). Precipitation of the crude enzyme produced by C. parasitica using ammonium sulphate (NH 4 ) 2 SO 4 gave the highest milk clotting activity (MCA) at 50 0 C. Further purification was achieved by using Sephadex G-100 to give pure RLE. MCA of the fungal and animal rennin proved to be essentially identical in milk containing various concentrations of CaCl 2 . An addition of 160 ppm of CaCl 2 increased the enzyme activity. The optimum temperature was 60 0 C while pre-heating thermophiles at 15 0 C for 10 minutes complete inactivation. Both rennins manifested comparable clotting activities in milk at pH 6

DYNAMIC MODELLING AND ADVANCED PREDICTIVE CONTROL OF A CONTINUOUS PROCESS OF ENZYME PURIFICATION

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Dechechi E.C.

1997-01-01

Full Text Available A dynamic mathematical model, simulation and computer control of a Continuous Affinity Recycle Extraction (CARE process, a protein purification technique based on protein adsorption on solid-phase adsorbents is described in this work. This process, consisting of three reactors, is a multivariable process with considerable time delay in the on-line analyses of the controlled variable. An advanced predictive control configuration, specifically the Dynamic Matrix Control (DMC, was applied. The DMC algorithm was applied in process schemes where the aim was to maintain constant the enzyme concentration in the outlet of the third reactor. The performance of the DMC controller was analyzed in the feed-flow disturbances and the results are presented.

Materials And Carbon Flow In A Waste Refinery Process Using Enzymes

DEFF Research Database (Denmark)

Tonini, Davide; Woods, M.; Astrup, Thomas

2011-01-01

Recovery of resources from mixed Municipal Solid Waste (MSW) is a crucial aspect of waste management practices. In this paper the materials and carbon flows of an innovative waste refinery process using enzymes are presented. Through enzymatic treatment the process produces two main streams from...... the initial mixed MSW: a bioslurry (liquefied paper and organics) and a solid fraction (non-degradable materials). The discussion is based on the performance of the process in separating recyclables and recovery Cbiogenic as well as nutrients from the input MSW. The results of MFA and SFA illustrate...... that the waste refinery has great potential for resource recovery: about 100% of the Cbiogenic and up to 90% of N and P can potentially be recovered in the bioslurry and returned to land after anaerobic digestion. Recovery of ferrous and non-ferrous material is estimated double compared to recovering the same...

Computational Biochemistry-Enzyme Mechanisms Explored.

Science.gov (United States)

Culka, Martin; Gisdon, Florian J; Ullmann, G Matthias

2017-01-01

Understanding enzyme mechanisms is a major task to achieve in order to comprehend how living cells work. Recent advances in biomolecular research provide huge amount of data on enzyme kinetics and structure. The analysis of diverse experimental results and their combination into an overall picture is, however, often challenging. Microscopic details of the enzymatic processes are often anticipated based on several hints from macroscopic experimental data. Computational biochemistry aims at creation of a computational model of an enzyme in order to explain microscopic details of the catalytic process and reproduce or predict macroscopic experimental findings. Results of such computations are in part complementary to experimental data and provide an explanation of a biochemical process at the microscopic level. In order to evaluate the mechanism of an enzyme, a structural model is constructed which can be analyzed by several theoretical approaches. Several simulation methods can and should be combined to get a reliable picture of the process of interest. Furthermore, abstract models of biological systems can be constructed combining computational and experimental data. In this review, we discuss structural computational models of enzymatic systems. We first discuss various models to simulate enzyme catalysis. Furthermore, we review various approaches how to characterize the enzyme mechanism both qualitatively and quantitatively using different modeling approaches. © 2017 Elsevier Inc. All rights reserved.

BAKERY ENZYMES IN CEREAL TECHNOLOGIES

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Václav Koman

2012-10-01

Full Text Available Normal 0 21 false false false SK X-NONE X-NONE Bread is the most common and traditional food in the world. For years, enzymes such as malt and fungal alpha-amylase have been used in bread making. Due to the changes in the baking industry and the ever-increasing demand for more natural products, enzymes have gained real importance in bread-making. If an enzyme is added, it is often destroyed by the heat during the baking process. For generations, enzymes have been used for the improvement of texture and appearance, enhancement of nutritional values and generation of appealing flavours and aromas. Enzymes used in bakery industry constitute nearly one third of the market. The bakery products have undergone radical improvements in quality over the past years in terms of flavour, texture and shelf-life. The the biggest contributor for these improvementsis the usage of enzymes. Present work seeks to systematically describe bakery enzymes, their classification, benefits, usage and chemical reactions in the bread making process.doi:10.5219/193

Immobilized enzymes: understanding enzyme - surface interactions at the molecular level.

Science.gov (United States)

Hoarau, Marie; Badieyan, Somayesadat; Marsh, E Neil G

2017-11-22

Enzymes immobilized on solid supports have important and industrial and medical applications. However, their uses are limited by the significant reductions in activity and stability that often accompany the immobilization process. Here we review recent advances in our understanding of the molecular level interactions between proteins and supporting surfaces that contribute to changes in stability and activity. This understanding has been facilitated by the application of various surface-sensitive spectroscopic techniques that allow the structure and orientation of enzymes at the solid/liquid interface to be probed, often with monolayer sensitivity. An appreciation of the molecular interactions between enzyme and surface support has allowed the surface chemistry and method of enzyme attachement to be fine-tuned such that activity and stability can be greatly enhanced. These advances suggest that a much wider variety of enzymes may eventually be amenable to immobilization as green catalysts.

Dry-grind processing using amylase corn and superior yeast to reduce the exogenous enzyme requirements in bioethanol production.

Science.gov (United States)

Kumar, Deepak; Singh, Vijay

2016-01-01

Conventional corn dry-grind ethanol production process requires exogenous alpha and glucoamylases enzymes to breakdown starch into glucose, which is fermented to ethanol by yeast. This study evaluates the potential use of new genetically engineered corn and yeast, which can eliminate or minimize the use of these external enzymes, improve the economics and process efficiencies, and simplify the process. An approach of in situ ethanol removal during fermentation was also investigated for its potential to improve the efficiency of high-solid fermentation, which can significantly reduce the downstream ethanol and co-product recovery cost. The fermentation of amylase corn (producing endogenous α-amylase) using conventional yeast and no addition of exogenous α-amylase resulted in ethanol concentration of 4.1 % higher compared to control treatment (conventional corn using exogenous α-amylase). Conventional corn processed with exogenous α-amylase and superior yeast (producing glucoamylase or GA) with no exogenous glucoamylase addition resulted in ethanol concentration similar to control treatment (conventional yeast with exogenous glucoamylase addition). Combination of amylase corn and superior yeast required only 25 % of recommended glucoamylase dose to complete fermentation and achieve ethanol concentration and yield similar to control treatment (conventional corn with exogenous α-amylase, conventional yeast with exogenous glucoamylase). Use of superior yeast with 50 % GA addition resulted in similar increases in yield for conventional or amylase corn of approximately 7 % compared to that of control treatment. Combination of amylase corn, superior yeast, and in situ ethanol removal resulted in a process that allowed complete fermentation of 40 % slurry solids with only 50 % of exogenous GA enzyme requirements and 64.6 % higher ethanol yield compared to that of conventional process. Use of amylase corn and superior yeast in the dry-grind processing industry

Enzymes - important players in green chemistry

Directory of Open Access Journals (Sweden)

Agata Tarczykowska

2017-09-01

Full Text Available Green chemistry has become a worldwide approach that leads to sustainable growth through application and development of its principles. A lot of work has to be put into designing new processes comprising of materials which do not emit pollutants to the atmosphere. Inventing new safer methods and finding less harmful products can be challenging. Enzymes are a great hope of scientists in the field of green chemistry. Enzymes as catalysts require mild conditions therefore it is a great way of saving resources such as energy or water. Processes with the use of enzymes have become more feasible by being more cost effective and eco friendly. Taking into account the benefits of green chemistry, enzyme biocatalysis has quickly replaced traditional chemical processes in several fields, and this substitution is going to reach even more areas because of new emerging technologies in enzyme engineering.

Impact of pH and Total Soluble Solids on Enzyme Inactivation Kinetics during High Pressure Processing of Mango (Mangifera indica) Pulp.

Science.gov (United States)

Kaushik, Neelima; Nadella, Tejaswi; Rao, P Srinivasa

2015-11-01

This study was undertaken with an aim to enhance the enzyme inactivation during high pressure processing (HPP) with pH and total soluble solids (TSS) as additional hurdles. Impact of mango pulp pH (3.5, 4.0, 4.5) and TSS (15, 20, 25 °Brix) variations on the inactivation of pectin methylesterase (PME), polyphenol oxidase (PPO), and peroxidase (POD) enzymes were studied during HPP at 400 to 600 MPa pressure (P), 40 to 70 °C temperature (T), and 6- to 20-min pressure-hold time (t). The enzyme inactivation (%) was modeled using second order polynomial equations with a good fit that revealed that all the enzymes were significantly affected by HPP. Response surface and contour models predicted the kinetic behavior of mango pulp enzymes adequately as indicated by the small error between predicted and experimental data. The predicted kinetics indicated that for a fixed P and T, higher pulse pressure effect and increased isobaric inactivation rates were possible at lower levels of pH and TSS. In contrast, at a fixed pH or TSS level, an increase in P or T led to enhanced inactivation rates, irrespective of the type of enzyme. PPO and POD were found to have similar barosensitivity, whereas PME was found to be most resistant to HPP. Furthermore, simultaneous variation in pH and TSS levels of mango pulp resulted in higher enzyme inactivation at lower pH and TSS during HPP, where the effect of pH was found to be predominant than TSS within the experimental domain. Exploration of additional hurdles such as pH, TSS, and temperature for enzyme inactivation during high pressure processing of fruits is useful from industrial point of view, as these parameters play key role in preservation process design. © 2015 Institute of Food Technologists®

Molecular dynamics of formation of TD lesioned DNA complexed with repair enzyme - onset of the enzymatic repair process

Energy Technology Data Exchange (ETDEWEB)

Pinak, Miroslav [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1999-12-01

To describe the first step of the enzymatic repair process (formation of complex enzyme-DNA), in which the thymine dimer (TD) part is removed from DNA, the 500 picosecond (ps) molecular dynamics (MD) simulation of TD lesioned DNA and part of repair enzyme cell (inclusive of catalytic center - Arg-22, Glu-23, Arg-26 and Thr-2) was performed. TD is UV originated lesion in DNA and T4 Endonuclease V is TD specific repair enzyme. Both molecules were located in the same simulation cell and their relative movement was examined. During the simulation the research was focused on the role of electrostatic energy in formation of complex enzyme-DNA. It is found, that during the first 100 ps of MD, the part of enzyme approaches the DNA surface at the TD lesion, interacts extensively by electrostatic and van der Walls interactions with TD part of DNA and forms complex that lasts stabile for 500 ps of MD. In the beginning of MD, the positive electrostatic interaction energy between part of enzyme and TD ({approx} +10 kcal/mol) drives enzyme towards the DNA molecule. Water-mediated hydrogen bonds between enzyme and DNA help to keep complex stabile. As a reference, the MD simulation of the identical system with native DNA molecule (two native thymines (TT) instead of TD) was performed. In this system the negative electrostatic interaction energy between part of enzyme and TT ({approx} -11 kcal/mol), in contrary to the positive one in the system with TD, doesn't drive enzyme towards DNA and complex is not formed. (author)

Molecular dynamics of formation of TD lesioned DNA complexed with repair enzyme - onset of the enzymatic repair process

International Nuclear Information System (INIS)

Pinak, Miroslav

1999-12-01

To describe the first step of the enzymatic repair process (formation of complex enzyme-DNA), in which the thymine dimer (TD) part is removed from DNA, the 500 picosecond (ps) molecular dynamics (MD) simulation of TD lesioned DNA and part of repair enzyme cell (inclusive of catalytic center - Arg-22, Glu-23, Arg-26 and Thr-2) was performed. TD is UV originated lesion in DNA and T4 Endonuclease V is TD specific repair enzyme. Both molecules were located in the same simulation cell and their relative movement was examined. During the simulation the research was focused on the role of electrostatic energy in formation of complex enzyme-DNA. It is found, that during the first 100 ps of MD, the part of enzyme approaches the DNA surface at the TD lesion, interacts extensively by electrostatic and van der Walls interactions with TD part of DNA and forms complex that lasts stabile for 500 ps of MD. In the beginning of MD, the positive electrostatic interaction energy between part of enzyme and TD (∼ +10 kcal/mol) drives enzyme towards the DNA molecule. Water-mediated hydrogen bonds between enzyme and DNA help to keep complex stabile. As a reference, the MD simulation of the identical system with native DNA molecule (two native thymines (TT) instead of TD) was performed. In this system the negative electrostatic interaction energy between part of enzyme and TT (∼ -11 kcal/mol), in contrary to the positive one in the system with TD, doesn't drive enzyme towards DNA and complex is not formed. (author)

Applications of Microbial Enzymes in Food Industry

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Binod Parameswaran

2018-01-01

Full Text Available The use of enzymes or microorganisms in food preparations is an age-old process. With the advancement of technology, novel enzymes with wide range of applications and specificity have been developed and new application areas are still being explored. Microorganisms such as bacteria, yeast and fungi and their enzymes are widely used in several food preparations for improving the taste and texture and they offer huge economic benefits to industries. Microbial enzymes are the preferred source to plants or animals due to several advantages such as easy, cost-effective and consistent production. The present review discusses the recent advancement in enzyme technology for food industries. A comprehensive list of enzymes used in food processing, the microbial source of these enzymes and the wide range of their application are discussed.

Engineering Cellulase Enzymes for Bioenergy

Science.gov (United States)

Atreya, Meera Elizabeth

Sustainable energy sources, such as biofuels, offer increasingly important alternatives to fossil fuels that contribute less to global climate change. The energy contained within cellulosic biofuels derives from sunlight energy stored in the form of carbon-carbon bonds comprising sugars such as glucose. Second-generation biofuels are produced from lignocellulosic biomass feedstocks, including agricultural waste products and non-food crops like Miscanthus, that contain lignin and the polysaccharides hemicellulose and cellulose. Cellulose is the most abundant biological material on Earth; it is a polymer of glucose and a structural component of plant cell walls. Accessing the sugar is challenging, as the crystalline structure of cellulose resists degradation; biochemical and thermochemical means can be used to depolymerize cellulose. Cellulase enzymes catalyze the biochemical depolymerization of cellulose into glucose. Glucose can be used as a carbon source for growth of a biofuel-producing microorganism. When it converts glucose to a hydrocarbon fuel, this microbe completes the biofuels process of transforming sunlight energy into accessible, chemical energy capable of replacing non-renewable transportation fuels. Due to strong intermolecular interactions between polymer chains, cellulose is significantly more challenging to depolymerize than starch, a more accessible polymer of glucose utilized in first-generation biofuels processes (often derived from corn). While most mammals cannot digest cellulose (dietary fiber), certain fungi and bacteria produce cellulase enzymes capable of hydrolyzing it. These organisms secrete a wide variety of glycoside hydrolase and other classes of enzymes that work in concert. Because cellulase enzymes are slow-acting and expensive to produce, my aim has been to improve the properties of these enzymes as a means to make a cellulosic biofuels process possible that is more efficient and, consequently, more economical than current

Improving digestive utilization of fiber-rich feedstuffs in pigs and poultry by processing and enzyme technologies: A review

NARCIS (Netherlands)

Vries, de S.; Pustjens, A.M.; Schols, H.A.; Hendriks, W.H.; Gerrits, W.J.J.

2012-01-01

The effects of processing technologies, whether or not combined with cell wall degrading enzymes, on the physicochemical properties of non-starch polysaccharides (NSP) and the resulting effects on NSP degradation in both pigs and poultry were reviewed. Evaluation of the effects of processing

Extracellular Enzyme Composition and Functional Characteristics of Aspergillus niger An-76 Induced by Food Processing Byproducts and Based on Integrated Functional Omics.

Science.gov (United States)

Liu, Lin; Gong, Weili; Sun, Xiaomeng; Chen, Guanjun; Wang, Lushan

2018-02-07

Byproducts of food processing can be utilized for the production of high-value-added enzyme cocktails. In this study, we utilized integrated functional omics technology to analyze composition and functional characteristics of extracellular enzymes produced by Aspergillus niger grown on food processing byproducts. The results showed that oligosaccharides constituted by arabinose, xylose, and glucose in wheat bran were able to efficiently induce the production of extracellular enzymes of A. niger. Compared with other substrates, wheat bran was more effective at inducing the secretion of β-glucosidases from GH1 and GH3 families, as well as >50% of proteases from A1-family aspartic proteases. Compared with proteins induced by single wheat bran or soybean dregs, the protein yield induced by their mixture was doubled, and the time required to reach peak enzyme activity was shortened by 25%. This study provided a technical platform for the complex formulation of various substrates and functional analysis of extracellular enzymes.

Dynamic enzyme docking to the ribosome coordinates N-terminal processing with polypeptide folding.

Science.gov (United States)

Sandikci, Arzu; Gloge, Felix; Martinez, Michael; Mayer, Matthias P; Wade, Rebecca; Bukau, Bernd; Kramer, Günter

2013-07-01

Newly synthesized polypeptides undergo various cotranslational maturation steps, including N-terminal enzymatic processing, chaperone-assisted folding and membrane targeting, but the spatial and temporal coordination of these steps is unclear. We show that Escherichia coli methionine aminopeptidase (MAP) associates with ribosomes through a charged loop that is crucial for nascent-chain processing and cell viability. MAP competes with peptide deformylase (PDF), the first enzyme to act on nascent chains, for binding sites at the ribosomal tunnel exit. PDF has extremely fast association and dissociation kinetics, which allows it to frequently sample ribosomes and ensure the processing of nascent chains after their emergence. Premature recruitment of the chaperone trigger factor, or polypeptide folding, negatively affect processing efficiency. Thus, the fast ribosome association kinetics of PDF and MAP are crucial for the temporal separation of nascent-chain processing from later maturation events, including chaperone recruitment and folding.

Industrial Applications of Enzymes: Recent Advances, Techniques, and Outlooks

Directory of Open Access Journals (Sweden)

Jordan Chapman

2018-06-01

Full Text Available Enzymes as industrial biocatalysts offer numerous advantages over traditional chemical processes with respect to sustainability and process efficiency. Enzyme catalysis has been scaled up for commercial processes in the pharmaceutical, food and beverage industries, although further enhancements in stability and biocatalyst functionality are required for optimal biocatalytic processes in the energy sector for biofuel production and in natural gas conversion. The technical barriers associated with the implementation of immobilized enzymes suggest that a multidisciplinary approach is necessary for the development of immobilized biocatalysts applicable in such industrial-scale processes. Specifically, the overlap of technical expertise in enzyme immobilization, protein and process engineering will define the next generation of immobilized biocatalysts and the successful scale-up of their induced processes. This review discusses how biocatalysis has been successfully deployed, how enzyme immobilization can improve industrial processes, as well as focuses on the analysis tools critical for the multi-scale implementation of enzyme immobilization for increased product yield at maximum market profitability and minimum logistical burden on the environment and user.

The mechanisms of Excited states in enzymes

DEFF Research Database (Denmark)

Petersen, Frederic Nicolas Rønne; Bohr, Henrik

2010-01-01

Enzyme catalysis is studied on the basis of excited state processes, which are of electronic, vibrational and thermal nature. The ways of achieving the excited state, such as photo-absorption and ligand binding, are discussed and exemplified by various cases of enzymes.......Enzyme catalysis is studied on the basis of excited state processes, which are of electronic, vibrational and thermal nature. The ways of achieving the excited state, such as photo-absorption and ligand binding, are discussed and exemplified by various cases of enzymes....

The use of enzymes for beer brewing

NARCIS (Netherlands)

Donkelaar, van Laura H.G.; Mostert, Joost; Zisopoulos, Filippos K.; Boom, Remko M.; Goot, van der Atze Jan

2016-01-01

The exergetic performance of beer produced by the conventional malting and brewing process is compared with that of beer produced using an enzyme-assisted process. The aim is to estimate if the use of an exogenous enzyme formulation reduces the environmental impact of the overall brewing process.

Enzyme recycling in lignocellulosic biorefineries

DEFF Research Database (Denmark)

Jørgensen, Henning; Pinelo, Manuel

2017-01-01

platform. Cellulases are the most important enzymes required in this process, but the complex nature of lignocellulose requires several other enzymes (hemicellulases and auxiliary enzymes) for efficient hydrolysis. Enzyme recycling increases the catalytic productivity of the enzymes by reusing them...... for several batches of hydrolysis, and thereby reduces the overall cost associated with the hydrolysis. Research on this subject has been ongoing for many years and several promising technologies and methods have been developed and demonstrated. But only in a very few cases have these technologies been...... upscaled and tested in industrial settings, mainly because of many difficulties with recycling of enzymes from the complex lignocellulose hydrolyzate at industrially relevant conditions, i.e., high solids loadings. The challenges are associated with the large number of different enzymes required...

Enzymes from Higher Eukaryotes for Industrial Biocatalysis

Directory of Open Access Journals (Sweden)

Zhibin Liu

2004-01-01

Full Text Available The industrial production of fine chemicals, feed and food ingredients, pharmaceuticals, agrochemicals and their respective intermediates relies on an increasing application of biocatalysis, i.e. on enzyme or whole-cell catalyzed conversions of molecules. Simple procedures for discovery, cloning and over-expression as well as fast growth favour fungi, yeasts and especially bacteria as sources of biocatalysts. Higher eukaryotes also harbour an almost unlimited number of potential biocatalysts, although to date the limited supply of enzymes, the high heterogeneity of enzyme preparations and the hazard of infectious contaminants keep some interesting candidates out of reach for industrial bioprocesses. In the past only a few animal and plant enzymes from agricultural waste materials were employed in food processing. The use of bacterial expression strains or non-conventional yeasts for the heterologous production of efficient eukaryotic enzymes can overcome the bottleneck in enzyme supply and provide sufficient amounts of homogenous enzyme preparations for reliable and economically feasible applications at large scale. Ideal enzymatic processes represent an environmentally friendly, »near-to-completion« conversion of (mostly non-natural substrates to pure products. Recent developments demonstrate the commercial feasibility of large-scale biocatalytic processes employing enzymes from higher eukaryotes (e.g. plants, animals and also their usefulness in some small-scale industrial applications.

Enzyme-MOF (metal-organic framework) composites.

Science.gov (United States)

Lian, Xizhen; Fang, Yu; Joseph, Elizabeth; Wang, Qi; Li, Jialuo; Banerjee, Sayan; Lollar, Christina; Wang, Xuan; Zhou, Hong-Cai

2017-06-06

The ex vivo application of enzymes in various processes, especially via enzyme immobilization techniques, has been extensively studied in recent years in order to enhance the recyclability of enzymes, to minimize enzyme contamination in the product, and to explore novel horizons for enzymes in biomedical applications. Possessing remarkable amenability in structural design of the frameworks as well as almost unparalelled surface tunability, Metal-Organic Frameworks (MOFs) have been gaining popularity as candidates for enzyme immobilization platforms. Many MOF-enzyme composites have achieved unprecedented results, far outperforming free enzymes in many aspects. This review summarizes recent developments of MOF-enzyme composites with special emphasis on preparative techniques and the synergistic effects of enzymes and MOFs. The applications of MOF-enzyme composites, primarily in transferation, catalysis and sensing, are presented as well. The enhancement of enzymatic activity of the composites over free enzymes in biologically incompatible conditions is emphasized in many cases.

Cellulolytic enzyme compositions and uses thereof

Energy Technology Data Exchange (ETDEWEB)

Iyer, Prashant; Gaspar, Armindo Ribiero; Croonenberghs, James; Binder, Thomas P.

2017-07-25

The present invention relates enzyme composition comprising a cellulolytic preparation and an acetylxylan esterase (AXE); and the used of cellulolytic enzyme compositions for hydrolyzing acetylated cellulosic material. Finally the invention also relates to processes of producing fermentation products from acetylated cellulosic materials using a cellulolytic enzyme composition of the invention.

Allosteric regulation of epigenetic modifying enzymes.

Science.gov (United States)

Zucconi, Beth E; Cole, Philip A

2017-08-01

Epigenetic enzymes including histone modifying enzymes are key regulators of gene expression in normal and disease processes. Many drug development strategies to target histone modifying enzymes have focused on ligands that bind to enzyme active sites, but allosteric pockets offer potentially attractive opportunities for therapeutic development. Recent biochemical studies have revealed roles for small molecule and peptide ligands binding outside of the active sites in modulating the catalytic activities of histone modifying enzymes. Here we highlight several examples of allosteric regulation of epigenetic enzymes and discuss the biological significance of these findings. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bioethanol from lignocellulose - pretreatment, enzyme immobilization and hydrolysis kinetics

DEFF Research Database (Denmark)

Tsai, Chien Tai

, the cost of enzyme is still the bottle neck, re-using the enzyme is apossible way to reduce the input of enzyme in the process. In the point view of engineering, the prediction of enzymatic hydrolysis kinetics under different substrate loading, enzyme combination is usful for process design. Therefore...... lignocellulose is the required high cellulase enzyme dosages that increase the processing costs. One method to decrease the enzyme dosage is to re-use BG, which hydrolyze the soluble substrate cellobiose. Based on the hypothesis that immobilized BG can be re-used, how many times the enzyme could be recycled...... liquid and pretreatment time can be reduced, the influence of substrate concentration, pretreatment time and temperature were investigated and optimized. Pretreatment of barley straw by [EMIM]Ac, correlative models were constructed using 3 different pretreatment parameters (temperature, time...

Highly efficient enzyme encapsulation in a protein nanocage: towards enzyme catalysis in a cellular nanocompartment mimic

Science.gov (United States)

Schoonen, Lise; Nolte, Roeland J. M.; van Hest, Jan C. M.

2016-07-01

The study of enzyme behavior in small nanocompartments is crucial for the understanding of biocatalytic processes in the cellular environment. We have developed an enzymatic conjugation strategy to attach a model enzyme to the interior of a cowpea chlorotic mottle virus capsid. It is shown that with this methodology high encapsulation efficiencies can be achieved. Additionally, we demonstrate that the encapsulation does not affect the enzyme performance in terms of a decreased activity or a hampered substrate diffusion. Finally, it is shown that the encapsulated enzymes are protected against proteases. We believe that our strategy can be used to study enzyme kinetics in an environment that approaches physiological conditions.The study of enzyme behavior in small nanocompartments is crucial for the understanding of biocatalytic processes in the cellular environment. We have developed an enzymatic conjugation strategy to attach a model enzyme to the interior of a cowpea chlorotic mottle virus capsid. It is shown that with this methodology high encapsulation efficiencies can be achieved. Additionally, we demonstrate that the encapsulation does not affect the enzyme performance in terms of a decreased activity or a hampered substrate diffusion. Finally, it is shown that the encapsulated enzymes are protected against proteases. We believe that our strategy can be used to study enzyme kinetics in an environment that approaches physiological conditions. Electronic supplementary information (ESI) available: Experimental procedures for the cloning, expression, and purification of all proteins, as well as supplementary figures and calculations. See DOI: 10.1039/c6nr04181g

Enzyme technology: Key to selective biorefining

DEFF Research Database (Denmark)

Meyer, Anne S.

2014-01-01

to the reaction is a unique trait of enzyme catalysis. Since enzyme selectivity means that a specific reaction is catalysed between particular species to produce definite products, enzymes are particularly fit for converting specific compounds in mixed biomass streams. Since enzymes are protein molecules...... their rational use in biorefinery processes requires an understanding of the basic features of enzymes and reaction traits with respect to specificity, kinetics, reaction optima, stability and structure-function relations – we are now at a stage where it is possible to use nature’s enzyme structures as starting...... point and then improve the functional traits by targeted mutation of the protein. The talk will display some of our recent hypotheses related to enzyme action, recently obtained results within knowledge-based enzyme improvements as well as cast light on research methods used in optimizing enzyme...

The use of enzymes for beer brewing: Thermodynamic comparison on resource use

International Nuclear Information System (INIS)

Donkelaar, Laura H.G. van; Mostert, Joost; Zisopoulos, Filippos K.; Boom, Remko M.; Goot, Atze-Jan van der

2016-01-01

The exergetic performance of beer produced by the conventional malting and brewing process is compared with that of beer produced using an enzyme-assisted process. The aim is to estimate if the use of an exogenous enzyme formulation reduces the environmental impact of the overall brewing process. The exergy efficiency of malting was 77%. The main exergy losses stem from the use of natural gas for kilning and from starch loss during germination. The exergy efficiency of the enzyme production process ranges between 20% and 42% depending on if the by-product was considered useful. The main exergy loss was due to high power requirement for fermentation. The total exergy input in the enzyme production process was 30 times the standard chemical exergy of the enzyme, which makes it exergetically expensive. Nevertheless, the total exergy input for the production of 100 kg beer was larger for the conventional process (441 MJ) than for the enzyme-assisted process (354 MJ). Moreover, beer produced using enzymes reduced the use of water, raw materials and natural gas by 7%, 14% and 78% respectively. Consequently, the exergy loss in the enzyme production process is compensated by the prevention of exergy loss in the total beer brewing process. - Highlights: • The exergetic production costs of enzymes are ±30 times their standard chemical exergy. • These costs of enzymes should be taken into account in exergy analysis. • Enzyme-assisted brewing is more exergy efficient than brewing with malted barley. • Enzyme-assisted brewing saves raw material, water and energy.

Enzyme Immobilization: An Overview on Methods, Support Material, and Applications of Immobilized Enzymes.

Science.gov (United States)

Sirisha, V L; Jain, Ankita; Jain, Amita

Immobilized enzymes can be used in a wide range of processes. In recent years, a variety of new approaches have emerged for the immobilization of enzymes that have greater efficiency and wider usage. During the course of the last two decades, this area has rapidly expanded into a multidisciplinary field. This current study is a comprehensive review of a variety of literature produced on the different enzymes that have been immobilized on various supporting materials. These immobilized enzymes have a wide range of applications. These include applications in the sugar, fish, and wine industries, where they are used for removing organic compounds from waste water. This study also reviews their use in sophisticated biosensors for metabolite control and in situ measurements of environmental pollutants. Immobilized enzymes also find significant application in drug metabolism, biodiesel and antibiotic production, bioremediation, and the food industry. The widespread usage of immobilized enzymes is largely due to the fact that they are cheaper, environment friendly, and much easier to use when compared to equivalent technologies. © 2016 Elsevier Inc. All rights reserved.

Synthesis of ceramic BaCe_0_._7Zr_0_,_1Y_0_._2O_3_-_δ electrolyte containing ZnO through the method hidrogel

International Nuclear Information System (INIS)

Vieira, J.H.A.; Fagury Neto, E.; Rabelo, A.A.

2014-01-01

The solid oxide fuel cells are promising sources of sustainable energy, once they produce electricity from an electrochemical reaction only with steam water as the product of this reaction. In this paper the synthesis of ceramic electrolyte BaCe_0_._7Zr_0_._1Y_0_._2O_3_-_δ using the hydrogel method which involves using an organic gelatin inexpensive and nontoxic modifying the conventional route of polymeric precursor was performed. It was used different amounts of the sintering additive ZnO to decrease the sintering temperature, typically around 1600 °C, towards a minimum relative density of 95%. The polymeric resin was pyrolyzed at 300 °C, subjected to calcination at 600 °C and sintering at temperatures of 1350, 1400 and 1450 °C for 2 hours. Characterizations were carried out by determination of relative density and apparent porosity and using the techniques of differential thermal analysis and simultaneous thermogravimetric, X-ray diffraction and scanning electron microscopy.(author)

Mycelial growth interactions and mannan-degrading enzyme ...

African Journals Online (AJOL)

STORAGESEVER

2009-05-18

May 18, 2009 ... enzymes (Frost and Moss, 1987). However, microbial enzymes are more in use due to cheaper substrates and ease of process modification. In microbial enzyme and biomass production, defined mixed culture method in which more than one organism grows simultaneously can result in increased biomass ...

Design and modelling of enzyme/poly-pyrrole modified electrodes for bio-catalyzed electro-synthesis processes

International Nuclear Information System (INIS)

Gros, Pierre

1996-01-01

This research thesis reports a study which aims at developing, analyzing and integrating an electrode-enzyme interface within an electro-enzymatic reactor to develop electrochemical biosensors. The adopted method comprises a confinement of the enzyme at the electrode surface by means of an electro-formed poly-pyrrole film. The author reports an experimental and theoretical study of the coupling between electrochemical reaction, enzymatic reaction and matter transfer in the polymer in order to better understand the operation of so-modified electrodes. Different parameters have an influence on the reaction rate. A numerical model (validated by experiments) allows the identification of the reaction limiting stages. A new elaboration protocol allows the polymer permeability to be increased. The interface is first applied to the reduction of the NAD coenzyme, and the process is also applied to the production of gluconic acid [fr

Enzymes: The possibility of production and applications

Directory of Open Access Journals (Sweden)

Petronijević Živomir B.

2003-01-01

Full Text Available Enzymes are biological catalysts with increasing application in the food pharmaceutical, cosmetic, textile and chemical industry. They are also important as reagents in chemical analysis, leather fabrications and as targets for the design of new drugs. Keeping in mind the growing need to replace classical chemical processes by alternative ones, because of ever growing environmental pollution, it is important that enzyme and other biotechnological processes are economical. Therefore, price decrease and stability and enzyme preparation efficiency increase are required more and more. This paper presents a short review of methods for yield increase and the improvement of the quality of enzyme products as commercial products, as well as a review of the possibilities of their application.

Metabolic Characterization of Intact Cells Reveals Intracellular Amyloid Beta but Not Its Precursor Protein to Reduce Mitochondrial Respiration

Science.gov (United States)

Schaefer, Patrick M.; von Einem, Bjoern; Walther, Paul; Calzia, Enrico; von Arnim, Christine A. F.

2016-01-01

One hallmark of Alzheimer´s disease are senile plaques consisting of amyloid beta (Aβ), which derives from the processing of the amyloid precursor protein (APP). Mitochondrial dysfunction has been linked to the pathogenesis of Alzheimer´s disease and both Aβ and APP have been reported to affect mitochondrial function in isolated systems. However, in intact cells, considering a physiological localization of APP and Aβ, it is pending what triggers the mitochondrial defect. Thus, the aim of this study was to dissect the impact of APP versus Aβ in inducing mitochondrial alterations with respect to their subcellular localization. We performed an overexpression of APP or beta-site amyloid precursor protein cleaving enzyme 1 (BACE1), increasing APP and Aβ levels or Aβ alone, respectively. Conducting a comprehensive metabolic characterization we demonstrate that only APP overexpression reduced mitochondrial respiration, despite lower extracellular Aβ levels compared to BACE overexpression. Surprisingly, this could be rescued by a gamma secretase inhibitor, oppositionally indicating an Aβ-mediated mitochondrial toxicity. Analyzing Aβ localization revealed that intracellular levels of Aβ and an increased spatial association of APP/Aβ with mitochondria are associated with reduced mitochondrial respiration. Thus, our data provide marked evidence for a prominent role of intracellular Aβ accumulation in Alzheimer´s disease associated mitochondrial dysfunction. Thereby it highlights the importance of the localization of APP processing and intracellular transport as a decisive factor for mitochondrial function, linking two prominent hallmarks of neurodegenerative diseases. PMID:28005987

Primary structure of the precursor for the anthozoan neuropeptide Antho-RFamide from Renilla köllikeri: Evidence for unusual processing enzymes

DEFF Research Database (Denmark)

Reinscheid, R K; Grimmelikhuijzen, C J

1994-01-01

distributed over the precursor protein. Of the 36 Antho-RFamide sequences, 29 copies are separated by the five amino acid spacer sequence Arg-Glu/Gly-Asn/Ser/Asp-Glu/Lys-Glu. This implicates processing at single Arg and single Glu residues. Endoproteolytic cleavage at the C-terminal side of paired or single......, and possibly also at other residues, and thus liberate all Antho-RFamide sequences. The processing of one precursor molecule probably yields 38 neuropeptides.(ABSTRACT TRUNCATED AT 250 WORDS)...... basic residues is a well known initial step in the maturation of precursor proteins. Cleavage at the C-terminal side of acidic residues, however, is unusual and must be catalyzed by a new type of processing enzyme. This processing enzyme is most likely to be an endoprotease, because the simplest way...

Process optimization for bioethanol production from cassava starch using novel eco-friendly enzymes

Energy Technology Data Exchange (ETDEWEB)

Shanavas, S.; Padmaja, G.; Moorthy, S.N.; Sajeev, M.S.; Sheriff, J.T. [Division of Crop Utilization, Central Tuber Crops Research Institute, Thiruvananthapuram, 695 017 Kerala (India)

2011-02-15

Although cassava (Manihot esculenta Crantz) is a potential bioethanol crop, high operational costs resulted in a negative energy balance in the earlier processes. The present study aimed at optimizing the bioethanol production from cassava starch using new enzymes like Spezyme {sup registered} Xtra and Stargen trademark 001. The liquefying enzyme Spezyme was optimally active at 90 C and pH 5.5 on a 10% (w/v) starch slurry at levels of 20.0 mg (280 Amylase Activity Units) for 30 min. Stargen levels of 100 mg (45.6 Granular Starch Hydrolyzing Units) were sufficient to almost completely hydrolyze 10% (w/v) starch at room temperature (30 {+-} 1 C). Ethanol yield and fermentation efficiency were very high (533 g/kg and 94.0% respectively) in the Stargen + yeast process with 10% (w/v) starch for 48 h. Raising Spezyme and Stargen levels to 560 AAU and 91.2 GSHU respectively for a two step loading [initial 20% (w/v) followed by 20% starch after Spezyme thinning]/initial higher loading of starch (40% w/v) resulted in poor fermentation efficiency. Upscaling experiments using 1.0 kg starch showed that Stargen to starch ratio of 1:100 (w/w) could yield around 558 g ethanol/kg starch, with a high fermentation efficiency of 98.4%. The study showed that Spezyme level beyond 20.0 mg for a 10% (w/v) starch slurry was not critical for optimizing bioethanol yield from cassava starch, although an initial thinning of starch for 30 min by Spezyme facilitated rapid saccharification-fermentation by Stargen + yeast system. The specific advantage of the new process was that the reaction could be completed within 48.5 h at 30 {+-} 1 C. (author)

Prediction of Wild-type Enzyme Characteristics

DEFF Research Database (Denmark)

Geertz-Hansen, Henrik Marcus

of biotechnology, including enzyme discovery and characterization. This work presents two articles on sequence-based discovery and functional annotation of enzymes in environmental samples, and two articles on analysis and prediction of enzyme thermostability and cofactor requirements. The first article presents...... a sequence-based approach to discovery of proteolytic enzymes in metagenomes obtained from the Polar oceans. We show that microorganisms living in these extreme environments of constant low temperature harbour genes encoding novel proteolytic enzymes with potential industrial relevance. The second article...... presents a web server for the processing and annotation of functional metagenomics sequencing data, tailored to meet the requirements of non-bioinformaticians. The third article presents analyses of the molecular determinants of enzyme thermostability, and a feature-based prediction method of the melting...

Utilization of cellulosic materials through enzymic hydrolysis. 11. Preliminary assessment of an integrated processing scheme

Energy Technology Data Exchange (ETDEWEB)

Wilke, C R; Cysewski, G R; Yang, R D

1976-01-01

An integrated processing scheme is described for the conversion of a cellulose waste (newsprint) to sugars by enzymic hydrolysis and then to ethanol and yeast by fermentation. The unconverted solids are burned to produce process energy requirements and surplus electric power. With the preliminary design at an estimate total capital investment of $33.4 x 10/sup 6/, 95% ethanol may be produced FOB (free on board) the plant for approx.61 cents/gal, assuming zero cost for cellulosic feed; taking into account interest rates and taxes and a cellulose feed cost of $20/ton the figure becomes $1.67/gal.

Regulations of enzymes in animals: effects of developmental processes, cancer, and radiation. Final report. [Analysis of enzymes in human cancer tissue

Energy Technology Data Exchange (ETDEWEB)

Knox, W.E.

1978-09-01

Low grade tumors of various origins are chemically very different. High grade tumors, whatever their origin, are chemically very similar to one another and to embryonic tissues. Analyses of human tumor tissues and sera from cancer patients were conducted for two new groups of enzymes expected to be informative about the physiological state of the tissue. The enzymes measured in tumors and sera were chosen because they were characteristic of fetal tissues and high grade neoplasms in rats, and could, therefore, be expected to exist in human cancers (and fetuses) and to predominate more in those of higher grade malignancies. Results indicated that the classification of enzymes (or isozymes) as fetal or adult types in the rat could be extended to man. Human cancers do contain most of the enzymes expected, and lack others, as expected. Analyses of the same enzymes in sera gave less clear results. It was recognized at the outset that no simple proportionality existed between tissue and serum levels. The tendency existed in cancer patients to have in serum elevated amounts of those enzymes characteristic of undifferentiated tissues. The abnormalities in a specific patient are conditioned by his physiological state, by the grade of his tumor, and by the mass of tumor present. The tumor mass had a very significant effect, so that monitoring this tumor burden by chemical means should be quite possible. The latest work focused on particular enzymes that have not previously been measured in cancer patients. These studies concentrated on pyrroline-5-carboxylate (P-5-C) reductase and its inhibition and on lysosomal glucosidases and phosphatases. Both groups are relatively high in fetal and neoplastic tissues.

Role of synthetic route on the transport properties of BaCe1-xYxO3 proton conductor

International Nuclear Information System (INIS)

Chiodelli, Gaetano; Malavasi, Lorenzo; Tealdi, Cristina; Barison, Simona; Battagliarin, Marino; Doubova, Lioudmila; Fabrizio, Monica; Mortalo, Cecilia; Gerbasi, Rosalba

2009-01-01

In this paper the role of the preparation route on the transport properties of the BaCe 1-x Y x O 3-δ solid solution with x = 0, 0.1, 0.15, and 0.2 has been studied. In particular, the samples were synthesized by means of the solid-state reaction and by a modified Pechini method. The effect of grain size on the sintering behaviour of the two samples batches was investigated by means of impedance spectroscopy and electron microscopy. It was found that a good sintering of the pellets can be achieved at 1250 deg. C for the samples prepared through the Pechini method. The ceramic route, even at higher temperatures, does not lead to good density values. The extensive conductivity measurements as a function of doping and gas environment (pure oxygen and argon + 10% H 2 + water) we carried out showed that the optimal Y-doping is around 15% and that a significant proton conductivity can be achieved for T lower than 500 deg. C. Above this temperature, the role of oxygen defects starts becoming relevant. Finally, the presence of a slope change in all the Arrhenius plots, irrespective to the gas environment, at about 450-500 deg. C was observed and qualitatively interpreted as due to a change in the nature of the main charge carriers involved

Enzyme-based solutions for textile processing and dye contaminant biodegradation-a review.

Science.gov (United States)

Chatha, Shahzad Ali Shahid; Asgher, Muhammad; Iqbal, Hafiz M N

2017-06-01

The textile industry, as recognized conformist and stake industry in the world's economy, is facing serious environmental challenges. In numerous industries, in practice, various chemical-based processes from initial sizing to final washing are fascinating harsh environment concerns. Some of these chemicals are corrosive to equipment and cause serious damage itself. Therefore, in the twenty-first century, chemical and allied industries quest a paradigm transition from traditional chemical-based concepts to a greener, sustainable, and environmentally friendlier catalytic alternative, both at the laboratory and industrial scales. Bio-based catalysis offers numerous benefits in the context of biotechnological industry and environmental applications. In recent years, bio-based processing has received particular interest among the scientist for inter- and multi-disciplinary investigations in the areas of natural and engineering sciences for the application in biotechnology sector at large and textile industries in particular. Different enzymatic processes such as chemical substitution have been developed or in the process of development for various textile wet processes. In this context, the present review article summarizes current developments and highlights those areas where environment-friendly enzymatic textile processing might play an increasingly important role in the textile industry. In the first part of the review, a special focus has been given to a comparative discussion of the chemical-based "classical/conventional" treatments and the modern enzyme-based treatment processes. Some relevant information is also reported to identify the major research gaps to be worked out in future.

Cerebrospinal fluid Aβ42 levels and APP processing pathway genes in Parkinson's disease.

Science.gov (United States)

Bekris, Lynn M; Tsuang, Debby W; Peskind, Elaine R; Yu, Chang E; Montine, Thomas J; Zhang, Jing; Zabetian, Cyrus P; Leverenz, James B

2015-06-01

Of recent interest is the finding that certain cerebrospinal fluid (CSF) biomarkers traditionally linked to Alzheimer's disease (AD), specifically amyloid beta protein (Aβ), are abnormal in PD CSF. The aim of this exploratory investigation was to determine whether genetic variation within the amyloid precursor protein (APP) processing pathway genes correlates with CSF Aβ42 levels in Parkinson's disease (PD). Parkinson's disease (n = 86) and control (n = 161) DNA were genotyped for 19 regulatory region tagging single-nucleotide polymorphisms (SNPs) within nine genes (APP, ADAM10, BACE1, BACE2, PSEN1, PSEN2, PEN2, NCSTN, and APH1B) involved in the cleavage of APP. The SNP genotypes were tested for their association with CSF biomarkers and PD risk while adjusting for age, sex, and APOE ɛ4 status. Significant correlation with CSF Aβ42 levels in PD was observed for two SNPs, (APP rs466448 and APH1B rs2068143). Conversely, significant correlation with CSF Aβ42 levels in controls was observed for three SNPs (APP rs214484, rs2040273, and PSEN1 rs362344). In addition, results of this exploratory investigation suggest that an APP SNP and an APH1B SNP are marginally associated with PD CSF Aβ42 levels in APOE ɛ4 noncarriers. Further hypotheses generated include that decreased CSF Aβ42 levels are in part driven by genetic variation in APP processing genes. Additional investigation into the relationship between these findings and clinical characteristics of PD, including cognitive impairment, compared with other neurodegenerative diseases, such as AD, are warranted. © 2015 International Parkinson and Movement Disorder Society. © 2015 International Parkinson and Movement Disorder Society.

Random-walk enzymes

Science.gov (United States)

Mak, Chi H.; Pham, Phuong; Afif, Samir A.; Goodman, Myron F.

2015-09-01

Enzymes that rely on random walk to search for substrate targets in a heterogeneously dispersed medium can leave behind complex spatial profiles of their catalyzed conversions. The catalytic signatures of these random-walk enzymes are the result of two coupled stochastic processes: scanning and catalysis. Here we develop analytical models to understand the conversion profiles produced by these enzymes, comparing an intrusive model, in which scanning and catalysis are tightly coupled, against a loosely coupled passive model. Diagrammatic theory and path-integral solutions of these models revealed clearly distinct predictions. Comparison to experimental data from catalyzed deaminations deposited on single-stranded DNA by the enzyme activation-induced deoxycytidine deaminase (AID) demonstrates that catalysis and diffusion are strongly intertwined, where the chemical conversions give rise to new stochastic trajectories that were absent if the substrate DNA was homogeneous. The C →U deamination profiles in both analytical predictions and experiments exhibit a strong contextual dependence, where the conversion rate of each target site is strongly contingent on the identities of other surrounding targets, with the intrusive model showing an excellent fit to the data. These methods can be applied to deduce sequence-dependent catalytic signatures of other DNA modification enzymes, with potential applications to cancer, gene regulation, and epigenetics.

Radioisotope-enzymes and cancer study

International Nuclear Information System (INIS)

Luyen, T. van

2008-01-01

Cancer is a pathological sign, when the abnormal cells appear in certain human tissues or organs. These cells can reproduce beyond the control of normal biological protection mechanism. Because they reproduce very fast, the metabolic process is accelerated, which causes the extreme need for more energy, substrate and catalyzing enzymes. Based on these needs, we can control the metabolic process by: Stopping supplying the energy. Stopping supplying the substrate and the materials to build up the cell's structure. Stopping operating catalysis by breaking out the enzyme's structure. Destroying the tumor cell by extra agents such as radiations and chemicals. All of these methods have been studied for a long time, which costs too much money, time and labor. Although we succeeded in some ways, the results are still not satisfactory. There are many reasons for this situation but the main one is the lack of information to understand all the processes taking place in the cell and our body. However, as far as we studied, we would like to propose the method to break the structure of the enzyme by nuclear decay process. (author)

Indicators: Sediment Enzymes

Science.gov (United States)

Sediment enzymes are proteins that are produced by microorganisms living in the sediment or soil. They are indicators of key ecosystem processes and can help determine which nutrients are affecting the biological community of a waterbody.

[Interaction between CYP450 enzymes and metabolism of traditional Chinese medicine as well as enzyme activity assay].

Science.gov (United States)

Lu, Tu-lin; Su, Lian-lin; Ji, De; Gu, Wei; Mao, Chun-qin

2015-09-01

Drugs are exogenous compounds for human bodies, and will be metabolized by many enzymes after administration. CYP450 enzyme, as a major metabolic enzyme, is an important phase I drug metabolizing enzyme. In human bodies, about 75% of drug metabolism is conducted by CYP450 enzymes, and CYP450 enzymes is the key factor for drug interactions between traditional Chinese medicine( TCM) -TCM, TCM-medicine and other drug combination. In order to make clear the interaction between metabolic enzymes and TCM metabolism, we generally chose the enzymatic activity as an evaluation index. That is to say, the enhancement or reduction of CYP450 enzyme activity was used to infer the inducing or inhibitory effect of active ingredients and extracts of traditional Chinese medicine on enzymes. At present, the common method for measuring metabolic enzyme activity is Cocktail probe drugs, and it is the key to select the suitable probe substrates. This is of great significance for study drug's absorption, distribution, metabolism and excretion (ADME) process in organisms. The study focuses on the interaction between TCMs, active ingredients, herbal extracts, cocktail probe substrates as well as CYP450 enzymes, in order to guide future studies.

Bioassay-Guided Isolated Compounds from Morinda officinalis Inhibit Alzheimer’s Disease Pathologies

Directory of Open Access Journals (Sweden)

Yoon Kyoung Lee

2017-09-01

Full Text Available Due to the side effects of synthetic drugs, the therapeutic potential of natural products for Alzheimer’s disease (AD has gained interest. Morinda officinalis has demonstrated inhibitory effects on geriatric diseases, such as bone loss and osteoporosis. However, although AD is a geriatric disease, M. officinalis has not been evaluated in an AD bioassay. Therefore, M. officinalis extracts and fractions were tested for AD-related activity, including inhibition of acetylcholinesterase (AChE, butyrylcholinesterase (BChE, β-site amyloid precursor protein cleaving enzyme 1 (BACE1, and advanced glycation end-product (AGE formation. A bioassay-guided approach led to isolation of 10 active compounds, eight anthraquinones (1–8, one coumarin (9, and one phytosterol (10, from n-hexane and ethyl acetate fractions of M. officinalis. The five anthraquinones (4–8 were stronger inhibitors of AChE than were other compounds. Compounds 3 and 9 were good inhibitors of BChE, and compounds 3 and 8 were good inhibitors of BACE1. Compounds 1–5 and 7–9 were more active than the positive control in inhibiting AGE formation. In addition, we first suggested a structure-activity relationship by which anthraquinones inhibit AChE and BACE1. Our findings demonstrate the preventive and therapeutic efficacy of M. officinalis for AD and its potential use as a natural alternative medicine.

Determining the safety of enzymes used in animal feed.

Science.gov (United States)

Pariza, Michael W; Cook, Mark

2010-04-01

The purpose of this paper is to provide guidance for evaluating the safety of enzyme preparations used in animal feed. Feed enzymes are typically added to animal feed to increase nutrient bioavailability by acting on feed components prior to or after consumption, i.e., within the gastrointestinal tract. In contrast, food processing enzymes are generally used during processing and then inactivated or removed prior to consumption. The enzymes used in both applications are almost always impure mixtures of active enzyme and other metabolites from the production strain, hence similar safety evaluation procedures for both are warranted. We propose that the primary consideration should be the safety of the production strain and that the decision tree mechanism developed previously for food processing enzymes (Pariza and Johnson, 2001) is appropriate for determining the safety of feed enzymes. Thoroughly characterized non-pathogenic, non-toxigenic microbial strains with a history of safe use in enzyme manufacture are also logical candidates for generating safe strain lineages, from which additional strains may be derived via genetic modification by traditional and non-traditional strategies. For new feed enzyme products derived from a safe strain lineage, it is important to ensure a sufficiently high safety margin for the intended use, and that the product complies with appropriate specifications for chemical and microbial contamination. Copyright 2009 Elsevier Inc. All rights reserved.

Biochemical characterization of thermostable cellulase enzyme from ...

African Journals Online (AJOL)

user

2012-05-29

May 29, 2012 ... tested for their ability to produce cellulase complex enzyme by growing on a defined substrates as well ... In the current industrial processes, cellulolytic enzymes ... energy sources such as glucose, ethanol, hydrogen and.

Improvement of phenolic antioxidants and quality characteristics of virgin olive oil with the addition of enzymes and nitrogen during olive paste processing

Energy Technology Data Exchange (ETDEWEB)

Inconomou, D.; Arapoglou, D.; Israilides, C.

2010-07-01

The evolution of phenolic compounds and their contribution to the quality characteristics in virgin olive oil during fruit processing was studied with the addition of a combination of various commercial enzymes containing pectinases, polygalacturonases, cellulase and {beta}-glucanase with or without nitrogen flush. Olive fruits (Olea europaea, L.) of the cultivar Megaritiki, at the semi black pigmentation stage of maturity, were used in a 3-phase extraction system in an experiment at industrial scale. The addition of enzymes in the olive paste during processing increased the total phenol and ortho-diphenol contents, as well as some simple phenolic compounds (3,4-DHPEA, p-HPEA) and the secoiridoid derivatives (3,4-DHPEA-EDA and 3,4-DHPEAEA) in olive oil and therefore improved its oxidative stability. Furthermore, enzyme treatment ameliorated the quality parameters of the produced olive oil (acidity and peroxide value) and their sensory attributes. The use of additional N{sub 2} flush with the enzyme treatments did not improve the quality parameters of olive oil any further; however it did not affect the concentration of individual and total sterols or most of the fatty acid composition. Consequently, olive paste treatment with enzymes not only improved the quality characteristics of olive oil and enhanced the overall organoleptic quality, but also increased the olive oil yield. (Author) 33 refs.

Evaluation of pressure tuning of enzymes

DEFF Research Database (Denmark)

Naghshineh, Mahsa

and high energy consumption. Therefore, searching for an environmentally friendly method of pectin extraction is a task for science and industry. Employment of hydrolytic enzymes may represent a green approach to obtain intact pectin polymer. However, the low stability/activity of enzymes, and low polymer...... yield of enzymatic extraction limits the application of enzyme in pectin production. There is evidence that emerging technology of high hydrostatic pressure processing can result in stabilization and activation of some enzymes. Therefore, the use of high hydrostatic pressure in combination with enzyme...... (cellulase/xylanase: 50/0, 50/25, 50/50, 25/50, and 0/50 U/g lime peel) at ambient pressure, 100 and 200 MPa were used to extract pectin from dried lime peel waste. It was found that pressure level, type and concentration of enzyme significantly influenced pectin yield and degree of esterification (DE...

Enzyme Engineering for In Situ Immobilization.

Science.gov (United States)

Rehm, Fabian B H; Chen, Shuxiong; Rehm, Bernd H A

2016-10-14

Enzymes are used as biocatalysts in a vast range of industrial applications. Immobilization of enzymes to solid supports or their self-assembly into insoluble particles enhances their applicability by strongly improving properties such as stability in changing environments, re-usability and applicability in continuous biocatalytic processes. The possibility of co-immobilizing various functionally related enzymes involved in multistep synthesis, conversion or degradation reactions enables the design of multifunctional biocatalyst with enhanced performance compared to their soluble counterparts. This review provides a brief overview of up-to-date in vitro immobilization strategies while focusing on recent advances in enzyme engineering towards in situ self-assembly into insoluble particles. In situ self-assembly approaches include the bioengineering of bacteria to abundantly form enzymatically active inclusion bodies such as enzyme inclusions or enzyme-coated polyhydroxyalkanoate granules. These one-step production strategies for immobilized enzymes avoid prefabrication of the carrier as well as chemical cross-linking or attachment to a support material while the controlled oriented display strongly enhances the fraction of accessible catalytic sites and hence functional enzymes.

Effects of 1950 MHz radiofrequency electromagnetic fields on Aβ processing in human neuroblastoma and mouse hippocampal neuronal cells

International Nuclear Information System (INIS)

Park, Jeongyeon; Kwon, Jong Hwa; Kim, Nam; Song, Kiwon

2018-01-01

Alzheimer’s disease (AD) is a neurodegenerative disease leading to progressive loss of memory and other cognitive functions. One of the well-known pathological markers of AD is the accumulation of amyloid-beta protein (Aβ), and its plaques, in the brain. Recent studies using Tg-5XFAD mice as a model of AD have reported that exposure to radiofrequency electromagnetic fields (RF-EMF) from cellular phones reduced Aβ plaques in the brain and showed beneficial effects on AD. In this study, we examined whether exposure to 1950 MHz RF-EMF affects Aβ processing in neural cells. We exposed HT22 mouse hippocampal neuronal cells and SH-SY5Y human neuroblastoma cells to RF-EMF (SAR 6 W/kg) for 2 h per day for 3 days, and analyzed the mRNA and protein expression of the key genes related to Aβ processing. When exposed to RF-EMF, mRNA levels of APP, BACE1, ADAM10 and PSEN1 were decreased in HT22, but the mRNA level of APP was not changed in SH-SY5Y cells. The protein expression of APP and BACE1, as well as the secreted Aβ peptide, was not significantly different between RF-EMF–exposed 7w-PSML, HT22 and SH-SY5Y cells and the unexposed controls. These observations suggest that RF-EMF exposure may not have a significant physiological effect on Aβ processing of neural cells in the short term. However, considering that we only exposed HT22 and SH-SY5Y cells to RF-EMF for 2 h per day for 3 days, we cannot exclude the possibility that 1950 MHz RF-EMF induces physiological change in Aβ processing with long-term and continuous exposure.

Enzymes of industrial purpose - review of the market of enzyme preparations and prospects for its development

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A. A. Tolkacheva

2017-01-01

Full Text Available Microbial enzyme preparations are increasingly replacing conventional chemical catalysts in a number of industrial processes. Such drugs, in addition to environmental friendliness and high activity, have a number of advantages over enzyme preparations of vegetable and animal origin, namely: the production of microbial enzymes in bioreactors is easily controlled and predictable; excreted microbiological enzymes are more stable than intracellular animals and plant enzymes; the genetic diversity of microorganisms makes it possible to produce enzyme preparations with a wide range of specificity; microbiological enzymes can be synthesized year-round, in contrast to the production of plant enzymes, which is often seasonal. The leaders of the world market of enzymes are proteases and amylases, which account for 25% and 15%, respectively. Over the past five years, the world market for carbohydrases, including mainly amylases, cellulases and xylanases, has been the fastest growing segment of the enzyme market with an aggregate annual growth rate of more than 7.0%. Another major product of the industrial enzyme market, which has a great potential for growth, is lipases. From the point of view of designation, the main part is represented by food and food enzymes. The Russian market continues to be unsaturated - the current supply is not able to meet the needs of the Russian feed and food industry in enzyme preparations. Enzyme preparations of domestic producers are in demand in forage production, while food industrial enterprises prefer imported products. The most significant enterprises in the enzymatic industry in Russia at the moment are Sibbiofarm, AgroSistema, Agroferment. In the light of the Russian policy of increasing food security, the development of the domestic enzyme industry is an extremely topical task.

Oxidative stress mediates the pathogenic effect of different Alzheimer's disease risk factors

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Michela Guglielmotto

2010-02-01

Full Text Available Alzheimer’s disease (AD is a progressive neurodegenerative disorder affecting the elderly population. Mechanistically, the major cause of the disease bases on the altered processing of the amyloid-β (Aβ precursor protein (APP, resulting in the accumulation and aggregation of neurotoxic forms of Aβ. Aβ derives from the sequential proteolytic cleavage of the β- and γ-secretases on APP. The causes of Aβ accumulation in the common sporadic form of Alzheimer’s disease are not completely known, but they are likely to include oxidative stress (OS. OS and Aβ are linked to each other since Aβ aggregation induces OS in vivo and in vitro, and oxidant agents increase the production of Aβ. Moreover, OS produces several effects that may contribute to synaptic function and cell death in AD. We and others have shown that the expression and activity of β-secretase (named BACE1; β-site APP cleaving enzyme is increased by oxidant agents and by lipid peroxidation product 4-hydroxynonenal and that there is a significant correlation between BACE1 activity and oxidative markers in sporadic AD. OS results from several cellular insults such as aging, hyperglycaemia, hypoxic insults that are all well known risk factors for AD development. Thus, our data strengthen the hypothesis that OS is a basic common pathway of Aβ accumulation, common to different AD risk factors.

Involvement of receptor tyrosine kinase Tyro3 in amyloidogenic APP processing and β-amyloid deposition in Alzheimer's disease models.

Directory of Open Access Journals (Sweden)

Yan Zheng

Full Text Available Alzheimer's disease (AD is the most common progressive neurodegenerative disease known to humankind. It is characterized by brain atrophy, extracellular amyloid plaques, and intracellular neurofibril tangles. β-Amyloid cascade is considered the major causative player in AD. Up until now, the mechanisms underlying the process of Aβ generation and accumulation in the brain have not been well understood. Tyro3 receptor belongs to the TAM receptor subfamily of receptor protein tyrosine kinases (RPTKs. It is specifically expressed in the neurons of the neocortex and hippocampus. In this study, we established a cell model stably expressing APPswe mutants and producing Aβ. We found that overexpression of Tyro3 receptor in the cell model significantly decreased Aβ generation and also down-regulated the expression of β-site amyloid precursor protein cleaving enzyme (BACE1. However, the effects of Tyro3 were inhibited by its natural ligand, Gas6, in a concentration-dependent manner. In order to confirm the role of Tyro3 in the progression of AD development, we generated an AD transgenic mouse model accompanied by Tyro3 knockdown. We observed a significant increase in the number of amyloid plaques in the hippocampus in the mouse model. More plaque-associated clusters of astroglia were also detected. The present study may help researchers determine the role of Tyro3 receptor in the neuropathology of AD.

Processing of Snake Venom Metalloproteinases: Generation of Toxin Diversity and Enzyme Inactivation

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Ana M. Moura-da-Silva

2016-06-01

Full Text Available Snake venom metalloproteinases (SVMPs are abundant in the venoms of vipers and rattlesnakes, playing important roles for the snake adaptation to different environments, and are related to most of the pathological effects of these venoms in human victims. The effectiveness of SVMPs is greatly due to their functional diversity, targeting important physiological proteins or receptors in different tissues and in the coagulation system. Functional diversity is often related to the genetic diversification of the snake venom. In this review, we discuss some published evidence that posit that processing and post-translational modifications are great contributors for the generation of functional diversity and for maintaining latency or inactivation of enzymes belonging to this relevant family of venom toxins.

Therapeutic Enzymes: Applications and Approaches to Pharmacological Improvement.

Science.gov (United States)

Yari, Maryam; Ghoshoon, Mohammad B; Vakili, Bahareh; Ghasemi, Younes

2017-01-01

Among therapeutic proteins, enzymes represent small and of course profitable market. They can be used to treat important, rare, and deadly diseases. Enzyme therapy is the only available treatment for certain disorders. Here, pharmaceutical enzymes are reviewed. They are categorized in four main groups, enzymes in replacement therapy, enzymes in cancer treatment, enzymes for fibrinolysis, and finally enzymes that are used topically for various treatments. Furthermore, enzyme gene therapy and future perspective of therapeutic enzymes are mentioned in brief. There are many important approved enzymes in pharmaceutical market. Several approaches such as point mutation, fusion protein designing, glycoengineering, and PEGylation were used to achieve improved enzymes. Although sometimes enzymes were engineered to facilitate production and purification process, appropriate delivery to target sites, extending half-life, and reducing immunogenicity are among the main goals of engineering approaches. Overall, enzymes play a critical role in treatment of common and rare diseases. Evaluation of new enzymes as well as improvement of approved enzymes are of the most important challenges in biotechnology. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Practical steady-state enzyme kinetics.

Science.gov (United States)

Lorsch, Jon R

2014-01-01

Enzymes are key components of most biological processes. Characterization of enzymes is therefore frequently required during the study of biological systems. Steady-state kinetics provides a simple and rapid means of assessing the substrate specificity of an enzyme. When combined with site-directed mutagenesis (see Site-Directed Mutagenesis), it can be used to probe the roles of particular amino acids in the enzyme in substrate recognition and catalysis. Effects of interaction partners and posttranslational modifications can also be assessed using steady-state kinetics. This overview explains the general principles of steady-state enzyme kinetics experiments in a practical, rather than theoretical, way. Any biochemistry textbook will have a section on the theory of Michaelis-Menten kinetics, including derivations of the relevant equations. No specific enzymatic assay is described here, although a method for monitoring product formation or substrate consumption over time (an assay) is required to perform the experiments described. © 2014 Elsevier Inc. All rights reserved.

Production of Biodiesel from High Acid Value Waste Cooking Oil Using an Optimized Lipase Enzyme/Acid-Catalyzed Hybrid Process

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N. Saifuddin

2009-01-01

Full Text Available The present study is aimed at developing an enzymatic/acid-catalyzed hybrid process for biodiesel production using waste cooking oil with high acid value (poor quality as feedstock. Tuned enzyme was prepared using a rapid drying technique of microwave dehydration (time required around 15 minutes. Further enhancement was achieved by three phase partitioning (TPP method. The results on the lipase enzyme which was subjected to pH tuning and TPP, indicated remarkable increase in the initial rate of transesterification by 3.8 times. Microwave irradiation was found to increase the initial reaction rates by further 1.6 times, hence giving a combined increase in activity of about 5.4 times. The optimized enzyme was used for hydrolysis and 88% of the oil taken initially was hydrolyzed by the lipase. The hydrolysate was further used in acid-catalyzed esterification for biodiesel production. By using a feedstock to methanol molar ratio of 1:15 and a sulphuric acid concentration of 2.5%, a biodiesel conversion of 88% was obtained at 50 °C for an hour reaction time. This hybrid process may open a way for biodiesel production using unrefined and used oil with high acid value as feedstock.

Enzyme Characterization in Microreactors by UV-Vis Spectroscopy

DEFF Research Database (Denmark)

Ringborg, Rolf Hoffmeyer; Krühne, Ulrich; Woodley, John

for selection can at this point be improved by characterization of the enzyme performance where also inhibition and toxicity effects are taken into account. Enzyme characterization is here defined as the effect on initial rate of reaction with respect to pH, enzyme, substrate, co-substrate, product and co......-product concentration [2]. From this investigation, it will be possible to determine whether the enzyme meets the criteria for process requirements or not. The development of the process will determine the requirements and this can also reach a state of maturity that resolves obstacles, lowers criteria and paves......, as the enzyme resource is scarce at this point of development. In the case where the reaction operates with UV active components, UV can be used to detect compounds with high sensitivity supplemented by multivariate data analysis. The spectra are here decorrelated and regressed to yield concentrations...

Modification of polymer surfaces to enhance enzyme activity and stability

DEFF Research Database (Denmark)

Hoffmann, Christian

Enzyme immobilization is an important concept for the development of improved biocatalytic processes, primarily through facilitated separation procedures. However, enzyme immobilization usually comes at a price of reduced biocatalytic activity. For this reason, different immobilization methods have...... already been developed, combining the same goal to improve enzyme activity, stability and selectivity. Polymer materials have shown, due to their easy processibility and versatile properties, high potential as enzyme support. However, in order to achieve improved enzyme performance, the combination...... on their tailored surface modification in order to obtain improved enzyme-support systems. Firstly, an off-stoichiometric thiol-ene (OSTE) thermosetting material was used for the development of a screening platform allowing the investigation of micro-environmental effects and their impact on the activity...

Matrix Metalloproteinase Enzyme Family

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Ozlem Goruroglu Ozturk

2013-04-01

Full Text Available Matrix metalloproteinases play an important role in many biological processes such as embriogenesis, tissue remodeling, wound healing, and angiogenesis, and in some pathological conditions such as atherosclerosis, arthritis and cancer. Currently, 24 genes have been identified in humans that encode different groups of matrix metalloproteinase enzymes. This review discuss the members of the matrix metalloproteinase family and their substrate specificity, structure, function and the regulation of their enzyme activity by tissue inhibitors. [Archives Medical Review Journal 2013; 22(2.000: 209-220

Enzymes: principles and biotechnological applications

Science.gov (United States)

Robinson, Peter K.

2015-01-01

Enzymes are biological catalysts (also known as biocatalysts) that speed up biochemical reactions in living organisms, and which can be extracted from cells and then used to catalyse a wide range of commercially important processes. This chapter covers the basic principles of enzymology, such as classification, structure, kinetics and inhibition, and also provides an overview of industrial applications. In addition, techniques for the purification of enzymes are discussed. PMID:26504249

A thermodynamic and theoretical view for enzyme regulation.

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Zhao, Qinyi

2015-01-01

Precise regulation is fundamental to the proper functioning of enzymes in a cell. Current opinions about this, such as allosteric regulation and dynamic contribution to enzyme regulation, are experimental models and substantially empirical. Here we proposed a theoretical and thermodynamic model of enzyme regulation. The main idea is that enzyme regulation is processed via the regulation of abundance of active conformation in the reaction buffer. The theoretical foundation, experimental evidence, and experimental criteria to test our model are discussed and reviewed. We conclude that basic principles of enzyme regulation are laws of protein thermodynamics and it can be analyzed using the concept of distribution curve of active conformations of enzymes.

The ultrasound technology for modifying enzyme activity

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Meliza Lindsay

2016-06-01

Full Text Available Enzymes are protein complexes compounds widely studied and used due to their ability to catalyze reactions. The food processing mainly aims the inactivation of enzymes due to various undesirable effects. However, there are many processes that can be optimized by its catalytic activity. In this context, different technologies have been applied both to inactivate or to improve the enzymes efficiency. The Ultrasound technology emerges as an alternative mainly applied to achieve the enzyme inactivation. On the contrary, very few investigations show the ability of this technology under certain conditions to achieve the opposite effect (i.e. increase the catalytic activity of enzymes. The objective of this study was to correlate the ultrasonic energy delivered to the sample (J/mL with the residual enzymatic activity and explain the possible mechanisms which results in the enzymatic activation/inactivation complex behavior. The activity of POD in coconut water was evaluated as a model. The enzymatic activity initially increased, followed by reduction with a trend to enzyme inactivation. This complex behavior is directly related to the applied ultrasonic energy and their direct mechanical effects on the product, as well as the effect in the enzymatic infinite intermediate states and its structural conformation changes. The obtained results are useful for both academic and industrial perspectives.

Watching Individual Enzymes at Work

Science.gov (United States)

Blank, Kerstin; Rocha, Susana; De Cremer, Gert; Roeffaers, Maarten B. J.; Uji-i, Hiroshi; Hofkens, Johan

Single-molecule fluorescence experiments are a powerful tool to analyze reaction mechanisms of enzymes. Because of their unique potential to detect heterogeneities in space and time, they have provided unprecedented insights into the nature and mechanisms of conformational changes related to the catalytic reaction. The most important finding from experiments with single enzymes is the generally observed phenomenon that the catalytic rate constants fluctuate over time (dynamic disorder). These fluctuations originate from conformational changes occurring on time scales, which are similar to or slower than that of the catalytic reaction. Here, we summarize experiments with enzymes that show dynamic disorder and introduce new experimental strategies showing how single-molecule fluorescence experiments can be applied to address other open questions in medical and industrial enzymology, such as enzyme inactivation processes, reactant transfer in cascade reactions, and the mechanisms of interfacial catalysis.

Magnetic cross-linked enzyme aggregates (CLEAs): a novel concept towards carrier free immobilization of lignocellulolytic enzymes.

Science.gov (United States)

Bhattacharya, Abhishek; Pletschke, Brett I

2014-01-01

The enzymatic conversion of lignocellulosic biomass into biofuels has been identified as an excellent strategy to generate clean energy. However, the current process is cost-intensive as an effective immobilization approach to reuse the enzyme(s) has been a major challenge. The present study introduces the concept and application of novel magnetic cross-linked enzyme aggregates (mag-CLEAs). Both mag-CLEAs and calcium-mag-CLEAs (Ca-mag-CLEAs) exhibited a 1.35 fold higher xylanase activity compared to the free enzyme and retained more than 80.0% and 90.0% activity, respectively, after 136h of incubation at 50°C, compared to 50% activity retained by CLEAs. A 7.4 and 9.0 fold higher sugar release from lime-pretreated and NH4OH pre-treated sugar bagasse, respectively, was achieved with Ca-mag-CLEAs compared to the free enzymes. The present study promotes the successful application of mag-CLEAs and Ca-mag-CLEAs as carrier free immobilized enzymes for the effective hydrolysis of lignocellulolytic biomass and associated biofuel feedstocks. Copyright © 2014 Elsevier Inc. All rights reserved.

Enzymes are a sweet way to do business

Energy Technology Data Exchange (ETDEWEB)

1980-01-04

The use of enzymes in industry is growing steadily. This artic discusses some areas of enzyme research: included are enzyme treatments for the production of high-fructose corn syrup and ethanol for gasohol blends, enzyme research focusing on cellulose breakdown, especially from municipal waste and pulp and paper waste to produce ethanol and the conversion of soybeans into a protein-rich powder. The enzymatic process for nitrogen fixation in the nodules of certain leguminous plants and in medical diagnostics are also mentioned.

Nuclear 82-kDa choline acetyltransferase decreases amyloidogenic APP metabolism in neurons from APP/PS1 transgenic mice.

Science.gov (United States)

Albers, Shawn; Inthathirath, Fatima; Gill, Sandeep K; Winick-Ng, Warren; Jaworski, Ewa; Wong, Daisy Y L; Gros, Robert; Rylett, R Jane

2014-09-01

Alzheimer disease (AD) is associated with increased amyloidogenic processing of amyloid precursor protein (APP) to β-amyloid peptides (Aβ), cholinergic neuron loss with decreased choline acetyltransferase (ChAT) activity, and cognitive dysfunction. Both 69-kDa ChAT and 82-kDa ChAT are expressed in cholinergic neurons in human brain and spinal cord with 82-kDa ChAT localized predominantly to neuronal nuclei, suggesting potential alternative functional roles for the enzyme. By gene microarray analysis, we found that 82-kDa ChAT-expressing IMR32 neural cells have altered expression of genes involved in diverse cellular functions. Importantly, genes for several proteins that regulate APP processing along amyloidogenic and non-amyloidogenic pathways are differentially expressed in 82-kDa ChAT-containing cells. The predicted net effect based on observed changes in expression patterns of these genes would be decreased amyloidogenic APP processing with decreased Aβ production. This functional outcome was verified experimentally as a significant decrease in BACE1 protein levels and activity and a concomitant reduction in the release of endogenous Aβ1-42 from neurons cultured from brains of AD-model APP/PS1 transgenic mice. The expression of 82-kDa ChAT in neurons increased levels of GGA3, which is involved in trafficking BACE1 to lysosomes for degradation. shRNA-induced decreases in GGA3 protein levels attenuated the 82-kDa ChAT-mediated decreases in BACE1 protein and activity and Aβ1-42 release. Evidence that 82-kDa ChAT can enhance GGA3 gene expression is shown by enhanced GGA3 gene promoter activity in SN56 neural cells expressing this ChAT protein. These studies indicate a novel relationship between cholinergic neurons and APP processing, with 82-kDa ChAT acting as a negative regulator of Aβ production. This decreased formation of Aβ could result in protection for cholinergic neurons, as well as protection of other cells in the vicinity that are sensitive to

Serine proteases as candidates for proteolytic processing of angiotensin-I converting enzyme.

Science.gov (United States)

Aragão, Danielle S; de Andrade, Maria Claudina C; Ebihara, Fabiana; Watanabe, Ingrid K M; Magalhães, Dayane C B P; Juliano, Maria Aparecida; Hirata, Izaura Yoshico; Casarini, Dulce Elena

2015-01-01

Somatic angiotensin-I converting enzyme (sACE) is a broadly distributed peptidase which plays a role in blood pressure and electrolyte homeostasis by the conversion of angiotensin I into angiotensin II. N-domain isoforms (nACE) with 65 and 90 kDa have been described in body fluids, tissues and mesangial cells (MC), and a 90 kDa nACE has been described only in spontaneously hypertensive rats. The aim of this study was to investigate the existence of proteolytic enzymes that may act in the hydrolysis of sACE generating nACEs in MC. After the confirmation of the presence of ACE sheddases in Immortalized MC (IMC), we purified and characterized these enzymes using fluorogenic substrates specifically designed for ACE sheddases. Purified enzyme identified as a serine protease by N-terminal sequence was able to generate nACE. In the present study, we described for the first time the presence of ACE sheddases in IMC, identified as serine proteases able to hydrolyze sACE in vitro. Further investigations are necessary to elucidate the mechanisms responsible for the expression and regulation of ACE sheddases in MC and their roles in the generation of nACEs, especially the 90 kDa form possibly related to hypertension. Copyright © 2014 Elsevier B.V. All rights reserved.

Microbial enzyme-catalyzed processes in soils and their analysis

Czech Academy of Sciences Publication Activity Database

Baldrian, Petr

2009-01-01

Roč. 55, č. 9 (2009), s. 370-378 ISSN 1214-1178 R&D Projects: GA MŠk LC06066; GA MŠk OC 155; GA MŠk OC08050; GA MZe QH72216 Institutional research plan: CEZ:AV0Z50200510 Keywords : assay methods * extracellular enzymes * ecology Subject RIV: EE - Microbiology, Virology Impact factor: 0.697, year: 2009

Enzyme

Science.gov (United States)

Enzymes are complex proteins that cause a specific chemical change in all parts of the body. For ... use them. Blood clotting is another example of enzymes at work. Enzymes are needed for all body ...

The ultrasound technology for modifying enzyme activity

Directory of Open Access Journals (Sweden)

Meliza Lindsay Rojas

2016-01-01

Full Text Available Enzymes are protein complexes compounds widely studied and used due to their ability to catalyze reactions. The food processing mainly a ims the inactivation of enzymes due to various undesirable effects. However, there are many processes that can be optimized by its catalytic activity. In this context, different technologies have been applied both to inactivate or to improve the enzymes ef ficiency. The Ultrasound technology emerges as an alternative mainly applied to achieve the enzyme inactivation. On the contrary, very few investigations show the ability of this technology under certain conditions to achieve the opposite effect (i.e. increase the catalytic activity of enzymes. The objective of this study was to correlate the ultrasonic energy delivered to the sample (J/mL with the residual enzymatic activity and explain the possible mechanisms which results in the enzymatic activation/in activation complex behavior. The activity of POD in coconut water was evaluated as a model. The enzymatic activity initially increased, followed by reduction with a trend to enzyme inactivation. This complex behavior is directly related to the applied ultr asonic energy and their direct mechanical effects on the product, as well as the effect in the enzymatic infinite intermediate states and its structural conformation changes. The obtained results are useful for both academic and industrial perspectives.

High throughput, high resolution enzymatic lithography process: effect of crystallite size, moisture, and enzyme concentration.

Science.gov (United States)

Mao, Zhantong; Ganesh, Manoj; Bucaro, Michael; Smolianski, Igor; Gross, Richard A; Lyons, Alan M

2014-12-08

By bringing enzymes into contact with predefined regions of a surface, a polymer film can be selectively degraded to form desired patterns that find a variety of applications in biotechnology and electronics. This so-called "enzymatic lithography" is an environmentally friendly process as it does not require actinic radiation or synthetic chemicals to develop the patterns. A significant challenge to using enzymatic lithography has been the need to restrict the mobility of the enzyme in order to maintain control of feature sizes. Previous approaches have resulted in low throughput and were limited to polymer films only a few nanometers thick. In this paper, we demonstrate an enzymatic lithography system based on Candida antartica lipase B (CALB) and poly(ε-caprolactone) (PCL) that can resolve fine-scale features, (<1 μm across) in thick (0.1-2.0 μm) polymer films. A Polymer Pen Lithography (PPL) tool was developed to deposit an aqueous solution of CALB onto a spin-cast PCL film. Immobilization of the enzyme on the polymer surface was monitored using fluorescence microscopy by labeling CALB with FITC. The crystallite size in the PCL films was systematically varied; small crystallites resulted in significantly faster etch rates (20 nm/min) and the ability to resolve smaller features (as fine as 1 μm). The effect of printing conditions and relative humidity during incubation is also presented. Patterns formed in the PCL film were transferred to an underlying copper foil demonstrating a "Green" approach to the fabrication of printed circuit boards.

Calsyntenin-1 shelters APP from proteolytic processing during anterograde axonal transport

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Martin Steuble

2012-06-01

Endocytosis of amyloid-β precursor protein (APP is thought to represent the major source of substrate for the production of the amyloidogenic Aβ peptide by the β-secretase BACE1. The irreversible nature of proteolytic cleavage implies the existence of an efficient replenishment route for APP from its sites of synthesis to the cell surface. We recently found that APP exits the trans-Golgi network in intimate association with calsyntenin-1, a transmembrane cargo-docking protein for Kinesin-1-mediated vesicular transport. Here we characterized the function of calsyntenin-1 in neuronal APP transport using selective immunoisolation of intracellular trafficking organelles, immunocytochemistry, live-imaging, and RNAi. We found that APP is co-transported with calsyntenin-1 along axons to early endosomes in the central region of growth cones in carriers that exclude the α-secretase ADAM10. Intriguingly, calsyntenin-1/APP organelles contained BACE1, suggesting premature cleavage of APP along its anterograde path. However, we found that APP contained in calsyntenin-1/APP organelles was stable. We further analyzed vesicular trafficking of APP in cultured hippocampal neurons, in which calsyntenin-1 was reduced by RNAi. We found a markedly increased co-localization of APP and ADAM10 in axons and growth cones, along with increased proteolytic processing of APP and Aβ secretion in these neurons. This suggested that the reduced capacity for calsyntenin-1-dependent APP transport resulted in mis-sorting of APP into additional axonal carriers and, therefore, the premature encounter of unprotected APP with its ectodomain proteases. In combination, our results characterize calsyntenin-1/APP organelles as carriers for sheltered anterograde axonal transport of APP.

Enzymes in biogenesis of plant cell wall polysaccharides. Enzyme characterization using tracer techniques

International Nuclear Information System (INIS)

Dickinson, D.B.

1975-01-01

Enzymes and metabolic pathways, by which starch and cell wall polysaccharides are formed, were investigated in order to learn how these processes are regulated and to identify the enzymatic regulatory mechanisms involved. Germinating lily pollen was used for studies of cell wall formation, and pollen and maize endosperm for studies of starch biosynthesis. Hexokinase being the first step in conversion of hexoses to starch, wall polysaccharides and respiratory substrates, maize endosperm enzyme was assayed by its conversion of 14 C-hexose to 14 C-hexose-6-P, and rapid separation of the two labelled compounds on anion-exchange paper. This enzyme did not appear to be under tight regulation by feed-back inhibition or activation, nor to be severely inhibited by glucose-6-P or activated by citrate. ADP-glucose pyrophosphorylase and other pyrophosphorylases were assayed radiochemically with 14 C-glucose-1-P (forward direction) or 32-PPsub(i) (reverse direction). They showed that the maize endosperm enzyme was activated by the glycolytic intermediates fructose-6-P and 3-phosphoglycerate, and that low levels of the enzyme were present in the high sucrose-low starch mutant named shrunken-2. Under optimal in-vitro assay conditions, the pollen enzyme reacted four times faster than the observed in-vivo rate of starch accumulation. Biogenesis of plant cell wall polysaccharides requires the conversion of hexose phosphates to various sugar nucleotides and utilization of the latter by the appropriate polysaccharide synthetases. Lily pollen possesses a β-1,3-glucan synthetase which is activated up to six-fold by β-linked oligosaccharides. Hence, the in-vivo activity of this enzyme may be modulated by such effector molecules

A model system for targeted drug release triggered by biomolecular signals logically processed through enzyme logic networks.

Science.gov (United States)

Mailloux, Shay; Halámek, Jan; Katz, Evgeny

2014-03-07

A new Sense-and-Act system was realized by the integration of a biocomputing system, performing analytical processes, with a signal-responsive electrode. A drug-mimicking release process was triggered by biomolecular signals processed by different logic networks, including three concatenated AND logic gates or a 3-input OR logic gate. Biocatalytically produced NADH, controlled by various combinations of input signals, was used to activate the electrochemical system. A biocatalytic electrode associated with signal-processing "biocomputing" systems was electrically connected to another electrode coated with a polymer film, which was dissolved upon the formation of negative potential releasing entrapped drug-mimicking species, an enzyme-antibody conjugate, operating as a model for targeted immune-delivery and consequent "prodrug" activation. The system offers great versatility for future applications in controlled drug release and personalized medicine.

Biocatalytic material comprising multilayer enzyme coated fiber

Science.gov (United States)

Kim, Jungbae [Richland, WA; Kwak, Ja Hun [Richland, WA; Grate, Jay W [West Richland, WA

2009-11-03

The present invention relates generally to high stability, high activity biocatalytic materials and processes for using the same. The materials comprise enzyme aggregate coatings having high biocatalytic activity and stability useful in heterogeneous environment. These new materials provide a new biocatalytic immobilized enzyme system with applications in bioconversion, bioremediation, biosensors, and biofuel cells.

Research Applications of Proteolytic Enzymes in Molecular Biology

OpenAIRE

Mótyán, János András; Tóth, Ferenc; Tőzsér, József

2013-01-01

Proteolytic enzymes (also termed peptidases, proteases and proteinases) are capable of hydrolyzing peptide bonds in proteins. They can be found in all living organisms, from viruses to animals and humans. Proteolytic enzymes have great medical and pharmaceutical importance due to their key role in biological processes and in the life-cycle of many pathogens. Proteases are extensively applied enzymes in several sectors of industry and biotechnology, furthermore, numerous research applications ...

Enzyme activity as an indicator of soil-rehabilitation processes at a zinc and lead ore mining and processing area.

Science.gov (United States)

Ciarkowska, Krystyna; Sołek-Podwika, Katarzyna; Wieczorek, Jerzy

2014-01-01

The activities of soil enzymes in relation to the changes occurring in the soil on a degraded area in southern Poland after zinc and lead mining were analyzed. An evaluation of the usefulness of urease and invertase activities for estimating the progress of the rehabilitation processes in degraded soil was performed. The data show that the soil samples differed significantly in organic carbon (0.68-104.0 g kg(-1)) and total nitrogen (0.03-8.64 g kg(-1)) content in their surface horizons. All of the soil samples (apart from one covered with forest) had very high total concentrations of zinc (4050-10,884 mg kg(-1)), lead (959-6661 mg kg(-1)) and cadmium (24.4-174.3 mg kg(-1)) in their surface horizons, and similar concentrations in their deeper horizons. Nevertheless, the amounts of the soluble forms of the above-mentioned heavy metals were quite low and they accounted for only a small percentage of the total concentrations: 1.4% for Zn, 0.01% for Pb and 2.6% for Cd. Urease activities were ranked as follows: soil from flotation settler (0.88-1.78 μg N-NH4(+) 2h(-1) g(-1))slag heaps (1.77-2.51 μg N-NH4(+) 2h(-1) g(-1))slag heaps, ranging from 20.5 to 77.1mg of the inverted sugar, but they were much lower in soil from the flotation settler (0.12-6.95 mg of the inverted sugar). The results demonstrated that heavy pollution with Zn, Pb and Cd slightly decreased the activities of urease and invertase. It is thought that it resulted from the enzyme reactions occurring in slightly acidic or alkaline soil conditions. Under such conditions, heavy metals occur mainly in insoluble forms. The activities of these enzymes are strongly dependent on the content and decomposition of organic matter in the soil. Copyright © 2013 Elsevier Ltd. All rights reserved.

Database of ligand-induced domain movements in enzymes

Directory of Open Access Journals (Sweden)

Hayward Steven

2009-03-01

Full Text Available Abstract Background Conformational change induced by the binding of a substrate or coenzyme is a poorly understood stage in the process of enzyme catalysed reactions. For enzymes that exhibit a domain movement, the conformational change can be clearly characterized and therefore the opportunity exists to gain an understanding of the mechanisms involved. The development of the non-redundant database of protein domain movements contains examples of ligand-induced domain movements in enzymes, but this valuable data has remained unexploited. Description The domain movements in the non-redundant database of protein domain movements are those found by applying the DynDom program to pairs of crystallographic structures contained in Protein Data Bank files. For each pair of structures cross-checking ligands in their Protein Data Bank files with the KEGG-LIGAND database and using methods that search for ligands that contact the enzyme in one conformation but not the other, the non-redundant database of protein domain movements was refined down to a set of 203 enzymes where a domain movement is apparently triggered by the binding of a functional ligand. For these cases, ligand binding information, including hydrogen bonds and salt-bridges between the ligand and specific residues on the enzyme is presented in the context of dynamical information such as the regions that form the dynamic domains, the hinge bending residues, and the hinge axes. Conclusion The presentation at a single website of data on interactions between a ligand and specific residues on the enzyme alongside data on the movement that these interactions induce, should lead to new insights into the mechanisms of these enzymes in particular, and help in trying to understand the general process of ligand-induced domain closure in enzymes. The website can be found at: http://www.cmp.uea.ac.uk/dyndom/enzymeList.do

Recycle of enzymes and substrate following enzymatic hydrolysis of steam-pretreated aspenwood

Energy Technology Data Exchange (ETDEWEB)

Mes-Hartree, M.; Hogan, C.M.; Saddler, J.N.

1987-09-01

The commercial production of chemicals and fuels from lignocellulosic residues by enzymatic means still requires considerable research on both the technical and economic aspects. Two technical problems that have been identified as requiring further research are the recycle of the enzymes used in hydrolysis and the reuse of the recalcitrant cellulose remaining after incomplete hydrolysis. Enzyme recycle is required to lower the cost of the enzymes, while the reuse of the spent cellulose will lower the feedstock cost. The conversion process studied was a combined enzymatic hydrolysis and fermentation (CHF) procedure that utilized the cellulolytic enzymes derived from the fungus Trichoderma harzianum E58 and the yeast Saccharomyces cerevisiae. The rate and extent of hydrolysis and ethanol production was monitored as was the activity and hydrolytic potential of the enzymes remaining in the filtrate after the hydrolysis period. When a commercial cellulose was used as the substrate for a routine 2-day CHF process, 60% of the original filter paper activity could be recovered. When steam-treated, water-extracted aspenwood was used as the substrate, only 13% of the original filter paper activity was detected after a similar procedure. The combination of 60% spent enzymes with 40% fresh enzymes resulted in the production of 30% less reducing sugars than the original enzyme mixture. Since 100% hydrolysis of the cellulose portion is seldom accomplished in an enzymatic hydrolysis process, the residual cellulose was used as a substrate for the growth of T. harzianum E58 and production of cellulolytic enzymes. The residue remaining after the CHF process was used as a substrate for the production of the cellulolytic enzymes. The production of enzymes from the residue of the Solka Floc hydrolysis was greater than the production of enzymes from the original Solka Floc. (Refs. 14).

Effect of Bacillus cereus Enzymes on Milk Quality following Ultra High Temperature Processing

Directory of Open Access Journals (Sweden)

B. Janštová

2006-01-01

Full Text Available Using a model case of contamination of long-life semi-skimmed milk with the spores of six B. cereus strains, isolated from the farm environment and raw milk, proteolysis was monitored by measuring changes in protein content by infra-red spectroscopy; free tyrosine was measured by the Lowry method according to Juffs, and the reduction in casein fractions by SDS-PAGE. Lipolysis was monitored by the dilution extractive method. At a storage temperature of 4 °C for 4 months no enzyme processes were observed, whereas at a storage temperature of 24 °C a marked enzyme activity was found during maximum 3 weeks as well as sensory changes of UHT milk. After three weeks of storage, a reduction in protein content from 34.55 g l-1 milk to 29.46 ± 2.00 g l-1 milk, and a reduction in the free tyrosine from 0.65 to 2.13 ± 0.28 mg ml-1 was found, as well as increased molar contents of free fatty acids (FFA from 41.97 to 1617.22 ± 68.17 mmol kg-1 milk fat. After six days of storage, α-casein, β-casein and κ-casein dropped to 69 ± 10%, 56 ± 16% and 43 ± 10%, respectively. Majority of changes in UHT milk depended on the B. cereus strain used, initial microbial counts and the method of heat inactivation of spores.

Enzymic hydrolysis of cellulosic wastes to glucose

Energy Technology Data Exchange (ETDEWEB)

Spano, L A; Medeiros, J; Mandels, M

1976-01-01

An enzymic process for the conversion of cellulose to glucose is based on the use of a specific enzyme derived from mutant strains of the fungus trichoderma viride which is capable of reacting with the crystalline fraction of the cellulose molecule. The production and mode of action of the cellulase complex produced during the growth of trichoderma viride is discussed as well as the application of such enzymes for the conversion of cellulosic wastes to crude glucose syrup for use in production of chemical feedstocks, single-cell proteins, fuels, solvents, etc.

Immobilized enzyme reactor chromatography: Optimization of protein retention and enzyme activity in monolithic silica stationary phases

International Nuclear Information System (INIS)

Besanger, Travis R.; Hodgson, Richard J.; Green, James R.A.; Brennan, John D.

2006-01-01

Our group recently reported on the application of protein-doped monolithic silica columns for immobilized enzyme reactor chromatography, which allowed screening of enzyme inhibitors present in mixtures using mass spectrometry for detection. The enzyme was immobilized by entrapment within a bimodal meso/macroporous silica material prepared by a biocompatible sol-gel processing route. While such columns proved to be useful for applications such as screening of protein-ligand interactions, significant amounts of entrapped proteins leached from the columns owing to the high proportion of macropores within the materials. Herein, we describe a detailed study of factors affecting the morphology of protein-doped bioaffinity columns and demonstrate that specific pH values and concentrations of poly(ethylene glycol) can be used to prepare essentially mesoporous columns that retain over 80% of initially loaded enzyme in an active and accessible form and yet still retain sufficient porosity to allow pressure-driven flow in the low μL/min range. Using the enzyme γ-glutamyl transpeptidase (γ-GT), we further evaluated the catalytic constants of the enzyme entrapped in capillary columns with different silica morphologies as a function of flowrate and backpressure using the enzyme reactor assay mode. It was found that the apparent activity of the enzyme was highest in mesoporous columns that retained high levels of enzyme. In such columns, enzyme activity increased by ∼2-fold with increases in both flowrate (from 250 to 1000 nL/min) and backpressure generated (from 500 to 2100 psi) during the chromatographic activity assay owing to increases in k cat and decreases in K M , switching from diffusion controlled to reaction controlled conditions at ca. 2000 psi. These results suggest that columns with minimal macropore volumes (<5%) are advantageous for the entrapment of soluble proteins for bioaffinity and bioreactor chromatography

Enzyme Informatics

Science.gov (United States)

Alderson, Rosanna G.; Ferrari, Luna De; Mavridis, Lazaros; McDonagh, James L.; Mitchell, John B. O.; Nath, Neetika

2012-01-01

Over the last 50 years, sequencing, structural biology and bioinformatics have completely revolutionised biomolecular science, with millions of sequences and tens of thousands of three dimensional structures becoming available. The bioinformatics of enzymes is well served by, mostly free, online databases. BRENDA describes the chemistry, substrate specificity, kinetics, preparation and biological sources of enzymes, while KEGG is valuable for understanding enzymes and metabolic pathways. EzCatDB, SFLD and MACiE are key repositories for data on the chemical mechanisms by which enzymes operate. At the current rate of genome sequencing and manual annotation, human curation will never finish the functional annotation of the ever-expanding list of known enzymes. Hence there is an increasing need for automated annotation, though it is not yet widespread for enzyme data. In contrast, functional ontologies such as the Gene Ontology already profit from automation. Despite our growing understanding of enzyme structure and dynamics, we are only beginning to be able to design novel enzymes. One can now begin to trace the functional evolution of enzymes using phylogenetics. The ability of enzymes to perform secondary functions, albeit relatively inefficiently, gives clues as to how enzyme function evolves. Substrate promiscuity in enzymes is one example of imperfect specificity in protein-ligand interactions. Similarly, most drugs bind to more than one protein target. This may sometimes result in helpful polypharmacology as a drug modulates plural targets, but also often leads to adverse side-effects. Many cheminformatics approaches can be used to model the interactions between druglike molecules and proteins in silico. We can even use quantum chemical techniques like DFT and QM/MM to compute the structural and energetic course of enzyme catalysed chemical reaction mechanisms, including a full description of bond making and breaking. PMID:23116471

Production of amylase enzyme from mangrove fungal isolates ...

African Journals Online (AJOL)

The mangrove ecosystem serves as a bioresource for various industrially important microorganisms. The use of fungi as a source of industrially relevant enzymes led to an increased interest in the application of microbial enzymes in various industrial processes. Fungal colonies were isolated from sediments of five different ...

Copper stressed anaerobic fermentation: biogas properties, process stability, biodegradation and enzyme responses.

Science.gov (United States)

Hao, He; Tian, Yonglan; Zhang, Huayong; Chai, Yang

2017-12-01

The effect of copper (added as CuCl 2 ) on the anaerobic co-digestion of Phragmites straw and cow dung was studied in pilot experiments by investigating the biogas properties, process stability, substrate degradation and enzyme activities at different stages of mesophilic fermentation. The results showed that 30 and 100 mg/L Cu 2+ addition increased the cumulative biogas yields by up to 43.62 and 20.77% respectively, and brought forward the daily biogas yield peak, while 500 mg/L Cu 2+ addition inhibited biogas production. Meanwhile, the CH 4 content in the 30 and 100 mg/L Cu 2+ -added groups was higher than that in the control group. Higher pH values (close to pH 7) and lower oxidation-reduction potential (ORP) values in the Cu 2+ -added groups after the 8th day indicated better process stability compared to the control group. In the presence of Cu 2+ , the degradation of volatile fatty acids (VFAs) and other organic molecules (represented by chemical oxygen demand, COD) generated from hydrolysis was enhanced, and the ammonia nitrogen (NH 4 + -N) concentrations were more stable than in the control group. The contents of lignin and hemicellulose in the substrate declined in the Cu 2+ -added groups while the cellulose contents did not. Neither the cellulase nor the coenzyme F 420 activities could determine the biogas producing efficiency. Taking the whole fermentation process into account, the promoting effect of Cu 2+ addition on biogas yields was mainly attributable to better process stability, the enhanced degradation of lignin and hemicellulose, the transformation of intermediates into VFA, and the generation of CH 4 from VFA.

Discovery of enzymes for toluene synthesis from anoxic microbial communities

DEFF Research Database (Denmark)

Beller, Harry R.; Rodrigues, Andria V.; Zargar, Kamrun

2018-01-01

Microbial toluene biosynthesis was reported in anoxic lake sediments more than three decades ago, but the enzyme catalyzing this biochemically challenging reaction has never been identified. Here we report the toluene-producing enzyme PhdB, a glycyl radical enzyme of bacterial origin that catalyzes...... phenylacetate decarboxylation, and its cognate activating enzyme PhdA, a radical S-adenosylmethionine enzyme, discovered in two distinct anoxic microbial communities that produce toluene. The unconventional process of enzyme discovery from a complex microbial community (>300,000 genes), rather than from...... a microbial isolate, involved metagenomics- and metaproteomics-enabled biochemistry, as well as in vitro confirmation of activity with recombinant enzymes. This work expands the known catalytic range of glycyl radical enzymes (only seven reaction types had been characterized previously) and aromatic...

Archaeal Enzymes and Applications in Industrial Biocatalysts.

Science.gov (United States)

Littlechild, Jennifer A

2015-01-01

Archaeal enzymes are playing an important role in industrial biotechnology. Many representatives of organisms living in "extreme" conditions, the so-called Extremophiles, belong to the archaeal kingdom of life. This paper will review studies carried by the Exeter group and others regarding archaeal enzymes that have important applications in commercial biocatalysis. Some of these biocatalysts are already being used in large scale industrial processes for the production of optically pure drug intermediates and amino acids and their analogues. Other enzymes have been characterised at laboratory scale regarding their substrate specificity and properties for potential industrial application. The increasing availability of DNA sequences from new archaeal species and metagenomes will provide a continuing resource to identify new enzymes of commercial interest using both bioinformatics and screening approaches.

Evaluation of the efficiency of alternative enzyme production technologies

DEFF Research Database (Denmark)

Albæk, Mads Orla

Enzymes are used in an increasing number of industries. The application of enzymes is extending into the production of lignocellulosic ethanol in processes that economically can compete with fossil fuels. Since lignocellulosic ethanol is based on renewable resources it will have a positive impact...... production of cellulases and hemi-cellulases. The aim of the thesiswas to use modeling tools to identify alternative technologies that have higher energy or raw material efficiency than the current technology. The enzyme production by T. reesei was conducted as an aerobic fed-batch fermentation. The process...... of the uncertainty and sensitivity of the model indicated the biological parameters to be responsible for most of the model uncertainty. A number of alternative fermentation technologies for enzyme production were identified in the open literature. Their mass transfer capabilities and their energy efficiencies were...

Technological advances and applications of hydrolytic enzymes for valorization of lignocellulosic biomass.

Science.gov (United States)

Manisha; Yadav, Sudesh Kumar

2017-12-01

Hydrolytic enzymes are indispensable tools in the production of various foodstuffs, drugs, and consumables owing to their applications in almost every industrial process nowadays. One of the foremost areas of interest involving the use of hydrolytic enzymes is in the transformation of lignocellulosic biomass into value added products. However, limitations of the processes due to inadequate enzyme activity and stability with a narrow range of pH and temperature optima often limit their effective usage. The innovative technologies, involving manipulation of enzyme activity and stability through mutagenesis, genetic engineering and metagenomics lead to a major leap in all the fields using hydrolytic enzymes. This article provides recent advancement towards the isolation and use of microbes for lignocellulosic biomass utilisation, microbes producing the hydrolytic enzymes, the modern age technologies used to manipulate and enhance the hydrolytic enzyme activity and the applications of such enzymes in value added products development from lignocellulosic biomass. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microbial genetic engineering and enzyme technology

Energy Technology Data Exchange (ETDEWEB)

Hollenberg, C.P.; Sahm, H.

1987-01-01

In a series of up-to-date contributions BIOTEC 1 has experts discussing the current topics in microbial gene technology and enzyme technology and speculating on future developments. Bacterial and yeast systems for the production of interferons, growth hormone or viral antigenes are described as well as the impact of gene technology on plants. Exciting is the prospect of degrading toxic compounds in our environment by microorganisms tuned in the laboratory. Enzymes are the most effective catalysts we know. They exhibit a very high substrate- and stereospecificity. These properties make enzymes extremely attractive as industrial catalysts, leading to new production processes that are non-polluting and save both energy and raw materials. (orig.) With 135 figs., 36 tabs.

The N-glycan processing enzymes α-mannosidase and β-D-N-acetylhexosaminidase are involved in ripening-associated softening in the non-climacteric fruits of capsicum

Science.gov (United States)

Ghosh, Sumit; Meli, Vijaykumar S.; Kumar, Anil; Thakur, Archana; Chakraborty, Niranjan; Chakraborty, Subhra; Datta, Asis

2011-01-01

Excessive softening of fruits during the ripening process leads to deterioration. This is of significant global importance as softening-mediated deterioration leads to huge postharvest losses. N-glycan processing enzymes are reported to play an important role during climacteric fruit softening: however, to date these enzymes have not been characterized in non-climacteric fruit. Two ripening-specific N-glycan processing enzymes, α-mannosidase (α-Man) and β-D-N-acetylhexosaminidase (β-Hex), have been identified and targeted to enhance the shelf life in non-climacteric fruits such as capsicum (Capsicum annuum). The purification, cloning, and functional characterization of α-Man and β-Hex from capsicum, which belong to glycosyl hydrolase (GH) families 38 and 20, respectively, are described here. α-Man and β-Hex are cell wall glycoproteins that are able to cleave terminal α-mannose and β-D-N-acetylglucosamine residues of N-glycans, respectively. α-Man and β-Hex transcripts as well as enzyme activity increase with the ripening and/or softening of capsicum. The function of α-Man and β-Hex in capsicum softening is investigated through RNA interference (RNAi) in fruits. α-Man and β-Hex RNAi fruits were approximately two times firmer compared with the control and fruit deterioration was delayed by approximately 7 d. It is shown that silencing of α-Man and β-Hex enhances fruit shelf life due to the reduced degradation of N-glycoproteins which resulted in delayed softening. Altogether, the results provide evidence for the involvement of N-glycan processing in non-climacteric fruit softening. In conclusion, genetic engineering of N-glycan processing can be a common strategy in both climacteric and non-climacteric species to reduce the post-harvest crop losses. PMID:21030387

Enzyme loading dependence of cellulose hydrolysis of sugarcane bagasse

Directory of Open Access Journals (Sweden)

Carlos Martín

2012-01-01

Full Text Available The enzymatic hydrolysis of steam-pretreated sugarcane bagasse, either delignified or non-delignified, was studied as a function of enzyme loading. Hydrolysis experiments were carried out using five enzyme loadings (2.5 to 20 FPU/g cellulose and the concentration of solids was 2% for both materials. Alkaline delignification improved cellulose hydrolysis by increasing surface area. For both materials, glucose concentrations increased with enzyme loading. On the other hand, enzyme loadings higher than 15 FPU/g did not result in any increase in the initial rate, since the excess of enzyme adsorbed onto the substrate restricted the diffusion process through the structure.

Kinetics of leather dyeing pretreated with enzymes: role of acid protease.

Science.gov (United States)

Kanth, Swarna Vinodh; Venba, Rajangam; Jayakumar, Gladstone Christopher; Chandrababu, Narasimhan Kannan

2009-04-01

In the present investigation, kinetics of dyeing involving pretreatment with acid protease has been presented. Application of acid protease in dyeing process resulted in increased absorption and diffusion of dye into the leather matrix. Enzyme treatment at 1% concentration, 60 min duration and 50 degrees C resulted in maximum of 98% dye exhaustion and increased absorption rate constants. The final exhaustion (C(infinity)) for the best fit of CI Acid Black 194 dye has been 98.5% with K and r2 values from the modified Cegarra-Puente isotherm as 0.1033 and 0.0631. CI Acid Black 194 being a 2:1 metal complex acid dye exhibited higher absorption rate than the acid dye CI Acid Black 210. A reduction in 50% activation energy calculated from Arrhenius equation has been observed in enzyme assisted dyeing process of both the dyes that substantiates enhanced dye absorption. The absorption rate constant calculated with modified Cegarra-Puente equation confirm higher rate constants and faster kinetics for enzyme assisted dyeing process. Enzyme treated leather exhibited richness of color and shade when compared with control. The present study substantiates the essential role of enzyme pretreatment as an eco-friendly leather dyeing process.

Enzyme Technology for Shipboard Waste Management

Science.gov (United States)

1976-12-01

sucrose to the sweeter invert sugar by the enzyme invertase is a well established process, as is the conversion of starch to glucose by the enzyme...aspects of our health and daily lives. Recent advances in fundamental and applied enzymology indicate that we have already started in that direction. At a...Chemtech, p. 677 (Nov 1973) 11 - Bungay, H. P., "Applied Enzymology ," Worthington, Biochemical Corp., Notes for an AIChE Lecture, Washington, D. C. (Dec

Structural similarities and functional differences clarify evolutionary relationships between tRNA healing enzymes and the myelin enzyme CNPase.

Science.gov (United States)

Muruganandam, Gopinath; Raasakka, Arne; Myllykoski, Matti; Kursula, Inari; Kursula, Petri

2017-05-16

Eukaryotic tRNA splicing is an essential process in the transformation of a primary tRNA transcript into a mature functional tRNA molecule. 5'-phosphate ligation involves two steps: a healing reaction catalyzed by polynucleotide kinase (PNK) in association with cyclic phosphodiesterase (CPDase), and a sealing reaction catalyzed by an RNA ligase. The enzymes that catalyze tRNA healing in yeast and higher eukaryotes are homologous to the members of the 2H phosphoesterase superfamily, in particular to the vertebrate myelin enzyme 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase). We employed different biophysical and biochemical methods to elucidate the overall structural and functional features of the tRNA healing enzymes yeast Trl1 PNK/CPDase and lancelet PNK/CPDase and compared them with vertebrate CNPase. The yeast and the lancelet enzymes have cyclic phosphodiesterase and polynucleotide kinase activity, while vertebrate CNPase lacks PNK activity. In addition, we also show that the healing enzymes are structurally similar to the vertebrate CNPase by applying synchrotron radiation circular dichroism spectroscopy and small-angle X-ray scattering. We provide a structural analysis of the tRNA healing enzyme PNK and CPDase domains together. Our results support evolution of vertebrate CNPase from tRNA healing enzymes with a loss of function at its N-terminal PNK-like domain.

Stable, easily sintered BaCe0.5Zr0.3Y0.16Zn0.04O3-δ electrolyte-based proton-conducting solid oxide fuel cells by gel-casting and suspension spray

International Nuclear Information System (INIS)

Lin Bin; Dong Yingchao; Wang Songlin; Fang Daru; Ding Hanping; Zhang Xiaozhen; Liu Xingqin; Meng Guangyao

2009-01-01

Protonic ceramic membrane fuel cells (PCMFCs) based on oxide proton conductors exhibit more advantages than traditional solid oxide fuel cells (SOFCs) based on oxygen-ion conducting electrolytes, such as low activation energy and high energy efficiency. In order to develop a simple and cost-effective route to fabricate PCMFCs with SrCo 0.9 Sb 0.1 O 3-δ (SCS) cubic perovskite cathode, a dense BaCe 0.5 Zr 0.3 Y 0.16 Zn 0.04 O 3-δ (BCZYZn) electrolyte was fabricated in situ metal oxide on a porous anode support by gel-casting and suspension spray, which is cost-effective, easy to realize, and suitable for mass-production. The key part of this process is to directly spray well-mixed suspension of BaCO 3 , CeO 2 , ZrO 2 , Y 2 O 3 and ZnO instead of pre-synthesized BCZYZn ceramic powder on the anode substrate. With SCS cubic perovskite cathode synthesized by gel-casting on the bi-layer, single cells were assembled and tested with H 2 as fuel and the static air as oxidant. An open-circuit potential of 0.987 V, a maximum power density of 364 mW cm -2 , and a low polarization resistance of the electrodes of 0.07 Ω cm 2 was achieved at 700 deg. C.

A sensitive enzyme-linked immunosorbent assay for the determination of fish protein in processed foods.

Science.gov (United States)

Shibahara, Yusuke; Uesaka, Yoshihiko; Wang, Jun; Yamada, Shoichi; Shiomi, Kazuo

2013-01-15

Fish is one of the most common causes of food allergy and its major allergen is parvalbumin, a 12 kDa muscular protein. In this study, a sandwich enzyme-linked immunosorbent assay (ELISA) for the determination of fish protein in processed foods was developed using a polyclonal antibody raised against Pacific mackerel parvalbumin. The developed sandwich ELISA showed 22.6-99.0% reactivity (based on the reactivity to Pacific mackerel parvalbumin) to parvalbumins from various species of fish. The limits of detection and quantitation were estimated to be 0.23 and 0.70 μg protein per g of food, respectively. When the sandwich ELISA was subjected to inter-laboratory validation, spiked fish protein was recovered from five model processed foods in the range of 69.4-84.8% and the repeatability and reproducibility relative standard deviations were satisfactorily low (≤ 10.5%). Thus, the sandwich ELISA was judged to be a useful tool to determine fish protein in processed foods. Copyright © 2012 Elsevier Ltd. All rights reserved.

Study of cellulase enzymes self-assembly in aqueous-acetonitrile solvent: Viscosity measurements

Energy Technology Data Exchange (ETDEWEB)

Ghaouar, N., E-mail: naoufel-ghaouar@lycos.co [Laboratoire de Physique de la Matiere Molle, Faculte des Sciences de Tunis, Campus Universitaire, 2092 (Tunisia); Institut National des Sciences Appliquees et de Technologie, INSAT, Centre Urbain Nord, BP. 676, Tunis (Tunisia); Aschi, A. [Laboratoire de Physique de la Matiere Molle, Faculte des Sciences de Tunis, Campus Universitaire, 2092 (Tunisia); Belbahri, L. [School of Engineering of Lullier, University of Applied Sciences of Western Switzerland, 150, Route de Presinge, 1254 Jussy (Switzerland); Trabelsi, S.; Gharbi, A. [Laboratoire de Physique de la Matiere Molle, Faculte des Sciences de Tunis, Campus Universitaire, 2092 (Tunisia)

2009-11-15

The present study extends the viscosity measurements performed by Ghaouar et al. [Physica B, submitted for publication.] to study the conformational change of the cellulase enzymes in aqueous-acetonitrile mixture. We aim to investigate: (i) the denaturation process by measuring the specific viscosity for temperatures varying between 25 and 65 deg. C and acetonitrile concentrations between 0% and 50%, (ii) the enzyme-enzyme interaction by calculating the Huggins coefficient and (iii) the enzyme sizes by following the hydrodynamic radius for various temperatures. The precipitation of cellulases versus acetonitrile concentration is also considered. We show from all physical quantities measured in this work that the precipitation and the denaturation processes of cellulase enzymes exist together.

Study of cellulase enzymes self-assembly in aqueous-acetonitrile solvent: Viscosity measurements

International Nuclear Information System (INIS)

Ghaouar, N.; Aschi, A.; Belbahri, L.; Trabelsi, S.; Gharbi, A.

2009-01-01

The present study extends the viscosity measurements performed by Ghaouar et al. [Physica B, submitted for publication.] to study the conformational change of the cellulase enzymes in aqueous-acetonitrile mixture. We aim to investigate: (i) the denaturation process by measuring the specific viscosity for temperatures varying between 25 and 65 deg. C and acetonitrile concentrations between 0% and 50%, (ii) the enzyme-enzyme interaction by calculating the Huggins coefficient and (iii) the enzyme sizes by following the hydrodynamic radius for various temperatures. The precipitation of cellulases versus acetonitrile concentration is also considered. We show from all physical quantities measured in this work that the precipitation and the denaturation processes of cellulase enzymes exist together.

Applying neural networks as software sensors for enzyme engineering.

Science.gov (United States)

Linko, S; Zhu, Y H; Linko, P

1999-04-01

The on-line control of enzyme-production processes is difficult, owing to the uncertainties typical of biological systems and to the lack of suitable on-line sensors for key process variables. For example, intelligent methods to predict the end point of fermentation could be of great economic value. Computer-assisted control based on artificial-neural-network models offers a novel solution in such situations. Well-trained feedforward-backpropagation neural networks can be used as software sensors in enzyme-process control; their performance can be affected by a number of factors.

Development of a commercial enzymes system for lignocellulosic biomass saccharification

Energy Technology Data Exchange (ETDEWEB)

Kumar, Manoj

2012-12-20

DSM Innovation Inc., in its four year effort was able to evaluate and develop its in-house DSM fungal cellulolytic enzymes system to reach enzyme efficiency mandates set by DoE Biomass program MYPP goals. DSM enzyme cocktail is uniquely active at high temperature and acidic pH, offering many benefits and product differentiation in 2G bioethanol production. Under this project, strain and process development, ratio optimization of enzymes, protein and genetic engineering has led to multitudes of improvement in productivity and efficiency making development of a commercial enzyme system for lignocellulosic biomass saccharification viable. DSM is continuing further improvement by additional biodiversity screening, protein engineering and overexpression of enzymes to continue to further lower the cost of enzymes for saccharification of biomass.

Polyphenol Oxidase Enzyme and Inactivation Methods

Directory of Open Access Journals (Sweden)

Leman Yılmaz

2018-03-01

Full Text Available Polyphenol oxidase enzyme is found in vegetables and fruits, as well as in some animal organs and microorganisms. Polyphenol oxidase enzyme responsible for enzymatic browning is a group of copper proteins that catalyses the oxidation of phenolic compounds to quinones, which produce brown pigments, commonly found in fruits and vegetables. During the industrial preparation of fruits and vegetables, results of catalytic effect of polyphenol oxidase causes enzymatic browning. Enzymatic browning impairs the appearance of products containing phenolic compounds along with undesirable colour, odor and taste formation and significant loss of nutritional value of the products. This affects the acceptability of the products by the consumers and causes economic losses. In this review, some characteristics of polyphenol oxidase enzyme in different fruits and vegetables have been reviewed and information about chemical antibrowning agents, thermal applications, irradiation applications and alternative methods such as high pressure processing, pulse electric field, supercritical carbon dioxide and ultrasound applications to inactivate this enzyme has been presented.

Screen-printable sol-gel enzyme-containing carbon inks.

Science.gov (United States)

Wang, J; Pamidi, P V; Park, D S

1996-08-01

Enzymes usually cannot withstand the high-temperature curing associated with the thick-film fabrication process and require a separate immobilization step in connection with the production of single-use biosensors. We report on the development of sol-gel-derived enzyme-containing carbon inks that display compatibility with the screen-printing process. Such coupling of sol-gel and thick-film technologies offers a one-step fabrication of disposable enzyme electrodes, as it obviates the need for thermal curing. The enzyme-containing sol-gel carbon ink, prepared by dispersing the biocatalyst, along with the graphite powder and a binder, within the sol-gel precursors, is cured very rapidly (10 min) at low temperature (4 °C). The influence of the ink preparation conditions is explored, and the sensor performance is evaluated in connection with the incorporation of glucose oxidase or horseradish peroxidase. The resulting strips are stable for at least 3 months. Such sol-gel-derived carbon inks should serve as hosts for other heat-sensitive biomaterials in connection with the microfabrication of various thick-film biosensors.

On the Temperature Dependence of Enzyme-Catalyzed Rates.

Science.gov (United States)

Arcus, Vickery L; Prentice, Erica J; Hobbs, Joanne K; Mulholland, Adrian J; Van der Kamp, Marc W; Pudney, Christopher R; Parker, Emily J; Schipper, Louis A

2016-03-29

One of the critical variables that determine the rate of any reaction is temperature. For biological systems, the effects of temperature are convoluted with myriad (and often opposing) contributions from enzyme catalysis, protein stability, and temperature-dependent regulation, for example. We have coined the phrase "macromolecular rate theory (MMRT)" to describe the temperature dependence of enzyme-catalyzed rates independent of stability or regulatory processes. Central to MMRT is the observation that enzyme-catalyzed reactions occur with significant values of ΔCp(‡) that are in general negative. That is, the heat capacity (Cp) for the enzyme-substrate complex is generally larger than the Cp for the enzyme-transition state complex. Consistent with a classical description of enzyme catalysis, a negative value for ΔCp(‡) is the result of the enzyme binding relatively weakly to the substrate and very tightly to the transition state. This observation of negative ΔCp(‡) has important implications for the temperature dependence of enzyme-catalyzed rates. Here, we lay out the fundamentals of MMRT. We present a number of hypotheses that arise directly from MMRT including a theoretical justification for the large size of enzymes and the basis for their optimum temperatures. We rationalize the behavior of psychrophilic enzymes and describe a "psychrophilic trap" which places limits on the evolution of enzymes in low temperature environments. One of the defining characteristics of biology is catalysis of chemical reactions by enzymes, and enzymes drive much of metabolism. Therefore, we also expect to see characteristics of MMRT at the level of cells, whole organisms, and even ecosystems.

Pancreatic Enzymes

Science.gov (United States)

... Contact Us DONATE NOW GENERAL DONATION PURPLESTRIDE Pancreatic enzymes Home Facing Pancreatic Cancer Living with Pancreatic Cancer ... and see a registered dietitian. What are pancreatic enzymes? Pancreatic enzymes help break down fats, proteins and ...

Application of enzymes in the textile industry: a review

OpenAIRE

Mojsov, Kiro

2011-01-01

The use of enzymes in textile industry is one of the most rapidly growing field in industrial enzymology. The enzymes used in the textile field are amylases, catalase, and laccase which are used to removing the starch, degrading excess hydrogen peroxide, bleaching textiles and degrading lignin. The use of enzymes in the textile chemical processing is rapidly gaining globally recognition because of their non-toxic and eco-friendly characteristics with the increasinly important requirements for...

Expression of lignocellulolytic enzymes in Pichia pastoris

Directory of Open Access Journals (Sweden)

Mellitzer Andrea

2012-05-01

Full Text Available Abstract Background Sustainable utilization of plant biomass as renewable source for fuels and chemical building blocks requires a complex mixture of diverse enzymes, including hydrolases which comprise the largest class of lignocellulolytic enzymes. These enzymes need to be available in large amounts at a low price to allow sustainable and economic biotechnological processes. Over the past years Pichia pastoris has become an attractive host for the cost-efficient production and engineering of heterologous (eukaryotic proteins due to several advantages. Results In this paper codon optimized genes and synthetic alcohol oxidase 1 promoter variants were used to generate Pichia pastoris strains which individually expressed cellobiohydrolase 1, cellobiohydrolase 2 and beta-mannanase from Trichoderma reesei and xylanase A from Thermomyces lanuginosus. For three of these enzymes we could develop strains capable of secreting gram quantities of enzyme per liter in fed-batch cultivations. Additionally, we compared our achieved yields of secreted enzymes and the corresponding activities to literature data. Conclusion In our experiments we could clearly show the importance of gene optimization and strain characterization for successfully improving secretion levels. We also present a basic guideline how to correctly interpret the interplay of promoter strength and gene dosage for a successful improvement of the secretory production of lignocellulolytic enzymes in Pichia pastoris.

Enzymes in CO2 Capture

DEFF Research Database (Denmark)

Fosbøl, Philip Loldrup; Gladis, Arne; Thomsen, Kaj

The enzyme Carbonic Anhydrase (CA) can accelerate the absorption rate of CO2 into aqueous solutions by several-fold. It exist in almost all living organisms and catalyses different important processes like CO2 transport, respiration and the acid-base balances. A new technology in the field...... of carbon capture is the application of enzymes for acceleration of typically slow ternary amines or inorganic carbonates. There is a hidden potential to revive currently infeasible amines which have an interesting low energy consumption for regeneration but too slow kinetics for viable CO2 capture. The aim...... of this work is to discuss the measurements of kinetic properties for CA promoted CO2 capture solvent systems. The development of a rate-based model for enzymes will be discussed showing the principles of implementation and the results on using a well-known ternary amine for CO2 capture. Conclusions...

Application of magnetic nanoparticles in smart enzyme immobilization.

Science.gov (United States)

Vaghari, Hamideh; Jafarizadeh-Malmiri, Hoda; Mohammadlou, Mojgan; Berenjian, Aydin; Anarjan, Navideh; Jafari, Nahideh; Nasiri, Shahin

2016-02-01

Immobilization of enzymes enhances their properties for efficient utilization in industrial processes. Magnetic nanoparticles, due to their high surface area, large surface-to-volume ratio and easy separation under external magnetic fields, are highly valued. Significant progress has been made to develop new catalytic systems that are immobilized onto magnetic nanocarriers. This review provides an overview of recent developments in enzyme immobilization and stabilization protocols using this technology. The current applications of immobilized enzymes based on magnetic nanoparticles are summarized and future growth prospects are discussed. Recommendations are also given for areas of future research.

Inhibition of β-Secretase Activity by Monoterpenes, Sesquiterpenes, and C13 Norisoprenoids.

Science.gov (United States)

Marumoto, Shinsuke; Okuno, Yoshiharu; Miyazawa, Mitsuo

2017-08-01

Inhibition of β-secretase (BACE1) is currently regarded as the leading treatment strategy for Alzheimer's disease. In the present study, we aimed to screen the in vitro inhibitory activity of 80 types of aroma compounds (monoterpenes, sesquiterpenes, and C 13 norisoprenoids), including plant-based types, at a 200-μM concentration against a recombinant human BACE1. The results showed that the most potent inhibitor of BACE1 was geranyl acetone followed by (+)-camphor, (-)-fenchone, (+)-fenchone, and (-)-camphor with the half-maximal inhibitory concentration (IC 50 ) values of 51.9 ± 3.9, 95.9 ± 11.0, 106.3 ± 14.9, 117.0 ± 18.6, and 134.1 ± 16.4 μM, respectively. Furthermore, the mechanism of inhibition of BACE1 by geranyl acetone was analyzed using Dixon kinetics plus Cornish-Bowden plots, which revealed mixed-type mode. Therefore aroma compounds may be used as potential lead molecules for designing anti-BACE1 agents.

Metrological aspects of enzyme production

International Nuclear Information System (INIS)

Kerber, T M; Pereira-Meirelles, F V; Dellamora-Ortiz, G M

2010-01-01

Enzymes are frequently used in biotechnology to carry out specific biological reactions, either in industrial processes or for the production of bioproducts and drugs. Microbial lipases are an important group of biotechnologically valuable enzymes that present widely diversified applications. Lipase production by microorganisms is described in several published papers; however, none of them refer to metrological evaluation and the estimation of the uncertainty in measurement. Moreover, few of them refer to process optimization through experimental design. The objectives of this work were to enhance lipase production in shaken-flasks with Yarrowia lipolytica cells employing experimental design and to evaluate the uncertainty in measurement of lipase activity. The highest lipolytic activity obtained was about three- and fivefold higher than the reported activities of CRMs BCR-693 and BCR-694, respectively. Lipase production by Y. lipolytica cells aiming the classification as certified reference material is recommended after further purification and stability studies

Novel enzymes for the degradation of cellulose

Directory of Open Access Journals (Sweden)

Horn Svein

2012-07-01

Full Text Available Abstract The bulk terrestrial biomass resource in a future bio-economy will be lignocellulosic biomass, which is recalcitrant and challenging to process. Enzymatic conversion of polysaccharides in the lignocellulosic biomass will be a key technology in future biorefineries and this technology is currently the subject of intensive research. We describe recent developments in enzyme technology for conversion of cellulose, the most abundant, homogeneous and recalcitrant polysaccharide in lignocellulosic biomass. In particular, we focus on a recently discovered new type of enzymes currently classified as CBM33 and GH61 that catalyze oxidative cleavage of polysaccharides. These enzymes promote the efficiency of classical hydrolytic enzymes (cellulases by acting on the surfaces of the insoluble substrate, where they introduce chain breaks in the polysaccharide chains, without the need of first “extracting” these chains from their crystalline matrix.

Effect of cadmium on lung lysosomal enzymes in vitro

International Nuclear Information System (INIS)

Giri, S.N.; Hollinger, M.A.

1995-01-01

Labilization of lysosomal enzymes is often associated with the general process of inflammation. The present study investigated the effect of the pneumotoxin cadmium on the release and activity of two lung lysosomal enzymes. Incubation of rat lung lysosomes with cadmium resulted in the release of β-glucuronidase but not acid phosphatase. The failure to ''release'' acid phosphatase appears to be the result of a direct inhibitory effect of cadmium on this enzyme. The K I for cadmium was determined to be 26.3 μM. The differential effect of cadmium on these two lysosomal enzymes suggests that caution should be exercised in selecting the appropriate enzyme marker for assessing lysosomal fragility in the presence of this toxicant. Furthermore, the differential basal release rate of the two enzymes from lung lysosomes may reflect the cellular heterogeneity of the lung. (orig.)

Molecular Imaging of Hydrolytic Enzymes Using PET and SPECT.

Science.gov (United States)

Rempel, Brian P; Price, Eric W; Phenix, Christopher P

2017-01-01

Hydrolytic enzymes are a large class of biological catalysts that play a vital role in a plethora of critical biochemical processes required to maintain human health. However, the expression and/or activity of these important enzymes can change in many different diseases and therefore represent exciting targets for the development of positron emission tomography (PET) and single-photon emission computed tomography (SPECT) radiotracers. This review focuses on recently reported radiolabeled substrates, reversible inhibitors, and irreversible inhibitors investigated as PET and SPECT tracers for imaging hydrolytic enzymes. By learning from the most successful examples of tracer development for hydrolytic enzymes, it appears that an early focus on careful enzyme kinetics and cell-based studies are key factors for identifying potentially useful new molecular imaging agents.

Measuring the Enzyme Activity of Arabidopsis Deubiquitylating Enzymes.

Science.gov (United States)

Kalinowska, Kamila; Nagel, Marie-Kristin; Isono, Erika

2016-01-01

Deubiquitylating enzymes, or DUBs, are important regulators of ubiquitin homeostasis and substrate stability, though the molecular mechanisms of most of the DUBs in plants are not yet understood. As different ubiquitin chain types are implicated in different biological pathways, it is important to analyze the enzyme characteristic for studying a DUB. Quantitative analysis of DUB activity is also important to determine enzyme kinetics and the influence of DUB binding proteins on the enzyme activity. Here, we show methods to analyze DUB activity using immunodetection, Coomassie Brilliant Blue staining, and fluorescence measurement that can be useful for understanding the basic characteristic of DUBs.

In-vitro engineering of novel bioactivity in the natural enzymes

Directory of Open Access Journals (Sweden)

Vishvanath Tiwari

2016-10-01

Full Text Available Enzymes catalyze various biochemical functions with high efficiency and specificity. In-vitro design of the enzyme leads to novel bioactivity in this natural biomolecule that give answers of some vital questions like crucial residues in binding with substrate, molecular evolution, cofactor specificity etc. Enzyme engineering technology involves directed evolution, rational designing, semi-rational designing and structure-based designing using chemical modifications. Similarly, combined computational and in-vitro evolution approaches together help in artificial designing of novel bioactivity in the natural enzyme. DNA shuffling, error prone PCR and staggered extension process are used to artificially redesign active site of enzyme, which can alter its efficiency and specificity. Modifications of the enzyme can lead to the discovery of new path of molecular evolution, designing of efficient enzymes, locating active sites and crucial residues, shift in substrate and cofactor specificity. The methods and thermodynamics of in-vitro designing of the enzyme are also discussed. Similarly, engineered thermophilic and psychrophilic enzymes attain substrate specificity and activity of mesophilic enzymes that may also be beneficial for industry and therapeutics.

Hide unhairing and characterization of commercial enzymes used in leather manufacture

Directory of Open Access Journals (Sweden)

A Dettmer

2011-09-01

Full Text Available The enzymatic treatment of hides in tannery processes is a promising technology. However, the reaction kinetics of commercial enzymes available to the leather industry are not fully understood and their activities have been mainly determined with model proteins such as casein as substrate, which are not of direct relevance for cattle hides. Therefore, it is important to determine their activities on collagen and keratin, the main proteins of skin, in order to use these enzymes in leather processing. This work describes the study of five proteases, used commercially in tanneries, to assess their ability to act upon collagen and keratin and to determine their unhairing. Results showed that all commercial enzymes tested had more activity on collagen than on keratin. Unhairing was also tested and four out of the five enzymes tested showed some unhairing activity. Optima of the temperature and pH of the enzymes were very similar for all five enzymes, with maximal activities around 55ºC and pH 9 to 12, respectively.

Lysosomal enzymes and their receptors in invertebrates: an evolutionary perspective.

Science.gov (United States)

Kumar, Nadimpalli Siva; Bhamidimarri, Poorna M

2015-01-01

Lysosomal biogenesis is an important process in eukaryotic cells to maintain cellular homeostasis. The key components that are involved in the biogenesis such as the lysosomal enzymes, their modifications and the mannose 6-phosphate receptors have been well studied and their evolutionary conservation across mammalian and non-mammalian vertebrates is clearly established. Invertebrate lysosomal biogenesis pathway on the other hand is not well studied. Although, details on mannose 6-phosphate receptors and enzymes involved in lysosomal enzyme modifications were reported earlier, a clear cut pathway has not been established. Recent research on the invertebrate species involving biogenesis of lysosomal enzymes suggests a possible conserved pathway in invertebrates. This review presents certain observations based on these processes that include biochemical, immunological and functional studies. Major conclusions include conservation of MPR-dependent pathway in higher invertebrates and recent evidence suggests that MPR-independent pathway might have been more prominent among lower invertebrates. The possible components of MPR-independent pathway that may play a role in lysosomal enzyme targeting are also discussed here.

Influence of high temperature and ethanol on thermostable lignocellulolytic enzymes

DEFF Research Database (Denmark)

Skovgaard, Pernille Anastasia; Jørgensen, Henning

2013-01-01

the influence of temperature and ethanol on enzyme activity and stability in the distillation step, where most enzymes are inactivated due to high temperatures. Two enzyme mixtures, a mesophilic and a thermostable mixture, were exposed to typical process conditions [temperatures from 55 to 65 °C and up to 5...... % ethanol (w/v)] followed by specific enzyme activity analyses and SDS-PAGE. The thermostable and mesophilic mixture remained active at up to 65 and 55 °C, respectively. When the enzyme mixtures reached their maximum temperature limit, ethanol had a remarkable influence on enzyme activity, e.g., the more...... ethanol, the faster the inactivation. The reason could be the hydrophobic interaction of ethanol on the tertiary structure of the enzyme protein. The thermostable mixture was more tolerant to temperature and ethanol and could therefore be a potential candidate for recycling after distillation....

Bioremediation of Industrial Waste Through Enzyme Producing Marine Microorganisms.

Science.gov (United States)

Sivaperumal, P; Kamala, K; Rajaram, R

Bioremediation process using microorganisms is a kind of nature-friendly and cost-effective clean green technology. Recently, biodegradation of industrial wastes using enzymes from marine microorganisms has been reported worldwide. The prospectus research activity in remediation area would contribute toward the development of advanced bioprocess technology. To minimize industrial wastes, marine enzymes could constitute a novel alternative in terms of waste treatment. Nowadays, the evidence on the mechanisms of bioremediation-related enzymes from marine microorganisms has been extensively studied. This review also will provide information about enzymes from various marine microorganisms and their complexity in the biodegradation of comprehensive range of industrial wastes. © 2017 Elsevier Inc. All rights reserved.

A roadmap to directed enzyme evolution and screening systems for biotechnological applications

Directory of Open Access Journals (Sweden)

Ronny Martínez

2013-01-01

Full Text Available Enzymes have been long used in man-made biochemical processes, from brewing and fermentation to current industrial production of fine chemicals. The ever-growing demand for enzymes in increasingly specific applications requires tailoring naturally occurring enzymes to the non-natural conditions found in industrial processes. Relationships between enzyme sequence, structure and activity are far from understood, thus hindering the capacity to design tailored biocatalysts. In the field of protein engineering, directed enzyme evolution is a powerful algorithm to generate and identify novel and improved enzymes through iterative rounds of mutagenesis and screening applying a specific evolutive pressure. In practice, critical checkpoints in directed evolution are: selection of the starting point, generation of the mutant library, development of the screening assay and analysis of the output of the screening campaign. Each step in directed evolution can be performed using conceptually and technically different approaches, all having inherent advantages and challenges. In this article, we present and discuss in a general overview, challenges of designing and performing a directed enzyme evolution campaign, current advances in methods, as well as highlighting some examples of its applications in industrially relevant enzymes.

Investigations of the efficiency of enzyme production technologies using modelling tools

DEFF Research Database (Denmark)

Albæk, Mads Orla; Gernaey, Krist; Hansen, Morten Skov

Growing markets and new innovative applications of industrial enzymes leads to increased interest in efficient production of these products. Most industrial enzymes are currently produced in traditional stirred tank reactors in submerged fed batch culture. The limiting parameter in such processes...... fermentations of the filamentous fungus Trichoderma reesei in 550litre pilot scale stirred tank reactors for a range of process conditions. Based on the experimental data a process model has been created, which satisfactory simulates the effect of the changing process conditions: Aeration rate, agitation speed...

Nanomaterials with enzyme-like characteristics (nanozymes): next-generation artificial enzymes.

Science.gov (United States)

Wei, Hui; Wang, Erkang

2013-07-21

Over the past few decades, researchers have established artificial enzymes as highly stable and low-cost alternatives to natural enzymes in a wide range of applications. A variety of materials including cyclodextrins, metal complexes, porphyrins, polymers, dendrimers and biomolecules have been extensively explored to mimic the structures and functions of naturally occurring enzymes. Recently, some nanomaterials have been found to exhibit unexpected enzyme-like activities, and great advances have been made in this area due to the tremendous progress in nano-research and the unique characteristics of nanomaterials. To highlight the progress in the field of nanomaterial-based artificial enzymes (nanozymes), this review discusses various nanomaterials that have been explored to mimic different kinds of enzymes. We cover their kinetics, mechanisms and applications in numerous fields, from biosensing and immunoassays, to stem cell growth and pollutant removal. We also summarize several approaches to tune the activities of nanozymes. Finally, we make comparisons between nanozymes and other catalytic materials (other artificial enzymes, natural enzymes, organic catalysts and nanomaterial-based catalysts) and address the current challenges and future directions (302 references).

From Protein Engineering to Immobilization: Promising Strategies for the Upgrade of Industrial Enzymes

Science.gov (United States)

Singh, Raushan Kumar; Tiwari, Manish Kumar; Singh, Ranjitha; Lee, Jung-Kul

2013-01-01

Enzymes found in nature have been exploited in industry due to their inherent catalytic properties in complex chemical processes under mild experimental and environmental conditions. The desired industrial goal is often difficult to achieve using the native form of the enzyme. Recent developments in protein engineering have revolutionized the development of commercially available enzymes into better industrial catalysts. Protein engineering aims at modifying the sequence of a protein, and hence its structure, to create enzymes with improved functional properties such as stability, specific activity, inhibition by reaction products, and selectivity towards non-natural substrates. Soluble enzymes are often immobilized onto solid insoluble supports to be reused in continuous processes and to facilitate the economical recovery of the enzyme after the reaction without any significant loss to its biochemical properties. Immobilization confers considerable stability towards temperature variations and organic solvents. Multipoint and multisubunit covalent attachments of enzymes on appropriately functionalized supports via linkers provide rigidity to the immobilized enzyme structure, ultimately resulting in improved enzyme stability. Protein engineering and immobilization techniques are sequential and compatible approaches for the improvement of enzyme properties. The present review highlights and summarizes various studies that have aimed to improve the biochemical properties of industrially significant enzymes. PMID:23306150

From protein engineering to immobilization: promising strategies for the upgrade of industrial enzymes.

Science.gov (United States)

Singh, Raushan Kumar; Tiwari, Manish Kumar; Singh, Ranjitha; Lee, Jung-Kul

2013-01-10

Enzymes found in nature have been exploited in industry due to their inherent catalytic properties in complex chemical processes under mild experimental and environmental conditions. The desired industrial goal is often difficult to achieve using the native form of the enzyme. Recent developments in protein engineering have revolutionized the development of commercially available enzymes into better industrial catalysts. Protein engineering aims at modifying the sequence of a protein, and hence its structure, to create enzymes with improved functional properties such as stability, specific activity, inhibition by reaction products, and selectivity towards non-natural substrates. Soluble enzymes are often immobilized onto solid insoluble supports to be reused in continuous processes and to facilitate the economical recovery of the enzyme after the reaction without any significant loss to its biochemical properties. Immobilization confers considerable stability towards temperature variations and organic solvents. Multipoint and multisubunit covalent attachments of enzymes on appropriately functionalized supports via linkers provide rigidity to the immobilized enzyme structure, ultimately resulting in improved enzyme stability. Protein engineering and immobilization techniques are sequential and compatible approaches for the improvement of enzyme properties. The present review highlights and summarizes various studies that have aimed to improve the biochemical properties of industrially significant enzymes.

Continuous recycling of enzymes during production of lignocellulosic bioethanol in demonstration scale

DEFF Research Database (Denmark)

Haven, Mai Østergaard; Lindedam, Jane; Jeppesen, Martin D.

2015-01-01

Recycling of enzymes in production of lignocellulosic bioethanol has been tried for more than 30 years. So far, the successes have been few and the experiments have been carried out at conditions far from those in an industrially feasible process. Here we have tested continuous enzyme recycling a...... broth also opens up the possibility of lowering the dry matter content in hydrolysis and fermentation while still maintaining high ethanol concentrations....... at demonstration scale using industrial process conditions (high dry matter content and low enzyme dosage) for a period of eight days. The experiment was performed at the Inbicon demonstration plant (Kalundborg, Denmark) capable of converting four tonnes of wheat straw per hour. 20% of the fermentation broth...... was recycled to the hydrolysis reactor while enzyme dosage was reduced by 5%. The results demonstrate that recycling enzymes by this method can reduce overall enzyme consumption and may also increase the ethanol concentrations in the fermentation broth. Our results further show that recycling fermentation...

The dynamic basis of energy transduction in enzymes.

Science.gov (United States)

Somogyi, B; Welch, G R; Damjanovich, S

1984-09-06

The most important idea underlying our treatment herein is the unity of the enzyme molecule and the medium. Appreciation of this relationship is vital, if enzymology is to graduate from its present reductionistic status to a more holistic posture. Enzymes are biological entities firstly, and isolated objects of physicochemical analysis secondly. Perhaps the most crucial 'biological lesson', particularly apropos of enzymes in intermediary metabolism, concerns the 'cytosociology' of enzyme action in vivo [94,128]. The natural habitat of many enzymes in the living cell is far different from that in bulk aqueous solution in vitro. In order to obtain a real grasp of the nature of enzyme function, one must ultimately couch enzymology in concepts emerging from contemporary cell biology [95]. Notwithstanding, analysis precedes synthesis; and one must needs begin with the individual enzyme molecule. The trenchant efforts of the physical chemist and the organic chemist have produced a wealth of information on the nature of the binding and catalytic events at the enzyme active site. While it is not yet possible to explain precisely the complete sequence of events in the catalytic process, nevertheless, the basic mechanisms by which enzymes effect catalysis (i.e., reduce activation energy) now seem apparent [81,129]. The new frontier is to be found, in exploring the dynamic role of the protein matrix [17]. Not only does the protein provide the 3-D scaffolding for active-site processes, but, more importantly, it serves as the local solvent for the bound chemical subsystem. Thus, the dynamical aspects of enzyme catalysis (for thermally based systems) must arise from the fluctuational properties of the protein molecule. This notion is the common denominator in all of the models in subsection IIC. It is the anisotropic nature of this fluctuational behavior, which would characterize the energy-transduction phenomenon leading to localized catalytic events at the active-site. In

EFFECT OF ENDOSPERM HARDNESS ON AN ETHANOL PROCESS USING A GRANULAR STARCH HYDROLYZING ENZYME

Energy Technology Data Exchange (ETDEWEB)

Wang, P; W Liu, D B; Johnston, K D; Rausch, S J; Schmidt, M E; Tumbleson, V Singh

2010-01-01

Granular starch hydrolyzing enzymes (GSHE) can hydrolyze starch at low temperature (32°C). The dry grind process using GSHE (GSH process) has fewer unit operations and no changes in process conditions (pH 4.0 and 32°C) compared to the conventional process because it dispenses with the cooking and liquefaction step. In this study, the effects of endosperm hardness, protease, urea, and GSHE levels on GSH process were evaluated. Ground corn, soft endosperm, and hard endosperm were processed using two GSHE levels (0.1 and 0.4 mL per 100 g ground material) and four treatments of protease and urea addition. Soft and hard endosperm materials were obtained by grinding and sifting flaking grits from a dry milling pilot plant; classifications were confirmed using scanning electron microscopy. During 72 h of simultaneous granular starch hydrolysis and fermentation (GSHF), ethanol and glucose profiles were determined using HPLC. Soft endosperm resulted in higher final ethanol concentrations compared to ground corn or hard endosperm. Addition of urea increased final ethanol concentrations for soft and hard endosperm. Protease addition increased ethanol concentrations and fermentation rates for soft endosperm, hard endosperm, and ground corn. The effect of protease addition on ethanol concentrations and fermentation rates was most predominant for soft endosperm, less for hard endosperm, and least for ground corn. Samples (soft endosperm, hard endosperm, or corn) with protease resulted in higher (1.0% to 10.5% v/v) ethanol concentration compared to samples with urea. The GSH process with protease requires little or no urea addition. For fermentation of soft endosperm, GSHE dose can be reduced. Due to nutrients (lipids, minerals, and soluble proteins) present in corn that enhance yeast growth, ground corn fermented faster at the beginning than hard and soft endosperm.

Production of fructose-containing syrup with enzymes

Energy Technology Data Exchange (ETDEWEB)

Helwiig-Nielsen, B

1981-01-01

A review on enzymic processes used for production of fructose- high syrup from starch including liquefaction by alpha-amylase, saccharification by amyloglucosidase, and isomerization with glucose isomerase.

[Advances on enzymes and enzyme inhibitors research based on microfluidic devices].

Science.gov (United States)

Hou, Feng-Hua; Ye, Jian-Qing; Chen, Zuan-Guang; Cheng, Zhi-Yi

2010-06-01

With the continuous development in microfluidic fabrication technology, microfluidic analysis has evolved from a concept to one of research frontiers in last twenty years. The research of enzymes and enzyme inhibitors based on microfluidic devices has also made great progress. Microfluidic technology improved greatly the analytical performance of the research of enzymes and enzyme inhibitors by reducing the consumption of reagents, decreasing the analysis time, and developing automation. This review focuses on the development and classification of enzymes and enzyme inhibitors research based on microfluidic devices.

Application of ionic liquids based enzyme-assisted extraction of chlorogenic acid from Eucommia ulmoides leaves

Energy Technology Data Exchange (ETDEWEB)

Liu, Tingting; Sui, Xiaoyu, E-mail: suixiaoyu@outlook.com; Li, Li; Zhang, Jie; Liang, Xin; Li, Wenjing; Zhang, Honglian; Fu, Shuang

2016-01-15

A new approach for ionic liquid based enzyme-assisted extraction (ILEAE) of chlorogenic acid (CGA) from Eucommia ulmoides is presented in which enzyme pretreatment was used in ionic liquids aqueous media to enhance extraction yield. For this purpose, the solubility of CGA and the activity of cellulase were investigated in eight 1-alkyl-3-methylimidazolium ionic liquids. Cellulase in 0.5 M [C6mim]Br aqueous solution was found to provide better performance in extraction. The factors of ILEAE procedures including extraction time, extraction phase pH, extraction temperatures and enzyme concentrations were investigated. Moreover, the novel developed approach offered advantages in term of yield and efficiency compared with other conventional extraction techniques. Scanning electronic microscopy of plant samples indicated that cellulase treated cell wall in ionic liquid solution was subjected to extract, which led to more efficient extraction by reducing mass transfer barrier. The proposed ILEAE method would develope a continuous process for enzyme-assisted extraction including enzyme incubation and solvent extraction process. In this research, we propose a novel view for enzyme-assisted extraction of plant active component, besides concentrating on enzyme facilitated cell wall degradation, focusing on improvement of bad permeability of ionic liquids solutions. - Highlights: • An ionic liquid based enzyme-assisted extraction method of natural product was explored. • ILEAE utilizes enzymatic treatment to improve permeability of ionic liquids solution. • Enzyme incubation and solvent extraction process were ongoing simultaneously. • ILEAE process simplified operating process and suitable for more complete extraction.

Application of ionic liquids based enzyme-assisted extraction of chlorogenic acid from Eucommia ulmoides leaves

International Nuclear Information System (INIS)

Liu, Tingting; Sui, Xiaoyu; Li, Li; Zhang, Jie; Liang, Xin; Li, Wenjing; Zhang, Honglian; Fu, Shuang

2016-01-01

A new approach for ionic liquid based enzyme-assisted extraction (ILEAE) of chlorogenic acid (CGA) from Eucommia ulmoides is presented in which enzyme pretreatment was used in ionic liquids aqueous media to enhance extraction yield. For this purpose, the solubility of CGA and the activity of cellulase were investigated in eight 1-alkyl-3-methylimidazolium ionic liquids. Cellulase in 0.5 M [C6mim]Br aqueous solution was found to provide better performance in extraction. The factors of ILEAE procedures including extraction time, extraction phase pH, extraction temperatures and enzyme concentrations were investigated. Moreover, the novel developed approach offered advantages in term of yield and efficiency compared with other conventional extraction techniques. Scanning electronic microscopy of plant samples indicated that cellulase treated cell wall in ionic liquid solution was subjected to extract, which led to more efficient extraction by reducing mass transfer barrier. The proposed ILEAE method would develope a continuous process for enzyme-assisted extraction including enzyme incubation and solvent extraction process. In this research, we propose a novel view for enzyme-assisted extraction of plant active component, besides concentrating on enzyme facilitated cell wall degradation, focusing on improvement of bad permeability of ionic liquids solutions. - Highlights: • An ionic liquid based enzyme-assisted extraction method of natural product was explored. • ILEAE utilizes enzymatic treatment to improve permeability of ionic liquids solution. • Enzyme incubation and solvent extraction process were ongoing simultaneously. • ILEAE process simplified operating process and suitable for more complete extraction.

Direct comparison of enzyme histochemical and immunohistochemical methods to localize an enzyme

NARCIS (Netherlands)

van Noorden, Cornelis J. F.

2002-01-01

Immunohistochemical localization of enzymes is compared directly with localization of enzyme activity with (catalytic) enzyme histochemical methods. The two approaches demonstrate principally different aspects of an enzyme. The immunohistochemical method localizes the enzyme protein whether it is

Process control of an ethanol fermentation with an enzyme thermistor as a sucrose sensor

Energy Technology Data Exchange (ETDEWEB)

Mandenius, C F; Danielsson, B; Mattiasson, B

1981-01-01

An enzyme thermistor was used to monitor and control the sucrose concentration in a conversion of sucrose to EtOH with immobilized yeast. A continuous stirred tank reactor containing Ca alginate-immobilized Saccharomyces cerevisiae was used. The enzyme thermistor continuously measured the sucrose concentration in the fermentor with an online arrangement giving stable and reproducible heat signals. The control of the sucrose concentration level was performed with an analog P1-controller.

Computational enzyme design: transitioning from catalytic proteins to enzymes.

Science.gov (United States)

Mak, Wai Shun; Siegel, Justin B

2014-08-01

The widespread interest in enzymes stem from their ability to catalyze chemical reactions under mild and ecologically friendly conditions with unparalleled catalytic proficiencies. While thousands of naturally occurring enzymes have been identified and characterized, there are still numerous important applications for which there are no biological catalysts capable of performing the desired chemical transformation. In order to engineer enzymes for which there is no natural starting point, efforts using a combination of quantum chemistry and force-field based protein molecular modeling have led to the design of novel proteins capable of catalyzing chemical reactions not catalyzed by naturally occurring enzymes. Here we discuss the current status and potential avenues to pursue as the field of computational enzyme design moves forward. Published by Elsevier Ltd.

ExplorEnz: the primary source of the IUBMB enzyme list

Science.gov (United States)

McDonald, Andrew G.; Boyce, Sinéad; Tipton, Keith F.

2009-01-01

ExplorEnz is the MySQL database that is used for the curation and dissemination of the International Union of Biochemistry and Molecular Biology (IUBMB) Enzyme Nomenclature. A simple web-based query interface is provided, along with an advanced search engine for more complex Boolean queries. The WWW front-end is accessible at http://www.enzyme-database.org, from where downloads of the database as SQL and XML are also available. An associated form-based curatorial application has been developed to facilitate the curation of enzyme data as well as the internal and public review processes that occur before an enzyme entry is made official. Suggestions for new enzyme entries, or modifications to existing ones, can be made using the forms provided at http://www.enzyme-database.org/forms.php. PMID:18776214

Considerations for implementation of novel enzyme-based processes

DEFF Research Database (Denmark)

Deslauriers, Maria Gundersen

Biocatalysis is the use of enzymes to catalyze chemical reactions. It is an established synthesisroute in chemical synthesis, alongside conventional chemistry. Biocatalysis is often applied due to excellent regio and stereoselectivity, in addition to its environmentally benign properties....... This thesis aims at increasing the potential use of industrial biocatalysis, both in terms of broadening its current use and expanding it to new applications. This academic study is carried out through two case studies. These two case studies were chosen because they represent each end of the spectra...... learned from these two case studies justify general conclusions for biocatalysis, irrespective of their application. The work in this thesis therefore contributes, not only to industrial biocatalysis in these two areas, but also increases the understanding of biocatalysis as a whole....

Evaluation of the energy efficiency of enzyme fermentation by mechanistic modeling.

Science.gov (United States)

Albaek, Mads O; Gernaey, Krist V; Hansen, Morten S; Stocks, Stuart M

2012-04-01

Modeling biotechnological processes is key to obtaining increased productivity and efficiency. Particularly crucial to successful modeling of such systems is the coupling of the physical transport phenomena and the biological activity in one model. We have applied a model for the expression of cellulosic enzymes by the filamentous fungus Trichoderma reesei and found excellent agreement with experimental data. The most influential factor was demonstrated to be viscosity and its influence on mass transfer. Not surprisingly, the biological model is also shown to have high influence on the model prediction. At different rates of agitation and aeration as well as headspace pressure, we can predict the energy efficiency of oxygen transfer, a key process parameter for economical production of industrial enzymes. An inverse relationship between the productivity and energy efficiency of the process was found. This modeling approach can be used by manufacturers to evaluate the enzyme fermentation process for a range of different process conditions with regard to energy efficiency. Copyright © 2011 Wiley Periodicals, Inc.

Evaluation of the efficiency of alternative enzyme production technologies

Energy Technology Data Exchange (ETDEWEB)

Albaek, M.O.

2012-03-15

Enzymes are used in an increasing number of industries. The application of enzymes is extending into the production of lignocellulosic ethanol in processes that economically can compete with fossil fuels. Since lignocellulosic ethanol is based on renewable resources it will have a positive impact on for example the emission of green house gasses. Cellulases and hemi-cellulases are used for enzymatic hydrolysis of pretreated lignocellulosic biomass, and fermentable sugars are released upon the enzymatic process. Even though many years of research has decreased the amount of enzyme needed in the process, the cost of enzymes is still considered a bottleneck in the economic feasibility of lignocellulose utilization. The purpose of this project was to investigate and compare different technologies for production of these enzymes. The filamentous fungus Trichoderma reesei is currently used for industrial production of cellulases and hemi-cellulases. The aim of the thesis was to use modeling tools to identify alternative technologies that have higher energy or raw material efficiency than the current technology. The enzyme production by T. reesei was conducted as an aerobic fed-batch fermentation. The process was carried out in pilot scale stirred tank reactors and based on a range of different process conditions, a process model was constructed which satisfactory described the course of fermentation. The process was governed by the rate limiting mass transfer of oxygen from the gas to the liquid phase. During fermentation, filamentous growth of the fungus lead to increased viscosity which hindered mass transfer. These mechanisms were described by a viscosity model based on the biomass concentration of the fermentation broth and a mass transfer correlation that incorporated a viscosity term. An analysis of the uncertainty and sensitivity of the model indicated the biological parameters to be responsible for most of the model uncertainty. A number of alternative

Design of novel nano-carriers for multi-enzyme co-localization

Energy Technology Data Exchange (ETDEWEB)

Jia, Feng [Iowa State Univ., Ames, IA (United States)

2013-01-01

The main objective of this project is to design novel nano-structured carriers and strategies to co-localize multiple enzymes to mimic the functionalities of MECs. In order to achieve this goal, distinct approaches for enzyme co-localization were developed and evaluated. Specifically, we investigated different polymeric nano-carriers, both flexible and rigid, as platforms for co-localization, as well as distinct enzyme attachment techniques using model enzyme systems using glucose oxidase and horseradish peroxidase to control the spatial arrangement of the multiple enzymes on the nanocarriers. This platform technology can be potentially used to co-localize various enzyme systems and its broad applicability will be tested using the sclareol biosynthesis process to control the formation of products through the formation of MECs with multiple enzymes NgCPS and sSsSS to regulate the pathway of reactive intermediate to enhance the final product conversion rate.

Study on the inactivation of intracellular enzyme molecules by X-ray irradiation

International Nuclear Information System (INIS)

Lee, S.B.

1977-01-01

Inactivation of the glutamic acid dehydrogenase and glucose-6-phosphate dehydrogenase enzyme molecules in the Ehrlich ascites tumor cells of the mouse were studied. The above mentioned intracellular enzyme molecules were irradiated by the X-ray radiation under the condition of 65 kV, 1 Amp under the atmosphere of nitrogen gases and by 4 0 C. Thereby, irradiation doses were 580 KR/min(error: +-3%). After irradiation, the cell homogentes were prepared through liquid air techniques. There after, the activities of the enzymes were measured with photometric method given by O. Warburg and W. Christian. The dose effect curves of the activities of the two enzymes by the X-ray irradiation showed both exponential and the inactivation doses were 6.5x10 6 and 5.0x10 6 R respectively. These results showed one side that the inactivation process of the intracellular enzyme molecules was one hit reaction after target theory, and the other side that this inactivation process could not be the primary causes of the death through X-ray irradiation of the vertebrate animals, because of the high resistance of the intracellular protein molecules against X-ray irradiation. The one hit reaction by the inactivation process of the irradiated intracellular enzyme molecules was discussed. (author)

Network analysis of metabolic enzyme evolution in Escherichia coli

Directory of Open Access Journals (Sweden)

Kraulis Per

2004-02-01

Full Text Available Abstract Background The two most common models for the evolution of metabolism are the patchwork evolution model, where enzymes are thought to diverge from broad to narrow substrate specificity, and the retrograde evolution model, according to which enzymes evolve in response to substrate depletion. Analysis of the distribution of homologous enzyme pairs in the metabolic network can shed light on the respective importance of the two models. We here investigate the evolution of the metabolism in E. coli viewed as a single network using EcoCyc. Results Sequence comparison between all enzyme pairs was performed and the minimal path length (MPL between all enzyme pairs was determined. We find a strong over-representation of homologous enzymes at MPL 1. We show that the functionally similar and functionally undetermined enzyme pairs are responsible for most of the over-representation of homologous enzyme pairs at MPL 1. Conclusions The retrograde evolution model predicts that homologous enzymes pairs are at short metabolic distances from each other. In general agreement with previous studies we find that homologous enzymes occur close to each other in the network more often than expected by chance, which lends some support to the retrograde evolution model. However, we show that the homologous enzyme pairs which may have evolved through retrograde evolution, namely the pairs that are functionally dissimilar, show a weaker over-representation at MPL 1 than the functionally similar enzyme pairs. Our study indicates that, while the retrograde evolution model may have played a small part, the patchwork evolution model is the predominant process of metabolic enzyme evolution.

A role for 12/15 lipoxygenase in the amyloid beta precursor protein metabolism.

Science.gov (United States)

Succol, Francesca; Praticò, Domenico

2007-10-01

12/15 Lipoxygenase (12/15LO) protein levels and activity are increased in pathologically affected regions of Alzheimer's disease (AD) brains, compared with controls. Its metabolic products are elevated in cerebrospinal fluid of patients with AD and individuals with mild cognitive impairment, suggesting that this enzyme may be involved early in AD pathogenesis. Herein, we investigate the effect of pharmacologic inhibition of 12/15LO on the amyloid beta precursor protein (APP) metabolism. To this end, we used CHO and N2A cells stably expressing human APP with the Swedish mutant, and two structurally distinct and selective 12/15LO inhibitors, PD146176 and CDC. Our results demonstrated that both drugs dose-dependently reduced Abeta formation without affecting total APP levels. Interestingly, in the same cells we observed a significant reduction in secreted (s)APPbeta and beta-secretase (BACE), but not sAPPalpha and ADAM10 protein levels. Together, these data show for the first time that this enzymatic pathway influences Abeta formation whereby modulating the BACE proteolytic cascade. We conclude that specific pharmacologic inhibition of 12/15LO could represent a novel therapeutic target for treating or preventing AD pathology in humans.

A novel blood-brain barrier co-culture system for drug targeting of Alzheimer's disease: establishment by using acitretin as a model drug.

Science.gov (United States)

Freese, Christian; Reinhardt, Sven; Hefner, Gudrun; Unger, Ronald E; Kirkpatrick, C James; Endres, Kristina

2014-01-01

In the pathogenesis of Alzheimer's disease (AD) the homeostasis of amyloid precursor protein (APP) processing in the brain is impaired. The expression of the competing proteases ADAM10 (a disintegrin and metalloproteinase 10) and BACE-1 (beta site APP cleaving enzyme 1) is shifted in favor of the A-beta generating enzyme BACE-1. Acitretin--a synthetic retinoid-e.g., has been shown to increase ADAM10 gene expression, resulting in a decreased level of A-beta peptides within the brain of AD model mice and thus is of possible value for AD therapy. A striking challenge in evaluating novel therapeutically applicable drugs is the analysis of their potential to overcome the blood-brain barrier (BBB) for central nervous system targeting. In this study, we established a novel cell-based bio-assay model to test ADAM10-inducing drugs for their ability to cross the BBB. We therefore used primary porcine brain endothelial cells (PBECs) and human neuroblastoma cells (SH-SY5Y) transfected with an ADAM10-promoter luciferase reporter vector in an indirect co-culture system. Acitretin served as a model substance that crosses the BBB and induces ADAM10 expression. We ensured that ADAM10-dependent constitutive APP metabolism in the neuronal cells was unaffected under co-cultivation conditions. Barrier properties established by PBECs were augmented by co-cultivation with SH-SY5Y cells and they remained stable during the treatment with acitretin as demonstrated by electrical resistance measurement and permeability-coefficient determination. As a consequence of transcellular acitretin transport measured by HPLC, the activity of the ADAM10-promoter reporter gene was significantly increased in co-cultured neuronal cells as compared to vehicle-treated controls. In the present study, we provide a new bio-assay system relevant for the study of drug targeting of AD. This bio-assay can easily be adapted to analyze other Alzheimer- or CNS disease-relevant targets in neuronal cells, as their

Stabilization of enzymes in ionic liquids via modification of enzyme charge.

Science.gov (United States)

Nordwald, Erik M; Kaar, Joel L

2013-09-01

Due to the propensity of ionic liquids (ILs) to inactivate enzymes, the development of strategies to improve enzyme utility in these solvents is critical to fully exploit ILs for biocatalysis. We have developed a strategy to broadly improve enzyme utility in ILs based on elucidating the effect of charge modifications on the function of enzymes in IL environments. Results of stability studies in aqueous-IL mixtures indicated a clear connection between the ratio of enzyme-containing positive-to-negative sites and enzyme stability in ILs. Stability studies of the effect of [BMIM][Cl] and [EMIM][EtSO4 ] on chymotrypsin specifically found an optimum ratio of positively-charged amine-to-negatively-charged acid groups (0.39). At this ratio, the half-life of chymotrypsin was increased 1.6- and 4.3-fold relative to wild-type chymotrypsin in [BMIM][Cl] and [EMIM][EtSO4 ], respectively. The half-lives of lipase and papain were similarly increased as much as 4.0 and 2.4-fold, respectively, in [BMIM][Cl] by modifying the ratio of positive-to-negative sites of each enzyme. More generally, the results of stability studies found that modifications that reduce the ratio of enzyme-containing positive-to-negative sites improve enzyme stability in ILs. Understanding the impact of charge modification on enzyme stability in ILs may ultimately be exploited to rationally engineer enzymes for improved function in IL environments. Copyright © 2013 Wiley Periodicals, Inc.

Enhancing polyphenol extraction from unripe apples by carbohydrate-hydrolyzing enzymes*

Science.gov (United States)

Zheng, Hu-zhe; Hwang, In-Wook; Chung, Shin-Kyo

2009-01-01

The effects of process variables such as enzyme types, enzyme ratio, reaction temperature, pH, time, and ethanol concentration on the extraction of unripe apple polyphenol were investigated. The results indicated that Viscozyme L had the strongest effect on polyphenols extraction and was selected to study the polyphenol composition. The ratio of enzyme (Viscozyme L) to substrate (2 fungal beta-glucanase units (FBG)) at 0.02, reaction at pH 3.7, 50 °C for 12 h, and ethanol concentration of 70% were chosen as the most favorable extraction condition. Total phenolic content (TPC), reducing sugar content (RSC), and extraction yield increased by about 3, 1.5, and 2 times, respectively, compared with control. The contents of p-coumaric acid, ferulic acid, and caffeic acid increased to 8, 4, and 32 times, respectively. The enzyme-aided polyphenol extraction process from unripe apples might be applied to food industry for enhancing bioactive compound production. PMID:19946955

Enhancing polyphenol extraction from unripe apples by carbohydrate-hydrolyzing enzymes.

Science.gov (United States)

Zheng, Hu-zhe; Hwang, In-Wook; Chung, Shin-Kyo

2009-12-01

The effects of process variables such as enzyme types, enzyme ratio, reaction temperature, pH, time, and ethanol concentration on the extraction of unripe apple polyphenol were investigated. The results indicated that Viscozyme L had the strongest effect on polyphenols extraction and was selected to study the polyphenol composition. The ratio of enzyme (Viscozyme L) to substrate (2 fungal beta-glucanase units (FBG)) at 0.02, reaction at pH 3.7, 50 degrees C for 12 h, and ethanol concentration of 70% were chosen as the most favorable extraction condition. Total phenolic content (TPC), reducing sugar content (RSC), and extraction yield increased by about 3, 1.5, and 2 times, respectively, compared with control. The contents of p-coumaric acid, ferulic acid, and caffeic acid increased to 8, 4, and 32 times, respectively. The enzyme-aided polyphenol extraction process from unripe apples might be applied to food industry for enhancing bioactive compound production.

EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 309 (FGE.309): Sodium Diacetate

DEFF Research Database (Denmark)

Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate sodium diacetate [FL-no: 16.073] in the Flavouring Group Evaluation 309, using the Procedure in Commission Regulation (EC) No 1565/2000. However, although...

Continuous recycling of enzymes during production of lignocellulosic bioethanol in demonstration scale

International Nuclear Information System (INIS)

Haven, Mai Østergaard; Lindedam, Jane; Jeppesen, Martin Dan; Elleskov, Michael; Rodrigues, Ana Cristina; Gama, Miguel; Jørgensen, Henning; Felby, Claus

2015-01-01

Highlights: • Results from continuous experiments in demonstration scale for a total of 16 days. • Reuse of enzymes is possible through recycling fermentation broth. • Recycling fermentation broth can increase ethanol concentration with lower dry matter. - Abstract: Recycling of enzymes in production of lignocellulosic bioethanol has been tried for more than 30 years. So far, the successes have been few and the experiments have been carried out at conditions far from those in an industrially feasible process. Here we have tested continuous enzyme recycling at demonstration scale using industrial process conditions (high dry matter content and low enzyme dosage) for a period of eight days. The experiment was performed at the Inbicon demonstration plant (Kalundborg, Denmark) capable of converting four tonnes of wheat straw per hour. 20% of the fermentation broth was recycled to the hydrolysis reactor while enzyme dosage was reduced by 5%. The results demonstrate that recycling enzymes by this method can reduce overall enzyme consumption and may also increase the ethanol concentrations in the fermentation broth. Our results further show that recycling fermentation broth also opens up the possibility of lowering the dry matter content in hydrolysis and fermentation while still maintaining high ethanol concentrations.

Investigation of some characteristics of enzymes that ensure the process of membrane digestion in paddlefish and Russian sturgeon

Directory of Open Access Journals (Sweden)

A. N. Nevalennyy

2010-01-01

Full Text Available Complex research of characteristics of some enzymes which are carrying out membrane hydrolysis of food at a spoonbilled cat and Russian sturgeon is carried out. High thermostability enzymes the squirrel of all investigated enzymes is marked.

Artificial Enzymes, "Chemzymes"

DEFF Research Database (Denmark)

Bjerre, Jeannette; Rousseau, Cyril Andre Raphaël; Pedersen, Lavinia Georgeta M

2008-01-01

Enzymes have fascinated scientists since their discovery and, over some decades, one aim in organic chemistry has been the creation of molecules that mimic the active sites of enzymes and promote catalysis. Nevertheless, even today, there are relatively few examples of enzyme models that successf......Enzymes have fascinated scientists since their discovery and, over some decades, one aim in organic chemistry has been the creation of molecules that mimic the active sites of enzymes and promote catalysis. Nevertheless, even today, there are relatively few examples of enzyme models...... that successfully perform Michaelis-Menten catalysis under enzymatic conditions (i.e., aqueous medium, neutral pH, ambient temperature) and for those that do, very high rate accelerations are seldomly seen. This review will provide a brief summary of the recent developments in artificial enzymes, so called...... "Chemzymes", based on cyclodextrins and other molecules. Only the chemzymes that have shown enzyme-like activity that has been quantified by different methods will be mentioned. This review will summarize the work done in the field of artificial glycosidases, oxidases, epoxidases, and esterases, as well...

β-secretase inhibitor; a promising novel therapeutic drug in AD

Directory of Open Access Journals (Sweden)

Kelly Willemijn Menting

2014-07-01

Full Text Available Alzheimer’s disease (AD and vascular dementia are responsible for up to 90% of dementia cases. According to the World Health Organization (WHO, a staggering number of 35.6 million people are currently diagnosed with dementia. Blocking disease progression or preventing AD altogether is desirable for both social and economic reasons and recently focus has shifted to a new and promising drug: the β-secretase inhibitor. Much of AD research has investigated the amyloid cascade hypothesis, which postulates that AD is caused by changes in amyloid beta (Aβ stability and aggregation. Blocking Aβ production by inhibiting the first protease required for its generation, β-secretase/BACE1, may be the next step in blocking AD progression. In April 2012, promising phase I data on inhibitor MK-8931 was presented. This drug reduced Aβ CSF levels up to 92% and was well tolerated by patients. In March 2013 data was added from a one week trial in 32 mild to moderate AD patients, showing CSF Aβ levels decreased up to 84%. However, BACE1 inhibitors require further research. First, greatly reducing Aβ levels through BACE1 inhibition may have harmful side effects. Second, BACE1 inhibitors have yet to pass clinical trial phase II/III and no data on possible side effects on AD patients are available. And third, there remains doubt about the clinical efficacy of BACE1 inhibitors. In moderate AD patients, Aβ plaques have already been formed. BACE1 inhibitors prevent production of new Aβ plaques, but hypothetically do not influence already existing Aβ peptides. Therefore, BACE1 inhibitors are potentially better at preventing AD instead of having therapeutic use.

Development of a classification scheme for disease-related enzyme information

Directory of Open Access Journals (Sweden)

Söhngen Carola

2011-08-01

Full Text Available Abstract Background BRENDA (BRaunschweig ENzyme DAtabase, http://www.brenda-enzymes.org is a major resource for enzyme related information. First and foremost, it provides data which are manually curated from the primary literature. DRENDA (Disease RElated ENzyme information DAtabase complements BRENDA with a focus on the automatic search and categorization of enzyme and disease related information from title and abstracts of primary publications. In a two-step procedure DRENDA makes use of text mining and machine learning methods. Results Currently enzyme and disease related references are biannually updated as part of the standard BRENDA update. 910,897 relations of EC-numbers and diseases were extracted from titles or abstracts and are included in the second release in 2010. The enzyme and disease entity recognition has been successfully enhanced by a further relation classification via machine learning. The classification step has been evaluated by a 5-fold cross validation and achieves an F1 score between 0.802 ± 0.032 and 0.738 ± 0.033 depending on the categories and pre-processing procedures. In the eventual DRENDA content every category reaches a classification specificity of at least 96.7% and a precision that ranges from 86-98% in the highest confidence level, and 64-83% for the smallest confidence level associated with higher recall. Conclusions The DRENDA processing chain analyses PubMed, locates references with disease-related information on enzymes and categorises their focus according to the categories causal interaction, therapeutic application, diagnostic usage and ongoing research. The categorisation gives an impression on the focus of the located references. Thus, the relation categorisation can facilitate orientation within the rapidly growing number of references with impact on diseases and enzymes. The DRENDA information is available as additional information in BRENDA.

Subunit topology in the V type ATPase and related enzymes

NARCIS (Netherlands)

Chaban, Yuriy

2005-01-01

During the last decades impressive progress has been made in understanding of the catalytic mechanism of F-type ATP synthase, which is the key enzyme in the energy metabolism of eukaryotes and most bacteria. This enzyme catalyzes the final step in the process of oxidative phosphorylation in bacteria

Enzymes from solvent-tolerant microbes: useful biocatalysts for non-aqueous enzymology.

Science.gov (United States)

Gupta, Anshu; Khare, S K

2009-01-01

Solvent-tolerant microbes are a newly emerging class that possesses the unique ability to thrive in the presence of organic solvents. Their enzymes adapted to mediate cellular and metabolic processes in a solvent-rich environment and are logically stable in the presence of organic solvents. Enzyme catalysis in non-aqueous/low-water media is finding increasing applications for the synthesis of industrially important products, namely peptides, esters, and other trans-esterification products. Solvent stability, however, remains a prerequisite for employing enzymes in non-aqueous systems. Enzymes, in general, get inactivated or give very low rates of reaction in non-aqueous media. Thus, early efforts, and even some recent ones, have aimed at stabilization of enzymes in organic media by immobilization, surface modifications, mutagenesis, and protein engineering. Enzymes from solvent-tolerant microbes appear to be the choicest source for studying solvent-stable enzymes because of their unique ability to survive in the presence of a range of organic solvents. These bacteria circumvent the solvent's toxic effects by virtue of various adaptations, e.g. at the level of the cytoplasmic membrane, by degradation and transformation of solvents, and by active excretion of solvents. The recent screening of these exotic microbes has generated some naturally solvent-stable proteases, lipases, cholesterol oxidase, cholesterol esterase, cyclodextrin glucanotransferase, and other important enzymes. The unique properties of these novel biocatalysts have great potential for applications in non-aqueous enzymology for a range of industrial processes.

Triazolyl tryptoline derivatives as β-secretase inhibitors

OpenAIRE

Jiaranaikulwanitch, Jutamas; Boonyarat, Chantana; Fokin, Valery V.; Vajragupta, Opa

2010-01-01

Tryptoline, a core structure of ochrolifuanine E, which is a hit compound from virtual screening of the Thai herbal database against BACE1 was used as a scaffold for the design of BACE1 inhibitors. The tryptoline was linked with different side chains by 1,2,3-triazole ring readily synthesized by catalytic azide-alkyne cycloaddition reactions. Twenty two triazolyl tryptoline derivatives were synthesized and screened for the inhibitory action against BACE1. JJCA-140 was the most potent inhibito...

Purification and properties of amylolytic enzyme from Aspergillus oryzae MIBA316

OpenAIRE

仮屋, 麻紀子; 矢野, めぐむ; 瀧井, 幸男; Makiko, Kariya; Megumu, Yano; Yukio, Takii

2003-01-01

Amylolytic enzyme was purified to electrophoretically homogeneous state from culture broth of Aspergillus oryzae MIBA316. This enzyme hydrolyzed preferentially amylopectin, starch and glycogen. Approaches to complete breakdown of starch to its components and their utilization in food processing were discussed.

Vacuolar processing enzyme plays an essential role in the crystalline structure of glutelin in rice seed.

Science.gov (United States)

Kumamaru, Toshihiro; Uemura, Yuji; Inoue, Yoshimi; Takemoto, Yoko; Siddiqui, Sadar Uddin; Ogawa, Masahiro; Hara-Nishimura, Ikuko; Satoh, Hikaru

2010-01-01

To identify the function of genes that regulate the processing of proglutelin, we performed an analysis of glup3 mutants, which accumulates excess amounts of proglutelin and lack the vacuolar processing enzyme (VPE). VPE activity in developing seeds from glup3 lines was reduced remarkably compared with the wild type. DNA sequencing of the VPE gene in glup3 mutants revealed either amino acid substitutions or the appearance of a stop codon within the coding region. Microscopic observations showed that alpha-globulin and proglutelin were distributed homogeneously within glup3 protein storage vacuoles (PSVs), and that glup3 PSVs lacked the crystalline lattice structure typical of wild-type PSVs. This suggests that the processing of proglutelin by VPE in rice is essential for proper PSV structure and compartmentalization of storage proteins. Growth retardation in glup3 seedlings was also observed, indicating that the processing of proglutelin influences early seedling development. These findings indicate that storage of glutelin in its mature form as a crystalline structure in PSVs is required for the rapid use of glutelin as a source of amino acids during early seedling development. In conclusion, VPE plays an important role in the formation of protein crystalline structures in PSVs.

Structural Basis of Multifunctionality in a Vitamin B[subscript 12]-processing Enzyme

Energy Technology Data Exchange (ETDEWEB)

Koutmos, Markos; Gherasim, Carmen; Smith, Janet L.; Banerjee, Ruma (Michigan)

2012-07-11

An early step in the intracellular processing of vitamin B{sub 12} involves CblC, which exhibits dual reactivity, catalyzing the reductive decyanation of cyanocobalamin (vitamin B{sub 12}), and the dealkylation of alkylcobalamins (e.g. methylcobalamin; MeCbl). Insights into how the CblC scaffold supports this chemical dichotomy have been unavailable despite it being the most common locus of patient mutations associated with inherited cobalamin disorders that manifest in both severe homocystinuria and methylmalonic aciduria. Herein, we report structures of human CblC, with and without bound MeCbl, which provide novel biochemical insights into its mechanism of action. Our results reveal that CblC is the most divergent member of the NADPH-dependent flavin reductase family and can use FMN or FAD as a prosthetic group to catalyze reductive decyanation. Furthermore, CblC is the first example of an enzyme with glutathione transferase activity that has a sequence and structure unrelated to the GST superfamily. CblC thus represents an example of evolutionary adaptation of a common structural platform to perform diverse chemistries. The CblC structure allows us to rationalize the biochemical basis of a number of pathological mutations associated with severe clinical phenotypes.

Recent advances in enzyme extraction strategies: A comprehensive review.

Science.gov (United States)

Nadar, Shamraja S; Pawar, Rohini G; Rathod, Virendra K

2017-08-01

The increasing interest of industrial enzymes demands for development of new downstream strategies for maximizing enzyme recovery. The significant efforts have been focused on the development of newly adapted technologies to purify enzymes in catalytically active form. Recently, an aqueous two phase system (ATPS) is emerged as powerful tools for efficient extraction and purification of enzymes due to their versatility, lower cost, process integration capability and easy scale-up. The present review gives an overview of effect of parameters such as tie line length, pH, neutral salts, properties of polymer and salt involved in traditional polymer/polymer and polymer/salt ATPS for enzyme recovery. Further, advanced ATPS have been developed based on alcohols, surfactants, micellar compounds to avoid tedious recovery steps for getting desired enzyme. In order to improve the selectivity and efficiency of ATPS, recent approaches of conventional ATPS combined with different techniques like affinity ligands, ionic liquids, thermoseparating polymers and microfluidic device based ATPS have been reviewed. Moreover, three phase partitioning is also highlighted for enzymes enrichment as a blooming technology for efficiently integrated bioseparation techniques. At the end, it includes an overview of CLEAs technology and organic-inorganic nanoflowers preparation as novel strategies for simultaneous extraction, purification and immobilization of enzymes. Copyright © 2017 Elsevier B.V. All rights reserved.

Multiple RNA processing defects and impaired chloroplast function in plants deficient in the organellar protein-only RNase P enzyme.

Directory of Open Access Journals (Sweden)

Wenbin Zhou

Full Text Available Transfer RNA (tRNA precursors undergo endoribonucleolytic processing of their 5' and 3' ends. 5' cleavage of the precursor transcript is performed by ribonuclease P (RNase P. While in most organisms RNase P is a ribonucleoprotein that harbors a catalytically active RNA component, human mitochondria and the chloroplasts (plastids and mitochondria of seed plants possess protein-only RNase P enzymes (PRORPs. The plant organellar PRORP (PRORP1 has been characterized to some extent in vitro and by transient gene silencing, but the molecular, phenotypic and physiological consequences of its down-regulation in stable transgenic plants have not been assessed. Here we have addressed the function of the dually targeted organellar PRORP enzyme in vivo by generating stably transformed Arabidopsis plants in which expression of the PRORP1 gene was suppressed by RNA interference (RNAi. PRORP1 knock-down lines show defects in photosynthesis, while mitochondrial respiration is not appreciably affected. In both plastids and mitochondria, the effects of PRORP1 knock-down on the processing of individual tRNA species are highly variable. The drastic reduction in the levels of mature plastid tRNA-Phe(GAA and tRNA-Arg(ACG suggests that these two tRNA species limit plastid gene expression in the PRORP1 mutants and, hence, are causally responsible for the mutant phenotype.

Enzyme detection by microfluidics

DEFF Research Database (Denmark)

2013-01-01

Microfluidic-implemented methods of detecting an enzyme, in particular a DNA-modifying enzyme, are provided, as well as methods for detecting a cell, or a microorganism expressing said enzyme. The enzyme is detected by providing a nucleic acid substrate, which is specifically targeted...... by that enzyme...

Conversion of xylan by recyclable spores of Bacillus subtilis displaying thermophilic enzymes.

Science.gov (United States)

Mattossovich, Rosanna; Iacono, Roberta; Cangiano, Giuseppina; Cobucci-Ponzano, Beatrice; Isticato, Rachele; Moracci, Marco; Ricca, Ezio

2017-11-28

The Bacillus subtilis spore has long been used to display antigens and enzymes. Spore display can be accomplished by a recombinant and a non-recombinant approach, with the latter proved more efficient than the recombinant one. We used the non-recombinant approach to independently adsorb two thermophilic enzymes, GH10-XA, an endo-1,4-β-xylanase (EC 3.2.1.8) from Alicyclobacillus acidocaldarius, and GH3-XT, a β-xylosidase (EC 3.2.1.37) from Thermotoga thermarum. These enzymes catalyze, respectively, the endohydrolysis of (1-4)-β-D-xylosidic linkages of xylans and the hydrolysis of (1-4)-β-D-xylans to remove successive D-xylose residues from the non-reducing termini. We report that both purified enzymes were independently adsorbed on purified spores of B. subtilis. The adsorption was tight and both enzymes retained part of their specific activity. When spores displaying either GH10-XA or GH3-XT were mixed together, xylan was hydrolysed more efficiently than by a mixture of the two free, not spore-adsorbed, enzymes. The high total activity of the spore-bound enzymes is most likely due to a stabilization of the enzymes that, upon adsorption on the spore, remained active at the reaction conditions for longer than the free enzymes. Spore-adsorbed enzymes, collected after the two-step reaction and incubated with fresh substrate, were still active and able to continue xylan degradation. The recycling of the mixed spore-bound enzymes allowed a strong increase of xylan degradation. Our results indicate that the two-step degradation of xylans can be accomplished by mixing spores displaying either one of two required enzymes. The two-step process occurs more efficiently than with the two un-adsorbed, free enzymes and adsorbed spores can be reused for at least one other reaction round. The efficiency of the process, the reusability of the adsorbed enzymes, and the well documented robustness of spores of B. subtilis indicate the spore as a suitable platform to display enzymes

Comparative study of pulsed electric field and thermal processing of apple juice with particular consideration of juice quality and enzyme deactivation.

Science.gov (United States)

Schilling, Susanne; Schmid, Sandra; Jäger, Henry; Ludwig, Michael; Dietrich, Helmut; Toepfl, Stefan; Knorr, Dietrich; Neidhart, Sybille; Schieber, Andreas; Carle, Reinhold

2008-06-25

As an alternative to thermal pasteurization, pulsed electric fields (PEF) were applied to apple juices on laboratory and pilot plant scale, investigating the effects on juice quality. PEF application still falls under the EU Novel Food Regulation. Consequently, extensive investigation of quality parameters is a prerequisite to prove substantial equivalence of juices resulting from the novel process and conventional production, respectively. Juice composition was not affected by PEF treatment. However, browning of the juices provided evidence of residual enzyme activities. On laboratory scale, complete deactivation of peroxidase (POD) and polyphenoloxidase (PPO) was achieved when PEF treatment and preheating of the juices to 60 degrees C were combined. Under these conditions, a synergistic effect of heat and PEF was observed. On pilot plant scale, maximum PPO deactivation of 48% was achieved when the juices were preheated to 40 degrees C and PEF-treated at 30 kV/cm (100 kJ/kg). Thus, minimally processed juices resulted from PEF processing, when applied without additional conventional thermal preservation. Since this product type was characterized by residual native enzyme activities and nondetectable levels of 5-hydroxymethylfurfural, also when preheating up to 40 degrees C was included, it ranged between fresh and pasteurized juices regarding consumers' expectation of freshness and shelf life. Consistent with comparable iron contents among all juice samples, no electrode corrosion was observed under the PEF conditions applied.

Ethanol from wood. Cellulase enzyme production

Energy Technology Data Exchange (ETDEWEB)

Szengyel, Zsolt

2000-03-01

Conversion of biomass to liquid fuels, such as ethanol, has been investigated during the past decades. First due to the oil crisis of the 1970s and lately because of concerns about greenhouse effect, ethanol has been found to be a suitable substitute for gasoline in transportation. Although ethanol is produced in large quantities from corn starch, the conversion of lignocellulosic biomass to ethanol is rather problematic. However, cellulosic raw materials are important as they are available in large quantities from agriculture and forestry. One of the most extensively investigated processes is the enzymatic process, in which fungal cellulolytic enzymes are used to convert the cellulose content of the biomass to glucose, which is then fermented to ethanol. In order to make the raw material accessible to biological attack, it has to be pretreated first. The most successful method, which has been evaluated for various lignocellulosic materials, is the steam pretreatment. In this thesis the utilization of steam pretreated willow (hardwood) and spruce (softwood) was examined for enzyme production using a filamentous fungus T. reesei RUT C30. Various carbon sources originating from the steam pretreated materials have been investigated. The replacement of the solid carbon source with a liquid carbon source, as well as the effect of pH, was studied. The effect of toxic compounds generated during pretreatment was also examined. Comparative study of softwood and hardwood showed that steam pretreated hardwood is a better carbon source than softwood. The hydrolytic potential of enzyme solutions produced on wood derived carbon sources was better compared to commercial cellulases. Also enzyme solutions produced on steam pretreated spruce showed less sensitivity towards toxic compounds formed during steam pretreatment.

Integrating enzyme fermentation in lignocellulosic ethanol production: life-cycle assessment and techno-economic analysis.

Science.gov (United States)

Olofsson, Johanna; Barta, Zsolt; Börjesson, Pål; Wallberg, Ola

2017-01-01

Cellulase enzymes have been reported to contribute with a significant share of the total costs and greenhouse gas emissions of lignocellulosic ethanol production today. A potential future alternative to purchasing enzymes from an off-site manufacturer is to integrate enzyme and ethanol production, using microorganisms and part of the lignocellulosic material as feedstock for enzymes. This study modelled two such integrated process designs for ethanol from logging residues from spruce production, and compared it to an off-site case based on existing data regarding purchased enzymes. Greenhouse gas emissions and primary energy balances were studied in a life-cycle assessment, and cost performance in a techno-economic analysis. The base case scenario suggests that greenhouse gas emissions per MJ of ethanol could be significantly lower in the integrated cases than in the off-site case. However, the difference between the integrated and off-site cases is reduced with alternative assumptions regarding enzyme dosage and the environmental impact of the purchased enzymes. The comparison of primary energy balances did not show any significant difference between the cases. The minimum ethanol selling price, to reach break-even costs, was from 0.568 to 0.622 EUR L -1 for the integrated cases, as compared to 0.581 EUR L -1 for the off-site case. An integrated process design could reduce greenhouse gas emissions from lignocellulose-based ethanol production, and the cost of an integrated process could be comparable to purchasing enzymes produced off-site. This study focused on the environmental and economic assessment of an integrated process, and in order to strengthen the comparison to the off-site case, more detailed and updated data regarding industrial off-site enzyme production are especially important.

Action of ionizing radiation on the carbohydrate metabolism enzymes

International Nuclear Information System (INIS)

Cherkasova, L.S.; Mironova, T.M.

1976-01-01

It follows from data reported in literature and those obtained in our laboratory that ionizing radiation does not drastically change the activity of enzymes of the carbohydrate metabolism in tissues of an animal organism. The data are reported on the effect of a whole-body single, fractionated or continuous irradiation of the enzymes of carbohydrate metabolism and the accompanying interrelated co-operative redistributions within the processes of aerobic and anaerobic glycolysis, and the pentose route of their conversion. The dependence of the postirradiation changes in the activity of enzymes on the neuroendocrine system response to irradiation has been demonstrated

Exquisite Enzyme-Fenton Biomimetic Catalysts for Hydroxyl Radical Production by Mimicking an Enzyme Cascade.

Science.gov (United States)

Zhang, Qi; Chen, Shuo; Wang, Hua; Yu, Hongtao

2018-03-14

Hydrogen peroxide (H 2 O 2 ) is a key reactant in the Fenton process. As a byproduct of enzymatic reaction, H 2 O 2 can be obtained via catalytical oxidation of glucose using glucose oxidase in the presence of O 2 . Another oxidation product (gluconic acid) can suitably adjust the microenvironmental pH contributing to the Fe 3+ /Fe 2+ cycle in the Fenton reaction. Enzymes are extremely efficient at catalyzing a variety of reactions with high catalytic activity, substrate specificity, and yields in living organisms. Inspired by the multiple functions of natural multienzyme systems, an exquisite nanozyme-modified α-FeOOH/porous carbon (PC) biomimetic catalyst constructed by in situ growth of glucose oxidase-mimicking Au nanoparticles and crystallization of adsorbed ferric ions within carboxyl into hierarchically PC is developed as an efficient enzyme-Fenton catalyst. The products (H 2 O 2 , ∼4.07 mmol·L -1 ) of the first enzymatic reaction are immediately used as substrates for the second Fenton-like reaction to generate the valuable • OH (∼96.84 μmol·L -1 ), thus mimicking an enzyme cascade pathway. α-FeOOH nanocrystals, attached by C-O-Fe bondings, are encapsulated into the mesoporous PC frameworks, facilitating the electron transfer between α-FeOOH and the PC support and greatly suppressing iron leaching. This study paves a new avenue for designing biomimetic enzyme-based Fenton catalysts mimicking a natural system for • OH production.

Role of CA-EDTA on the Synthesizing Process of Cerate-Zirconate Ceramics Electrolyte

Directory of Open Access Journals (Sweden)

Nur Athirah Abdullah

2013-01-01

Full Text Available The role of a combination between citric acid (CA and ethylenediaminetetra acetic acid (EDTA as chelating agents in preparation of BaCe0.54Zr0.36Y0.1O2.95 powder by a modified sol-gel method is reported. The precursor solutions were prepared from metal nitrate salts (M+, chelating agents (C, and ethylene glycol (EG at molar ratio of M+ : C : EG = 3 : 2 : 3. Chemical and phase transformation of samples during thermal decomposition were analyzed by thermogravimetric analysis (TGA and Fourier transform infrared (FTIR spectroscopy. TGA results show that the sample prepared by a combination of CA-EDTA exhibited the lowest thermal decomposition temperature, Ttd since there was no significant weight loss after 750°C. After calcined at 1100°C, the carbonates residue remained in the samples as proven by FTIR results. It was found that the used combination of CA-EDTA acts as a better combustion reagent to increase the reaction rate and influence the thermal decomposition behaviour compared to a single citric acid and EDTA, respectively. Apparently, calcination temperatures above 1100°C are needed to produce a pure perovskitic BaCe0.54Zr0.36Y0.1O2.95.

Optimization of ultrasound-assisted extraction of pectinase enzyme from guava (Psidium guajava) peel: Enzyme recovery, specific activity, temperature, and storage stability.

Science.gov (United States)

Amid, Mehrnoush; Murshid, Fara Syazana; Manap, Mohd Yazid; Islam Sarker, Zaidul

2016-01-01

This study aimed to investigate the effects of the ultrasound-assisted extraction conditions on the yield, specific activity, temperature, and storage stability of the pectinase enzyme from guava peel. The ultrasound variables studied were sonication time (10-30 min), ultrasound temperature (30-50 °C), pH (2.0-8.0), and solvent-to-sample ratio (2:1 mL/g to 6:1 mL/g). The main goal was to optimize the ultrasound-assisted extraction conditions to maximize the recovery of pectinase from guava peel with the most desirable enzyme-specific activity and stability. Under the optimum conditions, a high yield (96.2%), good specific activity (18.2 U/mg), temperature stability (88.3%), and storage stability (90.3%) of the extracted enzyme were achieved. The optimal conditions were 20 min sonication time, 40 °C temperature, at pH 5.0, using a 4:1 mL/g solvent-to-sample ratio. The study demonstrated that optimization of ultrasound-assisted process conditions for the enzyme extraction could improve the enzymatic characteristics and yield of the enzyme.

Enzymes for ecdysteroid biosynthesis: their biological functions in insects and beyond.

Science.gov (United States)

Niwa, Ryusuke; Niwa, Yuko S

2014-01-01

Steroid hormones are responsible for the coordinated regulation of many aspects of biological processes in multicellular organisms. Since the last century, many studies have identified and characterized steroidogenic enzymes in vertebrates, including mammals. However, much less is known about invertebrate steroidogenic enzymes. In the last 15 years, a number of steroidogenic enzymes and their functions have been characterized in ecdysozoan animals, especially in the fruit fly Drosophila melanogaster. In this review, we summarize the latest knowledge of enzymes crucial for synthesizing ecdysteroids, the principal insect steroid hormones. We also discuss the functional conservation and diversity of ecdysteroidogenic enzymes in other insects and even non-insect species, such as nematodes, vertebrates, and lower eukaryotes.

Production of lysosomal enzymes in plant-based expression systems

OpenAIRE

1996-01-01

The invention relates to the production of enzymatically active recombinant human and animal lysosomal enzymes involving construction and expression of recombinant expression constructs comprising coding sequences of human or animal lysosomal enzymes in a plant expression system. The plant expression system provides for post-translational modification and processing to produce a recombinant gene product exhibiting enzymatic activity. The invention is demonstrated by working examples in which ...

7 CFR 58.436 - Rennet, pepsin, other milk clotting enzymes and flavor enzymes.

Science.gov (United States)

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Rennet, pepsin, other milk clotting enzymes and flavor enzymes. 58.436 Section 58.436 Agriculture Regulations of the Department of Agriculture (Continued... clotting enzymes and flavor enzymes. Enzyme preparations used in the manufacture of cheese shall be safe...

Bio-functionalization of conductive textile materials with redox enzymes

Science.gov (United States)

Kahoush, M.; Behary, N.; Cayla, A.; Nierstrasz, V.

2017-10-01

In recent years, immobilization of oxidoreductase enzymes on electrically conductive materials has played an important role in the development of sustainable bio-technologies. Immobilization process allows the re-use of these bio-catalysts in their final applications. In this study, different methods of immobilizing redox enzymes on conductive textile materials were used to produce bio-functionalized electrodes. These electrodes can be used for bio-processes and bio-sensing in eco-designed applications in domains such as medicine and pollution control. However, the main challenge facing the stability and durability of these electrodes is the maintenance of the enzymatic activity after the immobilization. Hence, preventing the enzyme’s denaturation and leaching is a critical factor for the success of the immobilization processes.

Elevated Liver Enzymes

Science.gov (United States)

Symptoms Elevated liver enzymes By Mayo Clinic Staff Elevated liver enzymes may indicate inflammation or damage to cells in the liver. Inflamed or ... than normal amounts of certain chemicals, including liver enzymes, into the bloodstream, which can result in elevated ...

Stability of Enzymes in Granular Enzyme Products for Laundry Detergents

DEFF Research Database (Denmark)

Biran, Suzan; Bach, Poul; Simonsen, Ole

Enzymes have long been of interest to the detergent industry due to their ability to improve the cleaning efficiency of synthetic detergents, contribute to shortening washing times, and reduce energy and water consumption, provision of environmentally friendlier wash water effluents and fabric care....... However, incorporating enzymes in detergent formulations gives rise to numerous practical problems due to their incompatibility with and stability against various detergent components. In powdered detergent formulations, these issues can be partly overcome by physically isolating the enzymes in separate...... particles. However, enzymes may loose a significant part of their activity over a time period of several weeks. Possible causes of inactivation of enzymes in a granule may be related to the release of hydrogen peroxide from the bleaching chemicals in a moisture-containing atmosphere, humidity, autolysis...

Coproduction of detergent compatible bacterial enzymes and stain removal evaluation.

Science.gov (United States)

Niyonzima, Francois N; More, Sunil S

2015-10-01

Most of the detergents that are presently produced contain the detergent compatible enzymes to improve and accelerate the washing performance by removing tough stains. The process is environment friendly as the use of enzymes in the detergent formulation reduces the utilization of toxic detergent constituents. The current trend is to use the detergent compatible enzymes that are active at low and ambient temperature in order to save energy and maintain fabric quality. As the detergent compatible bacterial enzymes are used together in the detergent formulation, it is important to co-produce the detergent enzymes in a single fermentation medium as the enzyme stability is assured, and production cost gets reduced enormously. The review reports on the production, purification, characterization and application of detergent compatible amylases, lipases, and proteases are available. However, there is no specific review or minireview on the concomitant production of detergent compatible amylases, lipases, and proteases. In this minireview, the coproduction of detergent compatible enzymes by bacterial species, enzyme stability towards detergents and detergent components, and stain release analysis were discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Potential and utilization of thermophiles and thermostable enzymes in biorefining

Directory of Open Access Journals (Sweden)

Karlsson Eva

2007-03-01

Full Text Available Abstract In today's world, there is an increasing trend towards the use of renewable, cheap and readily available biomass in the production of a wide variety of fine and bulk chemicals in different biorefineries. Biorefineries utilize the activities of microbial cells and their enzymes to convert biomass into target products. Many of these processes require enzymes which are operationally stable at high temperature thus allowing e.g. easy mixing, better substrate solubility, high mass transfer rate, and lowered risk of contamination. Thermophiles have often been proposed as sources of industrially relevant thermostable enzymes. Here we discuss existing and potential applications of thermophiles and thermostable enzymes with focus on conversion of carbohydrate containing raw materials. Their importance in biorefineries is explained using examples of lignocellulose and starch conversions to desired products. Strategies that enhance thermostablity of enzymes both in vivo and in vitro are also assessed. Moreover, this review deals with efforts made on developing vectors for expressing recombinant enzymes in thermophilic hosts.

Furin is a chemokine-modifying enzyme

DEFF Research Database (Denmark)

Hensbergen, Paul J; Verzijl, Dennis; Balog, Crina I A

2004-01-01

Chemokines comprise a class of structurally related proteins that are involved in many aspects of leukocyte migration under basal and inflammatory conditions. In addition to the large number of genes, limited processing of these proteins by a variety of enzymes enhances the complexity of the tota...

Multivariate Statistical Process Optimization in the Industrial Production of Enzymes

DEFF Research Database (Denmark)

Klimkiewicz, Anna

of productyield. The potential of NIR technology to monitor the activity of the enzyme has beenthe subject of a feasibility study presented in PAPER I. It included (a) evaluation onwhich of the two real-time NIR flow cell configurations is the preferred arrangementfor monitoring of the retentate stream downstream...... strategies for theorganization of these datasets, with varying number of timestamps, into datastructures fit for latent variable (LV) modeling, have been compared. The ultimateaim of the data mining steps is the construction of statistical ‘soft models’ whichcapture the principle or latent behavior...

Enzyme structure, enzyme function and allozyme diversity in ...

African Journals Online (AJOL)

In estimates of population genetic diversity based on allozyme heterozygosity, some enzymes are regularly more variable than others. Evolutionary theory suggests that functionally less important molecules, or parts of molecules, evolve more rapidly than more important ones; the latter enzymes should then theoretically be ...

Remote enzyme activation using gold coated magnetite as antennae for radio frequency fields

Science.gov (United States)

Collins, Christian B.; Ackerson, Christopher J.

2018-02-01

The emerging field of remote enzyme activation, or the ability to remotely turn thermophilic increase enzyme activity, could be a valuable tool for understanding cellular processes. Through exploitation of the temperature dependence of enzymatic processes and high thermal stability of thermophilic enzymes these experiments utilize nanoparticles as `antennae' that convert radiofrequency (RF) radiation into local heat, increasing activity of the enzymes without increasing the temperature of the surrounding bulk solution. To investigate this possible tool, thermolysin, a metalloprotease was covalently conjugated to 4nm gold coated magnetite particles via peptide bond formation with the protecting ligand shell. RF stimulated protease activity at 17.76 MHz in a solenoid shaped antenna, utilizing both electric and magnetic field interactions was investigated. On average 40 percent higher protease activity was observed in the radio frequency fields then when bulk heating the sample to the same temperature. This is attributed to electrophoretic motion of the nanoparticle enzyme conjugates and local regions of heat generated by the relaxation of the magnetite cores with the oscillating field. Radio frequency local heating of nanoparticles conjugated to enzymes as demonstrated could be useful in the activation of specific enzymes in complex cellular environments.

High Pressure Homogenization of Porcine Pepsin Protease: Effects on Enzyme Activity, Stability, Milk Coagulation Profile and Gel Development

Science.gov (United States)

Leite Júnior, Bruno Ricardo de Castro; Tribst, Alline Artigiani Lima; Cristianini, Marcelo

2015-01-01

This study investigated the effect of high pressure homogenization (HPH) (up to 190 MPa) on porcine pepsin (proteolytic and milk-clotting activities), and the consequences of using the processed enzyme in milk coagulation and gel formation (rheological profile, proteolysis, syneresis, and microstructure). Although the proteolytic activity (PA) was not altered immediately after the HPH process, it reduced during enzyme storage, with a 5% decrease after 60 days of storage for samples obtained with the enzyme processed at 50, 100 and 150 MPa. HPH increased the milk-clotting activity (MCA) of the enzyme processed at 150 MPa, being 15% higher than the MCA of non-processed samples after 60 days of storage. The enzyme processed at 150 MPa produced faster aggregation and a more consistent milk gel (G’ value 92% higher after 90 minutes) when compared with the non-processed enzyme. In addition, the gels produced with the enzyme processed at 150 MPa showed greater syneresis after 40 minutes of coagulation (forming a more compact protein network) and lower porosity (evidenced by confocal microscopy). These effects on the milk gel can be associated with the increment in MCA and reduction in PA caused by the effects of HPH on pepsin during storage. According to the results, HPH stands out as a process capable of changing the proteolytic characteristics of porcine pepsin, with improvements on the milk coagulation step and gel characteristics. Therefore, the porcine pepsin submitted to HPH process can be a suitable alternative for the production of cheese. PMID:25938823

Effects of particle size of processed barley grain, enzyme addition and microwave treatment on in vitro disappearance and gas production for feedlot cattle.

Science.gov (United States)

Tagawa, Shin-Ichi; Holtshausen, Lucia; McAllister, Tim A; Yang, Wen Zhu; Beauchemin, Karen Ann

2017-04-01

The effects of particle size of processed barley grain, enzyme addition and microwave treatment on in vitro dry matter (DM) disappearance (DMD), gas production and fermentation pH were investigated for feedlot cattle. Rumen fluid from four fistulated feedlot cattle fed a diet of 860 dry-rolled barley grain, 90 maize silage and 50 supplement g/kg DM was used as inoculum in 3 batch culture in vitro studies. In Experiment 1, dry-rolled barley and barley ground through a 1-, 2-, or 4-mm screen were used to obtain four substrates differing in particle size. In Experiment 2, cellulase enzyme (ENZ) from Acremonium cellulolyticus Y-94 was added to dry-rolled and ground barley (2-mm) at 0, 0.1, 0.5, 1, and 2 mg/g, while Experiment 3 examined the interactions between microwaving (0, 30, and 60 s microwaving) and ENZ addition (0, 1, and 2 mg/g) using dry-rolled barley and 2-mm ground barley. In Experiment 1, decreasing particle size increased DMD and gas production, and decreased fermentation pH (pgas production and decreased (pgas production, and decreased (p<0.05) fermentation pH of dry-rolled barley, but not ground barley. We conclude that cellulase enzymes can be used to increase the rumen disappearance of barley grain when it is coarsely processed as in the case of dry-rolled barley. However, microwaving of barley grain offered no further improvements in ruminal fermentation of barley grain.

Enhancement of Palm Oil Extraction Using Cell Wall Degrading Enzyme Formulation

International Nuclear Information System (INIS)

Silvamany, H.; Jamaliah Md Jahim

2015-01-01

In this recent work, application of aqueous enzymatic process to enhance recovery of palm oil was studied. Experiments were carried out to investigate the structural carbohydrate composition of oil palm mesocarp (Elaeis guineensis) and to analyze the effect of different combination of enzymes on the palm oil recovery and degree of digestibility and the respective correlation. The optimum combination of enzymes comprising of Cellic CTec2 (X 1 ), Cellic HTec2 (X 2 ) and Pectinex Ultra SP-L (X 3 ) for Aqueous Enzymatic Oil Extraction Process (AEOEP), were determined using Simplex Lattice mixture design under fixed parameters. Maximum oil recovery of 88 % was achieved with ratio of enzymes at 0.46: 0.34: 0.2 (X 1 :X 2 :X 3 ), at enzyme loading of 30 mg protein/ 10 g substrate, substrate loading of 50 % w/v, pH 4.8, and 2 hours of incubation at 50 degree Celsius. The conversion of reducing sugar at corresponding condition was measured to evaluate the effectiveness of enzymes in degrading fruit cell wall releasing trapped oil. Moreover, transmission electron microscopy (TEM) was utilized to indicate the increase in cell wall disintegration leading to higher release of oil with enzymatic treatment. (author)

Laccase Enzymes in Inocula Pleurotus spp

Directory of Open Access Journals (Sweden)

Nora García-Oduardo

2017-01-01

Full Text Available The cultivation of edible and medicinal mushrooms Pleurotus has been aimed at promoting alternative management for agricultural products. This basidiomicete has been the subject of numerous studies because of its fruiting body constitutes a food, being a producer of enzymes with industrial interest and for its ability of biotransformation of lignocellulosic substrates. Pleurotus inocula in the established technology for growing edible and medicinal mushrooms in the CEBI Research- Production Plant were performed using sorghum or wheat. However, it is possible to expand the possibilities with other substrates. In this paper, the results of laccase enzymes production in inocula prepared with sorghum, corn and coffee pulp with two strains Pleurotus ostreatus CCEBI 3021 and Pleurotus ostreatus CCEBI 3024 are presented. The period of preparation of seed reaches 15-21 days, the measurements of laccase activity were performed in periods of seven days. Extraction of crude enzyme was performed in aqueous phase, the determination of the laccase enzyme activity, using guaiacol as substrate. The results obtained in this work with studies in previous work using sorghum as inocula are compared. It is found that higher yields are obtained laccase in coffee pulp. This study contributes to the theoretical knowledge and to provide alternatives for securing the production process of the plant.

Research Applications of Proteolytic Enzymes in Molecular Biology

Directory of Open Access Journals (Sweden)

József Tőzsér

2013-11-01

Full Text Available Proteolytic enzymes (also termed peptidases, proteases and proteinases are capable of hydrolyzing peptide bonds in proteins. They can be found in all living organisms, from viruses to animals and humans. Proteolytic enzymes have great medical and pharmaceutical importance due to their key role in biological processes and in the life-cycle of many pathogens. Proteases are extensively applied enzymes in several sectors of industry and biotechnology, furthermore, numerous research applications require their use, including production of Klenow fragments, peptide synthesis, digestion of unwanted proteins during nucleic acid purification, cell culturing and tissue dissociation, preparation of recombinant antibody fragments for research, diagnostics and therapy, exploration of the structure-function relationships by structural studies, removal of affinity tags from fusion proteins in recombinant protein techniques, peptide sequencing and proteolytic digestion of proteins in proteomics. The aim of this paper is to review the molecular biological aspects of proteolytic enzymes and summarize their applications in the life sciences.

Molecular Imaging of Hydrolytic Enzymes Using PET and SPECT

OpenAIRE

Rempel, Brian P.; Price, Eric W.; Phenix, Christopher P.

2017-01-01

Hydrolytic enzymes are a large class of biological catalysts that play a vital role in a plethora of critical biochemical processes required to maintain human health. However, the expression and/or activity of these important enzymes can change in many different diseases and therefore represent exciting targets for the development of positron emission tomography (PET) and single-photon emission computed tomography (SPECT) radiotracers. This review focuses on recently reported radiolabeled sub...

Statistical Mechanics Analysis of ATP Binding to a Multisubunit Enzyme

International Nuclear Information System (INIS)

Zhang Yun-Xin

2014-01-01

Due to inter-subunit communication, multisubunit enzymes usually hydrolyze ATP in a concerted fashion. However, so far the principle of this process remains poorly understood. In this study, from the viewpoint of statistical mechanics, a simple model is presented. In this model, we assume that the binding of ATP will change the potential of the corresponding enzyme subunit, and the degree of this change depends on the state of its adjacent subunits. The probability of enzyme in a given state satisfies the Boltzmann's distribution. Although it looks much simple, this model can fit the recent experimental data of chaperonin TRiC/CCT well. From this model, the dominant state of TRiC/CCT can be obtained. This study provide a new way to understand biophysical processe by statistical mechanics analysis. (interdisciplinary physics and related areas of science and technology)

Development and process optimization of an enzyme membrane reactor for lactose hydrolysis. Entwicklung und verfahrenstechnische Optimierung eines Enzym-Membranreaktors fuer die Hydrolyse von Laktose

Energy Technology Data Exchange (ETDEWEB)

Czermak, P

1990-01-01

The development and process optimization up to the production stage of a vapour sterilizable hollow-fiber membrane reactor for dialysis is illustrated by the example of enzymatic hydrolysis of lactose. The expected conversion efficiency of the membrane reactor is a function of the mass transfer resistance and by the deviations from the defined hydrodynamic status. The transport/reaction behaviour of membrane reactors is therefore described by a model for real reactors which takes account of the non-linear kinetics of the native enzyme, the real mixing conditions inside the reactor, and the mass transfer through the membrane. A coupled numerical solution is used for the calculations. The reaction kinetics, the mass transfer inside the membrane, the hydrodynamics and the conversion rate are determined experimentally. The model can calculate important design data from selected data of the reaction system. Measurements of conversion rates show that the results obtained with real substances, e.g. milk, are well compatible with the model calculations. (orig.) With 85 figs., 25 tabs.

Visualization of Enzyme Activities in Earthworm Biopores by In Situ Soil Zymography.

Science.gov (United States)

Razavi, Bahar S; Hoang, Duyen; Kuzyakov, Yakov

2017-01-01

Earthworms produce biopores with strongly increased microbial and enzyme activities and consequently they form microbial hotspots in soil. In extremely dynamic microhabitats and hotspots such as earthworm biopores, the in situ enzyme activities are a footprint of process rates and complex biotic interactions. The effect of earthworms on enzyme activities inside biopores, relative to earthworm-free soil, can be visualized by in situ soil zymography. Here, we describe the details of the approach and discuss its advantages and limitations. Direct zymography provides high spatial resolution for quantitative images of enzyme activities in biopores.

Molecular dynamics simulations of deoxyribonucleic acids and repair enzyme T4 endonuclease V

International Nuclear Information System (INIS)

Pinak, Miroslav

1999-01-01

This report describes the results of molecular dynamics (MD) simulation of deoxyribonucleic acids (DNA) and specific repair enzyme T4 endonuclease V. Namely research described here is focused on the examination of specific recognition process, in which this repair enzyme recognizes the damaged site on the DNA molecule-thymine dimer (TD). TD is frequent DNA damage induced by UV radiation in sun light and unless properly repaired it may be mutagenic or lethal for cell, and is also considered among the major causes of skin cancer. T4 endonuclease V is a DNA specific repair enzyme from bacteriophage T4 that catalyzes the first reaction step of TD repair pathway. MD simulations of three molecules - native DNA dodecamer (12 base pairs), DNA of the same sequence of nucleotides as native one but with TD, and repair enzyme T4 endonuclease V - were performed for 1 ns individually for each molecule. Simulations were analyzed to determine the role of electrostatic interaction in the recognition process. It is found that electrostatic energies calculated for amino acids of the enzyme have positive values of around +15 kcal/mol. The electrostatic energy of TD site has negative value of approximately -9 kcal/mol, different from the nearly neutral value of the respective thymines site of the native DNA. The electrostatic interaction of TD site with surrounding water environment differs from the electrostatic interaction of other nucleotides. Differences found between TD site and respective thymines site of native DNA indicate that the electrostatic energy is an important factor contributing to proper recognition of TD site during scanning process in which enzyme scans the DNA. In addition to the electrostatic energy, the important factor in recognition process might be structural complementarity of enzyme and bent DNA with TD. There is significant kink formed around TD site, that is not observed in native DNA. (author)

Translational control of an intestinal microvillar enzyme

DEFF Research Database (Denmark)

Danielsen, E M; Cowell, G M; Sjöström, H

1986-01-01

The rates of biosynthesis of adult and foetal pig small-intestinal aminopeptidase N (EC 3.4.11.2) were compared to determine at which level the expression of the microvillar enzyme is developmentally controlled. In organ-cultured explants, the rate of biosynthesis of foetal aminopeptidase N is only...... about 3% of the adult rate. The small amount synthesized occurs in a high-mannose-glycosylated, membrane-bound, form that is processed to the mature, complex-glycosylated, form at a markedly slower rate than that of the adult enzyme. Extracts of total RNA from adult and foetal intestine contained...

Enzyme kinetic characterization of protein tyrosine phosphatases

DEFF Research Database (Denmark)

Peters, Günther H.J.; Branner, S.; Møller, K. B.

2003-01-01

Protein tyrosine phosphatases (PTPs) play a central role in cellular signaling processes, resulting in an increased interest in modulating the activities of PTPs. We therefore decided to undertake a detailed enzyme kinetic evaluation of various transmembrane and cytosolic PTPs (PTPalpha, PTPbeta...

Enzymes for Enhanced Oil Recovery (EOR)

Energy Technology Data Exchange (ETDEWEB)

Nasiri, Hamidreza

2011-04-15

enzymes on interactions in the oil/brine/solid system was studied. It was found that enzymes can change the adhesion behavior of the crude oil on glass surfaces from adhesion to non-adhesion when they are added to the brine solution. This was confirmed by contact angle measurements, which showed that contact angles became more water-wet (i.e. decreased) after exposure to enzyme solutions. Possible mechanisms giving rise to these observations, including catalysis of ester hydrolysis and enzyme adsorption, were discussed and tested. An experimental study of changes in oil-water interfacial properties by addition of enzymes and proteins, including measurements of interfacial tension and electrophoretic mobility, has been performed. It was found that the effect of enzymes on oil-water properties is minor compared to their effect on oil-water-solid properties. Their contribution to change interfacial tension between oil and water is not significant while they affect the electrophoretic mobility of emulsified oil in enzyme-brine solution to some extent. Attempts were also made to study changes in both oil and water phase composition after equilibration with enzymes. However, since the chemical composition of crude oil is highly complex, a model oil was used in some of the experiments. The model oil was chosen to be a water insoluble ester (ethyl decanoate) solved in mineral oil in an effort to verify the possible role of catalysis of ester hydrolysis. Dynamic core displacements using sandstone and carbonate rocks were conducted to show the potential of improved oil recovery by enzyme- and combined enzyme-surfactant flooding. Most of the core flooding experiments commenced with water flooding from initial water saturation, Swi, (established with synthetic sea water) which will be referred to as secondary mode displacements. Accordingly, tertiary oil recovery processes were used to describe injection of enzyme and/or enzyme-surfactant solutions from residual oil saturation, Sor

Expanding the Halohydrin Dehalogenase Enzyme Family: Identification of Novel Enzymes by Database Mining.

Science.gov (United States)

Schallmey, Marcus; Koopmeiners, Julia; Wells, Elizabeth; Wardenga, Rainer; Schallmey, Anett

2014-12-01

Halohydrin dehalogenases are very rare enzymes that are naturally involved in the mineralization of halogenated xenobiotics. Due to their catalytic potential and promiscuity, many biocatalytic reactions have been described that have led to several interesting and industrially important applications. Nevertheless, only a few of these enzymes have been made available through recombinant techniques; hence, it is of general interest to expand the repertoire of these enzymes so as to enable novel biocatalytic applications. After the identification of specific sequence motifs, 37 novel enzyme sequences were readily identified in public sequence databases. All enzymes that could be heterologously expressed also catalyzed typical halohydrin dehalogenase reactions. Phylogenetic inference for enzymes of the halohydrin dehalogenase enzyme family confirmed that all enzymes form a distinct monophyletic clade within the short-chain dehydrogenase/reductase superfamily. In addition, the majority of novel enzymes are substantially different from previously known phylogenetic subtypes. Consequently, four additional phylogenetic subtypes were defined, greatly expanding the halohydrin dehalogenase enzyme family. We show that the enormous wealth of environmental and genome sequences present in public databases can be tapped for in silico identification of very rare but biotechnologically important biocatalysts. Our findings help to readily identify halohydrin dehalogenases in ever-growing sequence databases and, as a consequence, make even more members of this interesting enzyme family available to the scientific and industrial community. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Temperature sensitivity of extracellular enzyme kinetics in subtropical wetland soils under different nutrient and water level conditions

Science.gov (United States)

Goswami, S.; Inglett, K.; Inglett, P.

2012-12-01

Microbial extracellular enzymes play an important role in the initial steps of soil organic matter decomposition and are involved in regulating nutrient cycle processes. Moreover, with the recent concern of climate change, microbial extracellular enzymes may affect the functioning (C losses, C sequestration, greenhouse gas emissions, vegetation changes) of different ecosystems. Hence, it is imperative to understand the biogeochemical processes that may be climate change sensitive. Here, we have measured the Michaelis Menten Kinetics [maximal rate of velocity (Vmax) and half-saturation constant (Km)] of 6 enzymes involved in soil organic matter decomposition (phosphatase, phosphodiesterase, β-D-glucosidase, cellobiohydrolase, leucine aminopeptidase, N-Acetyl-β-D glucosaminidase) in different nutrient(P) concentration both aerobically and anaerobically in Everglade water conservation area 2A (F1, F4-slough and U3-slough). Temperature sensitivity of different enzymes is assessed within soil of different P concentrations. We hypothesized that the temperature sensitivity of the enzyme changes with the biogeochemical conditions including water level and nutrient condition. Furthermore, we have tested specific hypothesis that higher P concentration will initiate more C demand for microbes leading to higher Vmax value for carbon processing enzymes in high P site. We found temperature sensitivity of all enzymes for Vmax and Km under both aerobic and anaerobic condition ranges from 0.6 to 3.2 for Vmax and 0.5 to 2.5 for Km. Q10 values of Km for glucosidase indicate more temperature sensitivity under anaerobic condition. Under aerobic condition higher temperature showed significant effect on Vmax for bisphosphatase between high P and low P site. Decreasing P concentration from F1 site to U3-S site had showed significant effect in all temperature on carbon processing enzyme. This suggests that in high P site, microbes will use more carbon-processing enzyme to get more carbon

On-Site Enzyme Production by Trichoderma asperellum for the Degradation of Duckweed

DEFF Research Database (Denmark)

Bech, Lasse; Herbst, Florian-Alexander; Grell, Morten Nedergaard

2015-01-01

The on-site production of cell wall degrading enzymes is an important strategy for the development of sustainable bio-refinery processes. This study concerns the optimization of production of plant cell wall-degrading enzymes produced by Trichoderma asperellum. A comparative secretome analysis...

EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2014. Scientific Opinion on xylanase from a genetically modified strain of Aspergillus oryzae (strain NZYM-FB)

DEFF Research Database (Denmark)

Poulsen, Morten; Binderup, Mona-Lise; Hallas-Møller, Torben

. The xylanase is intended to be used in a number of food manufacturing processes, such as starch processing, beverage alcohol (distilling), brewing, baking and other cereal based processes. The dietary exposure was assessed according to the Budget method. The food enzyme did not induce gene mutations...

Metagenomics as a Tool for Enzyme Discovery: Hydrolytic Enzymes from Marine-Related Metagenomes.

Science.gov (United States)

Popovic, Ana; Tchigvintsev, Anatoly; Tran, Hai; Chernikova, Tatyana N; Golyshina, Olga V; Yakimov, Michail M; Golyshin, Peter N; Yakunin, Alexander F

2015-01-01

This chapter discusses metagenomics and its application for enzyme discovery, with a focus on hydrolytic enzymes from marine metagenomic libraries. With less than one percent of culturable microorganisms in the environment, metagenomics, or the collective study of community genetics, has opened up a rich pool of uncharacterized metabolic pathways, enzymes, and adaptations. This great untapped pool of genes provides the particularly exciting potential to mine for new biochemical activities or novel enzymes with activities tailored to peculiar sets of environmental conditions. Metagenomes also represent a huge reservoir of novel enzymes for applications in biocatalysis, biofuels, and bioremediation. Here we present the results of enzyme discovery for four enzyme activities, of particular industrial or environmental interest, including esterase/lipase, glycosyl hydrolase, protease and dehalogenase.

Treatment of wastewaters containing anilines using enzymes: an overview

International Nuclear Information System (INIS)

Mantha, R.; Biswas, N.; Taylor, K.E.; Bewtra, J.K.

2002-01-01

Aromatic amines are manufactured in a large scale for use in industries dealing with resins, dyes, plastics and rubber, pesticides and explosives. The majority of the production-related waste is either incinerated or released into the environment. The majority of them are highly toxic, carcinogenic or mutagenic and impose serious health hazards to mankind. Available conventional physical-chemical processes including activated carbon adsorption processes, solvent extraction processes, microbial degradation and various chemical-oxidation processes developed over the years are not selective in terms of the range of the aromatic pollutant removed during treatment. Thus, such treatment strategies are more economically suitable for treatment of dilute wastewaters and are invariably used as polishing steps. Enzymes such as peroxidases, in the presence of hydrogen peroxide, and laccases, in the presence of oxygen, catalyze the oxidation of a wide variety of phenols, biphenyls, anilines, benzidines and other related aromatic compounds. Various peroxidases and laccases have been used to treat wastewaters. With respect to anilines, the potential, scope and cost of enzymatic treatment is reviewed here and compared with conventional technology, e.g., the cost of enzymatic treatment using a crude enzyme preparation of soybean peroxidase was reported to be about $0.36/m 3 for synthetic wastewater containing 1 mM of aniline, compared to an activated sludge process of $1.05/m 3 and $1.31/m 3 for activated carbon process, while for p-toluidine, it was about $0.17/m 3 . Thus, through choice of enzyme and its mode of operation, treatment costs less than the conventional treatment strategies can be achieved. (author)

SCREENING OF THERMOPHYLIC MICROORGANISM FROM IJEN CRATER BANYUWANGI AS PHYTASE ENZYME PRODUCER

Directory of Open Access Journals (Sweden)

Aline Puspita Kusumadjaja

2010-06-01

Full Text Available Phytase is enzyme which hydrolysis phytic acid to anorganic phosphate and myo-inositol pentakis-, tetrakis-, tris-, bis-, and monophosphate. The use of phytase in feed industry can overcome environment and nutrition problems which were arisen from unmetabolism phytic acid or its salt by poultry, swine and fish. The feed industry needs a thermostable enzyme due to the need of high temperature in pelleting process, i.e. 81 °C. By using thermostabile phytase, the pelleting process will not affect the enzyme activity. Thermostabile phytase can be isolated from microorganism live in hot spring water or volcano crater. In this study, the screening of thermophylic microorganism having thermostabile phytase activity in Ijen Crater, Banyuwangi, has been done. From this process, it was obtained 33 isolates that produce phytase enzyme. Isolate was code by AP-17 yields highest phytase activity, that is 0.0296 U/mL, so this isolate was choosen for further study. The activity of crude phytase enzyme was measured based on the amount of anorganic phosphate that was produced in enzymatic reaction using UV-VIS spectrophotometer at 392 nm. Based on morphology test to identify the gram type of microorganism, isolate AP-17 has a bacill cell type and identified as positive gram bacteria. This isolate was assumed as Bacillus type.   Keywords: Phytase, thermophilic microorganism, phytase activity

Enzymes and Enzyme Activity Encoded by Nonenveloped Viruses.

Science.gov (United States)

Azad, Kimi; Banerjee, Manidipa; Johnson, John E

2017-09-29

Viruses are obligate intracellular parasites that rely on host cell machineries for their replication and survival. Although viruses tend to make optimal use of the host cell protein repertoire, they need to encode essential enzymatic or effector functions that may not be available or accessible in the host cellular milieu. The enzymes encoded by nonenveloped viruses-a group of viruses that lack any lipid coating or envelope-play vital roles in all the stages of the viral life cycle. This review summarizes the structural, biochemical, and mechanistic information available for several classes of enzymes and autocatalytic activity encoded by nonenveloped viruses. Advances in research and development of antiviral inhibitors targeting specific viral enzymes are also highlighted.

Dexibuprofen prevents neurodegeneration and cognitive decline in APPswe/PS1dE9 through multiple signaling pathways

Directory of Open Access Journals (Sweden)

Miren Ettcheto

2017-10-01

Full Text Available The aim of the present study is to elucidate the neuronal pathways associated to NSAIDs causing a reduction of the risk and progression of Alzheimer's disease. The research was developed administering the active enantiomer of ibuprofen, dexibuprofen (DXI, in order to reduce associated gastric toxicity. DXI was administered from three to six-month-old female APPswe/PS1dE9 mice as a model of familial Alzheimer's disease. DXI treatment reduced the activation of glial cells and the cytokine release involved in the neurodegenerative process, especially TNFα. Moreover, DXI reduced soluble β-amyloid (Aβ1-42 plaque deposition by decreasing APP, BACE1 and facilitating Aβ degradation by enhancing insulin-degrading enzyme. DXI also decreased TAU hyperphosphorylation inhibiting c-Abl/CABLES/p-CDK5 activation signal pathway and prevented spatial learning and memory impairment in transgenic mice. Therefore, chronic DXI treatment could constitute a potential AD-modifying drug, both restoring cognitive functions and reversing multiple brain neuropathological hallmarks.

An enzyme to improve the ethanol production; Une enzyme pour ameliorer la production d'ethanol

Energy Technology Data Exchange (ETDEWEB)

Anon.

2005-07-01

The American firm Genecor launches a technology which allows to improve the production of ethanol from agricultural resources. This technology involves in particular a decrease of the energy consumption and of the production costs and a best yield. In the process, is used a mixture of enzymes composed of alpha-amylase and gluco-amylase. (O.M.)

Hydrolytic enzyme activity enhanced by Barium supplementation

Directory of Open Access Journals (Sweden)

Camilo Muñoz

2016-10-01

Full Text Available Hydrolysis of polymers is a first and often limiting step during the degradation of plant residues. Plant biomass is generally a major component of waste residues and a major renewable resource to obtain a variety of secondary products including biofuels. Improving the performance of enzymatic hydrolysis of plant material with minimum costs and limiting the use of additional microbial biomass or hydrolytic enzymes directly influences competitiveness of these green biotechnological processes. In this study, we cloned and expressed a cellulase and two esterases recovered from environmental thermophilic soil bacterial communities and characterize their optimum activity conditions including the effect of several metal ions. Results showed that supplementing these hydrolytic reactions with Barium increases the activity of these extracellular hydrolytic enzymes. This observation represents a simple but major improvement to enhance the efficiency and competitiveness of this process within an increasingly important biotechnological sector.

Little enzyme; Shoryo no tobun ga koso wo kappatsuka

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-06-05

It was discovered that the enzymatic heat-resistance increased by the addition of the trehalose in which the researcher of Institute of Physical and Chemical Research (it is given) is one of the disaccharides to the enzyme process. By this, it becomes possible that enzyme reaction is more promoted under the high temperature. They obtained this idea, because the yeast formed the trehalose over the room temperature for the protection of self it. In the example of some enzyme reaction, the about 20 times the speed has been obtained under 60 degrees C in comparison with the under ordinary temperature. Too the similar example has mainly been otherwise accepted. (translated by NEDO)

Ultrasound assisted intensification of enzyme activity and its properties: a mini-review.

Science.gov (United States)

Nadar, Shamraja S; Rathod, Virendra K

2017-08-22

Over the last decade, ultrasound technique has emerged as the potential technology which shows large applications in food and biotechnology processes. Earlier, ultrasound has been employed as a method of enzyme inactivation but recently, it has been found that ultrasound does not inactivate all enzymes, particularly, under mild conditions. It has been shown that the use of ultrasonic treatment at appropriate frequencies and intensity levels can lead to enhanced enzyme activity due to favourable conformational changes in protein molecules without altering its structural integrity. The present review article gives an overview of influence of ultrasound irradiation parameters (intensity, duty cycle and frequency) and enzyme related factors (enzyme concentration, temperature and pH) on the catalytic activity of enzyme during ultrasound treatment. Also, it includes the effect of ultrasound on thermal kinetic parameters and Michaelis-Menten kinetic parameters (k m and V max ) of enzymes. Further, in this review, the physical and chemical effects of ultrasound on enzyme have been correlated with thermodynamic parameters (enthalpy and entropy). Various techniques used for investigating the conformation changes in enzyme after sonication have been highlighted. At the end, different techniques of immobilization for ultrasound treated enzyme have been summarized.

SCREENING OF THERMOPHYLIC MICROORGANISM FROM IJEN CRATER BANYUWANGI AS PHYTASE ENZYME PRODUCER

OpenAIRE

Kusumadjaja, Aline Puspita; Budiati, Tutuk; Puspaningsih, Ni Nyoman Tri; Sajidan, Sajidan

2010-01-01

Phytase is enzyme which hydrolysis phytic acid to anorganic phosphate and myo-inositol pentakis-, tetrakis-, tris-, bis-, and monophosphate. The use of phytase in feed industry can overcome environment and nutrition problems which were arisen from unmetabolism phytic acid or its salt by poultry, swine and fish. The feed industry needs a thermostable enzyme due to the need of high temperature in pelleting process, i.e. 81 °C. By using thermostabile phytase, the pelleting process will not affec...

Effect of Additives on the Selectivity and Reactivity of Enzymes.

Science.gov (United States)

Liang, Yi-Ru; Wu, Qi; Lin, Xian-Fu

2017-01-01

Enzymes have been widely used as efficient, eco-friendly, and biodegradable catalysts in organic chemistry due to their mild reaction conditions and high selectivity and efficiency. In recent years, the catalytic promiscuity of many enzymes in unnatural reactions has been revealed and studied by chemists and biochemists, which has expanded the application potential of enzymes. To enhance the selectivity and activity of enzymes in their natural or promiscuous reactions, many methods have been recommended, such as protein engineering, process engineering, and media engineering. Among them, the additive approach is very attractive because of its simplicity to use and high efficiency. In this paper, we will review the recent developments about the applications of additives to improve the catalytic performances of enzymes in their natural and promiscuous reactions. These additives include water, organic bases, water mimics, cosolvents, crown ethers, salts, surfactants, and some particular molecular additives. © 2017 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Vitamin D and Its Analogues Decrease Amyloid-β (Aβ) Formation and Increase Aβ-Degradation.

Science.gov (United States)

Grimm, Marcus O W; Thiel, Andrea; Lauer, Anna A; Winkler, Jakob; Lehmann, Johannes; Regner, Liesa; Nelke, Christopher; Janitschke, Daniel; Benoist, Céline; Streidenberger, Olga; Stötzel, Hannah; Endres, Kristina; Herr, Christian; Beisswenger, Christoph; Grimm, Heike S; Bals, Robert; Lammert, Frank; Hartmann, Tobias

2017-12-19

Alzheimer's disease (AD) is characterized by extracellular plaques in the brain, mainly consisting of amyloid-β (Aβ), as derived from sequential cleavage of the amyloid precursor protein. Epidemiological studies suggest a tight link between hypovitaminosis of the secosteroid vitamin D and AD. Besides decreased vitamin D level in AD patients, an effect of vitamin D on Aβ-homeostasis is discussed. However, the exact underlying mechanisms remain to be elucidated and nothing is known about the potential effect of vitamin D analogues. Here we systematically investigate the effect of vitamin D and therapeutically used analogues (maxacalcitol, calcipotriol, alfacalcidol, paricalcitol, doxercalciferol) on AD-relevant mechanisms. D₂ and D₃ analogues decreased Aβ-production and increased Aβ-degradation in neuroblastoma cells or vitamin D deficient mouse brains. Effects were mediated by affecting the Aβ-producing enzymes BACE1 and γ-secretase. A reduced secretase activity was accompanied by a decreased BACE1 protein level and nicastrin expression, an essential component of the γ-secretase. Vitamin D and analogues decreased β-secretase activity, not only in mouse brains with mild vitamin D hypovitaminosis, but also in non-deficient mouse brains. Our results further strengthen the link between AD and vitamin D, suggesting that supplementation of vitamin D or vitamin D analogues might have beneficial effects in AD prevention.

The surface science of enzymes

DEFF Research Database (Denmark)

Rod, Thomas Holm; Nørskov, Jens Kehlet

2002-01-01

One of the largest challenges to science in the coming years is to find the relation between enzyme structure and function. Can we predict which reactions an enzyme catalyzes from knowledge of its structure-or from its amino acid sequence? Can we use that knowledge to modify enzyme function......? To solve these problems we must understand in some detail how enzymes interact with reactants from its surroundings. These interactions take place at the surface of the enzyme and the question of enzyme function can be viewed as the surface science of enzymes. In this article we discuss how to describe...... catalysis by enzymes, and in particular the analogies between enzyme catalyzed reactions and surface catalyzed reactions. We do this by discussing two concrete examples of reactions catalyzed both in nature (by enzymes) and in industrial reactors (by inorganic materials), and show that although analogies...

Seaweed hydrocolloid production: an update on enzyme assisted extraction and modification technologies.

Science.gov (United States)

Rhein-Knudsen, Nanna; Ale, Marcel Tutor; Meyer, Anne S

2015-05-27

Agar, alginate, and carrageenans are high-value seaweed hydrocolloids, which are used as gelation and thickening agents in different food, pharmaceutical, and biotechnological applications. The annual global production of these hydrocolloids has recently reached 100,000 tons with a gross market value just above US$ 1.1 billion. The techno-functional properties of the seaweed polysaccharides depend strictly on their unique structural make-up, notably degree and position of sulfation and presence of anhydro-bridges. Classical extraction techniques include hot alkali treatments, but recent research has shown promising results with enzymes. Current methods mainly involve use of commercially available enzyme mixtures developed for terrestrial plant material processing. Application of seaweed polysaccharide targeted enzymes allows for selective extraction at mild conditions as well as tailor-made modifications of the hydrocolloids to obtain specific functionalities. This review provides an update of the detailed structural features of κ-, ι-, λ-carrageenans, agars, and alginate, and a thorough discussion of enzyme assisted extraction and processing techniques for these hydrocolloids.

Microbial-processing of fruit and vegetable wastes for production of vital enzymes and organic acids: Biotechnology and scopes.

Science.gov (United States)

Panda, Sandeep K; Mishra, Swati S; Kayitesi, Eugenie; Ray, Ramesh C

2016-04-01

Wastes generated from fruits and vegetables are organic in nature and contribute a major share in soil and water pollution. Also, green house gas emission caused by fruit and vegetable wastes (FVWs) is a matter of serious environmental concern. This review addresses the developments over the last one decade on microbial processing technologies for production of enzymes and organic acids from FVWs. The advances in genetic engineering for improvement of microbial strains in order to enhance the production of the value added bio-products as well as the concept of zero-waste economy have been briefly discussed. Copyright © 2015 Elsevier Inc. All rights reserved.

Magnetically responsive enzyme powders

Energy Technology Data Exchange (ETDEWEB)

Pospiskova, Kristyna, E-mail: kristyna.pospiskova@upol.cz [Regional Centre of Advanced Technologies and Materials, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Safarik, Ivo, E-mail: ivosaf@yahoo.com [Regional Centre of Advanced Technologies and Materials, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Department of Nanobiotechnology, Institute of Nanobiology and Structural Biology of GCRC, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic)

2015-04-15

Powdered enzymes were transformed into their insoluble magnetic derivatives retaining their catalytic activity. Enzyme powders (e.g., trypsin and lipase) were suspended in various liquid media not allowing their solubilization (e.g., saturated ammonium sulfate and highly concentrated polyethylene glycol solutions, ethanol, methanol, 2-propanol) and subsequently cross-linked with glutaraldehyde. Magnetic modification was successfully performed at low temperature in a freezer (−20 °C) using magnetic iron oxides nano- and microparticles prepared by microwave-assisted synthesis from ferrous sulfate. Magnetized cross-linked enzyme powders were stable at least for two months in water suspension without leakage of fixed magnetic particles. Operational stability of magnetically responsive enzymes during eight repeated reaction cycles was generally without loss of enzyme activity. Separation of magnetically modified cross-linked powdered enzymes from reaction mixtures was significantly simplified due to their magnetic properties. - Highlights: • Cross-linked enzyme powders were prepared in various liquid media. • Insoluble enzymes were magnetized using iron oxides particles. • Magnetic iron oxides particles were prepared by microwave-assisted synthesis. • Magnetic modification was performed under low (freezing) temperature. • Cross-linked powdered trypsin and lipase can be used repeatedly for reaction.

Arabinogalactan proteins: focus on carbohydrate active enzymes

Directory of Open Access Journals (Sweden)

Eva eKnoch

2014-06-01

Full Text Available Arabinogalactan proteins (AGPs are a highly diverse class of cell surface proteoglycans that are commonly found in most plant species. AGPs play important roles in many cellular processes during plant development, such as reproduction, cell proliferation, pattern formation and growth, and in plant-microbe interaction. However, little is known about the molecular mechanisms of their function. Numerous studies using monoclonal antibodies that recognize different AGP glycan epitopes have shown the appearance of a slightly altered AGP glycan in a specific stage of development in plant cells. Therefore, it is anticipated that the biosynthesis and degradation of AGP glycan is tightly regulated during development. Until recently, however, little was known about the enzymes involved in the metabolism of AGP glycans. In this review, we summarize recent discoveries of carbohydrate active enzymes (CAZy; http://www.cazy.org/ involved in the biosynthesis and degradation of AGP glycans, and we discuss the biological role of these enzymes in plant development.

Enzyme Histochemistry for Functional Histology in Invertebrates.

Science.gov (United States)

Cima, Francesca

2017-01-01

In invertebrates, enzyme histochemistry has recently found a renaissance regarding its applications in morphology and ecology. Many enzyme activities are useful for the morphofunctional characterization of cells, as biomarkers of biological and pathologic processes, and as markers of the response to environmental stressors. Here, the adjustments to classic techniques, including the most common enzymes used for digestion, absorption, transport, and oxidation, as well as techniques for azo-coupling, metal salt substitution and oxidative coupling polymerization, are presented in detail for various terrestrial and aquatic invertebrates. This chapter also provides strategies to solve the problems regarding anesthesia, small body size, the presence of an exo- or endoskeleton and the search for the best fixative in relation to the internal fluid osmolarity. These techniques have the aim of obtaining good results for both the pre- and post-embedding labeling of specimens, tissue blocks, sections, and hemolymph smears using both light and transmission electron microscopy.

Radiation and enzyme degradation of cellulose materials

International Nuclear Information System (INIS)

Duchacek, V.

1983-01-01

The results are summed up of a study of the effect of gamma radiation on pure cellulose and on wheat straw. The irradiation of cellulose yields acid substances - formic acid and polyhydroxy acids, toxic malondialdehyde and the most substantial fraction - the saccharides xylose, arabinose, glucose and certain oligosaccharides. A ten-fold reduction of the level of cellulose polymerization can be caused by relatively small doses - (up to 250 kGy). A qualitative analysis was made of the straw before and after irradiation and it was shown that irradiation had no significant effect on the qualitative composition of the straw. A 48 hour enzyme hydrolysis of the cellulose and straw were made after irradiation and an economic evaluation of the process was made. Radiation pretreatment is technically and economically advantageous; the production of fodder using enzyme hydrolysis of irradiated straw is not economically feasible due to the high cost of the enzyme. (M.D.)

The Brazilian Back Complaints in the Elders (Brazilian BACE) study: characteristics of Brazilian older adults with a new episode of low back pain.

Science.gov (United States)

Jesus-Moraleida, Fabianna Resende De; Ferreira, Paulo Henrique; Ferreira, Manuela Loureiro; Silva, Juscelio Pereira Da; Assis, Marcella Guimarães; Pereira, Leani Souza Máximo

Low back pain (LBP) is little explored in the aging population especially when considering age-relevant and culturally dependent outcomes. We aimed to describe socio-demographic and clinical characteristics of Brazilian older people with a new episode of LBP presenting to primary care. We sourced baseline information on socio-demographic, pain-related and clinical characteristics from 602 older adults from the Brazilian Back Complaints in the Elders (Brazilian BACE) study. We analyzed differences in pain, disability, functional capacity and psychosocial factors between sub-groups based on age (i.e. participants aged 55-74 or ≥75 years), education (i.e. those with four years or less of schooling or those with more than four years of schooling) and income (i.e. participants who reported earning two or less minimal wages or three and more). Participants presented severe LBP (7.18/10, SD: 2.59). Younger participants were slightly more disabled (mean difference 1.29 points, 95% confidence interval [CI]: 0.03/5.56), reporting poorer physical health, and less fall-related self-efficacy (mean difference of 2.41, 95% CI 0.35/4.46). Those less educated, and those with income equal or less than two minimum wages had more disability, pain catastrophizing and worse functional capacity. This was the first study showing that Brazilian older adults with LBP present high levels of functional disability and psychological distress, especially those with low socioeconomic status. Copyright © 2017 Associação Brasileira de Pesquisa e Pós-Graduação em Fisioterapia. Publicado por Elsevier Editora Ltda. All rights reserved.

A new generation of versatile chromogenic substrates for high-throughput analysis of biomass-degrading enzymes

DEFF Research Database (Denmark)

Kracun, Stjepan Kresimir; Schückel, Julia; Westereng, Bjørge

2015-01-01

of carbohydrate-acting enzymes to be putatively identified. However, there is a paucity of methods for rapidly screening the biochemical activities of these enzymes, and this is a serious bottleneck in the development of enzyme-reliant bio-refining processes. Results: We have developed a new generation of multi...

Kinetic characteristics of polygalacturonase enzymes hydrolyzing galacturonic acid oligomers using isothermal titration calorimetry

Science.gov (United States)

Polygalacturonase enzymes hydrolyze the polygalacturonic acid chains found in pectin. Interest in polygalacturonase enzymes continues as they are useful in a number of industrial processes and conversely, detrimental, as they are involved in maceration of economically important crops. While a good...

Thermodynamic activity-based intrinsic enzyme kinetic sheds light on enzyme-solvent interactions.

Science.gov (United States)

Grosch, Jan-Hendrik; Wagner, David; Nistelkas, Vasilios; Spieß, Antje C

2017-01-01

The reaction medium has major impact on biocatalytic reaction systems and on their economic significance. To allow for tailored medium engineering, thermodynamic phenomena, intrinsic enzyme kinetics, and enzyme-solvent interactions have to be discriminated. To this end, enzyme reaction kinetic modeling was coupled with thermodynamic calculations based on investigations of the alcohol dehydrogenase from Lactobacillus brevis (LbADH) in monophasic water/methyl tert-butyl ether (MTBE) mixtures as a model solvent. Substrate concentrations and substrate thermodynamic activities were varied separately to identify the individual thermodynamic and kinetic effects on the enzyme activity. Microkinetic parameters based on concentration and thermodynamic activity were derived to successfully identify a positive effect of MTBE on the availability of the substrate to the enzyme, but a negative effect on the enzyme performance. In conclusion, thermodynamic activity-based kinetic modeling might be a suitable tool to initially curtail the type of enzyme-solvent interactions and thus, a powerful first step to potentially understand the phenomena that occur in nonconventional media in more detail. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:96-103, 2017. © 2016 American Institute of Chemical Engineers.

Profiling the orphan enzymes

Science.gov (United States)

2014-01-01

The emergence of Next Generation Sequencing generates an incredible amount of sequence and great potential for new enzyme discovery. Despite this huge amount of data and the profusion of bioinformatic methods for function prediction, a large part of known enzyme activities is still lacking an associated protein sequence. These particular activities are called “orphan enzymes”. The present review proposes an update of previous surveys on orphan enzymes by mining the current content of public databases. While the percentage of orphan enzyme activities has decreased from 38% to 22% in ten years, there are still more than 1,000 orphans among the 5,000 entries of the Enzyme Commission (EC) classification. Taking into account all the reactions present in metabolic databases, this proportion dramatically increases to reach nearly 50% of orphans and many of them are not associated to a known pathway. We extended our survey to “local orphan enzymes” that are activities which have no representative sequence in a given clade, but have at least one in organisms belonging to other clades. We observe an important bias in Archaea and find that in general more than 30% of the EC activities have incomplete sequence information in at least one superkingdom. To estimate if candidate proteins for local orphans could be retrieved by homology search, we applied a simple strategy based on the PRIAM software and noticed that candidates may be proposed for an important fraction of local orphan enzymes. Finally, by studying relation between protein domains and catalyzed activities, it appears that newly discovered enzymes are mostly associated with already known enzyme domains. Thus, the exploration of the promiscuity and the multifunctional aspect of known enzyme families may solve part of the orphan enzyme issue. We conclude this review with a presentation of recent initiatives in finding proteins for orphan enzymes and in extending the enzyme world by the discovery of new

The complexities of hydrolytic enzymes from the termite digestive system.

Science.gov (United States)

Saadeddin, Anas

2014-06-01

The main challenge in second generation bioethanol production is the efficient breakdown of cellulose to sugar monomers (hydrolysis). Due to the recalcitrant character of cellulose, feedstock pretreatment and adapted hydrolysis steps are needed to obtain fermentable sugar monomers. The conventional industrial production process of second-generation bioethanol from biomass comprises several steps: thermochemical pretreatment, enzymatic hydrolysis and sugar fermentation. This process is undergoing continuous optimization in order to increase the bioethanol yield and reduce the economic cost. Therefore, the discovery of new enzymes with high lignocellulytic activity or new strategies is extremely important. In nature, wood-feeding termites have developed a sophisticated and efficient cellulose degrading system in terms of the rate and extent of cellulose hydrolysis and exploitation. This system, which represents a model for digestive symbiosis has attracted the attention of biofuel researchers. This review describes the termite digestive system, gut symbionts, termite enzyme resources, in vitro studies of isolated enzymes and lignin degradation in termites.

Reduction of β-amyloid accumulation by reticulon 3 in transgenic mice.

Science.gov (United States)

Araki, Wataru; Oda, Akiko; Motoki, Kazumi; Hattori, Kotaro; Itoh, Masayuki; Yuasa, Shigeki; Konishi, Yoshihiro; Shin, Ryong-Woon; Tamaoka, Akira; Ogino, Koichi

2013-02-01

Inhibition of the β-secretase, BACE1, which cleaves amyloid precursor protein (APP) to produce β-amyloid protein (Aβ), is thought to be a feasible therapeutic strategy for Alzheimer's disease. Reticulon (RTN) proteins such as RTN3 have been identified as membrane proteins that interact with BACE1 and inhibit its Aβ-generating activity. In this study, we investigated whether RTN3 can regulate Aβ production in vivo, using transgenic (Tg) mice expressing APP with Swedish and London mutations (APP Tg mice) and those expressing RTN3; the latter mice showed ~1.4-fold higher expression levels of RTN3 protein in the cerebral cortex than non-Tg controls. We analyzed the brains of single APP Tg and double APP/RTN3 Tg mice at the age of approximately 15 months. The levels of secreted APP-β, a direct BACE1 cleavage product of APP, in Tris-soluble fraction were considerably reduced in the hippocampus and cerebral cortex of APP/RTN3 Tg mice relative to those in APP Tg mice. Immunohistochemical analyses demonstrated that Aβ burden and plaques were significantly (by approximately 50%) decreased in both the hippocampus and cerebral cortex of double Tg mice compared to APP Tg mice. Furthermore, the levels of guanidine-soluble Aβ40 and Aβ42 in these brain regions of APP/RTN3 Tg mice were relatively lower than those in APP Tg mice. These findings indicate that even a small increase in RTN3 expression exerts suppressive effects on amyloidogenic processing of APP and Aβ accumulation through modulation of BACE1 activity in vivo, and suggest that induction of RTN3 might be an effective therapeutic strategy against Alzheimer's disease.

Effect of irradiation on immobilized enzymes compared with that on enzymes in solution

International Nuclear Information System (INIS)

Schachinger, L.; Schippel, C.; Altmann, E.; Diepold, B.; Yang, C.; Jaenike, M.; Hochhaeuser, E.

1985-01-01

Glucose oxidase and catalase were immobilized by attaching them to nylon fibers that had been treated with triethyloxonium-tetrafluoroborate, diaminohexane and glutaraldialdehyde according to Morris, Campell and Hornby (1975). This method assures that the enzymes are bound to a side chain of the polyamide structure. Enzyme activity (as measured by the O 2 -uptake and by microcalorimetry) was found to be unchanged after 2 years. The apparent Ksub(m)-constants of the immobilized enzymes with glucose were the same as those for enzymes in solution. GOD and catalase immobilized in poly(acrylamide) gel had the same Ksub(m)-value. Despite the high stability during storage, the radiation induced inactivation of enzymes immobilized on gel or chromosorb, an inorganic carrier, was of the same order of magnitude as that of the dissolved enzymes. The enzymes bound to nylon fibers showed a higher radiation sensitivity. This might have been caused by an additional attack on the binding site of the carrier. (orig.)

Direct Electron Transfer of Enzymes in a Biologically Assembled Conductive Nanomesh Enzyme Platform.

Science.gov (United States)

Lee, Seung-Woo; Lee, Ki-Young; Song, Yong-Won; Choi, Won Kook; Chang, Joonyeon; Yi, Hyunjung

2016-02-24

Nondestructive assembly of a nanostructured enzyme platform is developed in combination of the specific biomolecular attraction and electrostatic coupling for highly efficient direct electron transfer (DET) of enzymes with unprecedented applicability and versatility. The biologically assembled conductive nanomesh enzyme platform enables DET-based flexible integrated biosensors and DET of eight different enzyme with various catalytic activities. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Processing of Nonconjugative Resistance Plasmids by Conjugation Nicking Enzyme of Staphylococci

Energy Technology Data Exchange (ETDEWEB)

Pollet, Rebecca M.; Ingle, James D.; Hymes, Jeff P.; Eakes, Thomas C.; Eto, Karina Yui; Kwong, Stephen M.; Ramsay, Joshua P.; Firth, Neville; Redinbo, Matthew R. (Curtin U.); (Sydney); (UNC)

2016-01-04

mechanism of antimicrobial resistance transfer in bacteria such asStaphylococcus aureusis an important step toward potentially slowing the spread of antimicrobial-resistant infections. This work establishes protein-DNA interactions essential for the transfer of theStaphylococcus aureusmultiresistance plasmid pSK41 by its relaxase, NES. This enzyme also processed variantoriT-like sequences found on numerous plasmids previously considered nontransmissible, suggesting that in conjunction with an uncharacterized accessory protein, these plasmids may be transferred horizontally via a relaxase intransmechanism. These findings have important implications for our understanding of staphylococcal resistance plasmid evolution.

[Treatment of burn surfaces by proteinases: mathematical description of an enzyme distribution].

Science.gov (United States)

Khalili, A S; Domogatskiĭ, S P; Blizniukov, O P; Ruuge, E K

2003-01-01

The process of penetration of a proteolytic enzyme applied to the surface of burn wound into the depth of necrotic tissue was considered. The model approximation describes three factors by a series of mathematical equations: inward-directed enzyme diffusion, counter-flow filtration of interstitial fluid (exudates), and irreversible inactivation of the enzyme by specific inhibitors present in exudates. According to the model, a quasi-stationary distribution of enzymatic activity through the thickness of the necrotic layer is achieved within 3 h and persists as long as the enzyme concentration on the wound surface is constant. The enzyme activity diminishes linearly from the wound surface to the mid-part of the necrotic layer. No enzyme activity is retained in the inner mid-part of the necrotic layer completely protected by the prevalent inhibitor. The ratio of enzyme concentration on the wound surface to inhibitor concentration in the interstitial fluid is the same as the ratio of the depth of active enzyme area to the depth of the inhibitor-protected area through the necrotic layer. The dynamics of accumulation of the active enzyme in the necrotic zone and the rate of enzyme inactivation in the wound by inhibitors were described by formulas applicable for practical purposes.

On the Structural Context and Identification of Enzyme Catalytic Residues

Directory of Open Access Journals (Sweden)

Yu-Tung Chien

2013-01-01

Full Text Available Enzymes play important roles in most of the biological processes. Although only a small fraction of residues are directly involved in catalytic reactions, these catalytic residues are the most crucial parts in enzymes. The study of the fundamental and unique features of catalytic residues benefits the understanding of enzyme functions and catalytic mechanisms. In this work, we analyze the structural context of catalytic residues based on theoretical and experimental structure flexibility. The results show that catalytic residues have distinct structural features and context. Their neighboring residues, whether sequence or structure neighbors within specific range, are usually structurally more rigid than those of noncatalytic residues. The structural context feature is combined with support vector machine to identify catalytic residues from enzyme structure. The prediction results are better or comparable to those of recent structure-based prediction methods.

Production of Enzymes From Agricultural Wastes and Their Potential Industrial Applications.

Science.gov (United States)

Bharathiraja, S; Suriya, J; Krishnan, M; Manivasagan, P; Kim, S-K

Enzymatic hydrolysis is the significant technique for the conversion of agricultural wastes into valuable products. Agroindustrial wastes such as rice bran, wheat bran, wheat straw, sugarcane bagasse, and corncob are cheapest and plentifully available natural carbon sources for the production of industrially important enzymes. Innumerable enzymes that have numerous applications in industrial processes for food, drug, textile, and dye use have been produced from different types of microorganisms from agricultural wastes. Utilization of agricultural wastes offers great potential for reducing the production cost and increasing the use of enzymes for industrial purposes. This chapter focuses on economic production of actinobacterial enzymes from agricultural wastes to make a better alternative for utilization of biomass generated in million tons as waste annually. © 2017 Elsevier Inc. All rights reserved.

A Kinetic Modelling of Enzyme Inhibitions in the Central Metabolism of Yeast Cells

Science.gov (United States)

Kasbawati; Kalondeng, A.; Aris, N.; Erawaty, N.; Azis, M. I.

2018-03-01

Metabolic regulation plays an important role in the metabolic engineering of a cellular process. It is conducted to improve the productivity of a microbial process by identifying the important regulatory nodes of a metabolic pathway such as fermentation pathway. Regulation of enzymes involved in a particular pathway can be held to improve the productivity of the system. In the central metabolism of yeast cell, some enzymes are known as regulating enzymes that can be inhibited to increase the production of ethanol. In this research we study the kinetic modelling of the enzymes in the central pathway of yeast metabolism by taking into consideration the enzyme inhibition effects to the ethanol production. The existence of positive steady state solution and the stability of the system are also analysed to study the property and dynamical behaviour of the system. One stable steady state of the system is produced if some conditions are fulfilled. The conditions concern to the restriction of the maximum reactions of the enzymes in the pyruvate and acetaldehyde branch points. There exists a certain time of fermentation reaction at which a maximum and a minimum ethanol productions are attained after regulating the system. Optimal ethanol concentration is also produced for a certain initial concentration of inhibitor.

Enzymes for improved biomass conversion

Science.gov (United States)

Brunecky, Roman; Himmel, Michael E.

2016-02-02

Disclosed herein are enzymes and combinations of the enzymes useful for the hydrolysis of cellulose and the conversion of biomass. Methods of degrading cellulose and biomass using enzymes and cocktails of enzymes are also disclosed.

Enhancing the functional properties of thermophilic enzymes by chemical modification and immobilization.

Science.gov (United States)

Cowan, Don A; Fernandez-Lafuente, Roberto

2011-09-10

The immobilization of proteins (mostly typically enzymes) onto solid supports is mature technology and has been used successfully to enhance biocatalytic processes in a wide range of industrial applications. However, continued developments in immobilization technology have led to more sophisticated and specialized applications of the process. A combination of targeted chemistries, for both the support and the protein, sometimes in combination with additional chemical and/or genetic engineering, has led to the development of methods for the modification of protein functional properties, for enhancing protein stability and for the recovery of specific proteins from complex mixtures. In particular, the development of effective methods for immobilizing large multi-subunit proteins with multiple covalent linkages (multi-point immobilization) has been effective in stabilizing proteins where subunit dissociation is the initial step in enzyme inactivation. In some instances, multiple benefits are achievable in a single process. Here we comprehensively review the literature pertaining to immobilization and chemical modification of different enzyme classes from thermophiles, with emphasis on the chemistries involved and their implications for modification of the enzyme functional properties. We also highlight the potential for synergies in the combined use of immobilization and other chemical modifications. Copyright © 2011 Elsevier Inc. All rights reserved.

Use of a proteolytic enzyme in cocoa (Theobroma cacao L.) processing

OpenAIRE

Brito,Edy Sousa de; Pezoa García,Nelson Horacio; Amancio,Allan César

2004-01-01

Protein hydrolysis using an exogenous protease on cocoa nibs was performed to verify the formation of precursors and the effect on cocoa flavour. An experimental design was used to check the influence of temperature (30 to 70 ºC) and enzyme : substrate ratio [E/S] (97.5 to 1267.5 U g-1 of protein). The % Degree of Hydrolysis (% DH) was affected mainly by [E/S] leading to a 4-fold increase (from 5 to 20 %) after 6 hours of treatment. During cocoa nibs roasting, there was a greater consumption ...

Effect of enzyme supplements on macronutrient digestibility by healthy adult dogs.

Science.gov (United States)

Villaverde, Cecilia; Manzanilla, Edgar G; Molina, Jenifer; Larsen, Jennifer A

2017-01-01

Some enzyme supplement products claim benefits for healthy dogs to compensate for alleged suboptimal production of endogenous enzymes and the loss of enzymes in commercial pet foods secondary to processing. The objective of the current study was to determine macronutrient and energy digestibility by healthy adult dogs fed a commercial maintenance diet with or without supplementation with plant- and animal-origin enzyme products at the dosage recommended by their respective manufacturers. A group of fourteen healthy neutered adult Beagle dogs (average age 8 years) was divided into two equal groups and fed the basal diet alone and then with either the plant- or animal-origin enzyme supplement in three consecutive 10-d periods; the treatment groups received the opposite enzyme supplement in the third period. Digestibility in each period was performed by the total faecal collection method. Serum trypsin-like immunoreactivity (TLI) was measured at the end of each trial. Data were analysed by repeated measures and the α level of significance was set at 0·05. There were no differences in energy and nutrient digestibility between enzyme treatments. When comparing basal with enzyme supplementation, fat digestibility was higher for the basal diet compared with the animal-origin enzyme treatment, which could be a period effect and was not biologically significant (94·7 v . 93·5 %). Serum TLI was not affected by supplementation with either enzyme product. Exogenous enzyme supplementation did not significantly increase digestibility of a typical commercial dry diet in healthy adult dogs and routine use of such products is not recommended.

Immobilised enzymes in biorenewable production

OpenAIRE

Franssen, M.C.R.; Steunenberg, P.; Scott, E.L.; Zuilhof, H.; Sanders, J.P.M.

2013-01-01

Oils, fats, carbohydrates, lignin, and amino acids are all important raw materials for the production of biorenewables. These compounds already play an important role in everyday life in the form of wood, fabrics, starch, paper and rubber. Enzymatic reactions do, in principle, allow the transformation of these raw materials into biorenewables under mild and sustainable conditions. There are a few examples of processes using immobilised enzymes that are already applied on an industrial scale, ...

Halophilic Bacteria as a Source of Novel Hydrolytic Enzymes

Science.gov (United States)

de Lourdes Moreno, María; Pérez, Dolores; García, María Teresa; Mellado, Encarnación

2013-01-01

Hydrolases constitute a class of enzymes widely distributed in nature from bacteria to higher eukaryotes. The halotolerance of many enzymes derived from halophilic bacteria can be exploited wherever enzymatic transformations are required to function under physical and chemical conditions, such as in the presence of organic solvents and extremes in temperature and salt content. In recent years, different screening programs have been performed in saline habitats in order to isolate and characterize novel enzymatic activities with different properties to those of conventional enzymes. Several halophilic hydrolases have been described, including amylases, lipases and proteases, and then used for biotechnological applications. Moreover, the discovery of biopolymer-degrading enzymes offers a new solution for the treatment of oilfield waste, where high temperature and salinity are typically found, while providing valuable information about heterotrophic processes in saline environments. In this work, we describe the results obtained in different screening programs specially focused on the diversity of halophiles showing hydrolytic activities in saline and hypersaline habitats, including the description of enzymes with special biochemical properties. The intracellular lipolytic enzyme LipBL, produced by the moderately halophilic bacterium Marinobacter lipolyticus, showed advantages over other lipases, being an enzyme active over a wide range of pH values and temperatures. The immobilized LipBL derivatives obtained and tested in regio- and enantioselective reactions, showed an excellent behavior in the production of free polyunsaturated fatty acids (PUFAs). On the other hand, the extremely halophilic bacterium, Salicola marasensis sp. IC10 showing lipase and protease activities, was studied for its ability to produce promising enzymes in terms of its resistance to temperature and salinity. PMID:25371331

Halophilic Bacteria as a Source of Novel Hydrolytic Enzymes

Directory of Open Access Journals (Sweden)

Encarnación Mellado

2013-01-01

Full Text Available Hydrolases constitute a class of enzymes widely distributed in nature from bacteria to higher eukaryotes. The halotolerance of many enzymes derived from halophilic bacteria can be exploited wherever enzymatic transformations are required to function under physical and chemical conditions, such as in the presence of organic solvents and extremes in temperature and salt content. In recent years, different screening programs have been performed in saline habitats in order to isolate and characterize novel enzymatic activities with different properties to those of conventional enzymes. Several halophilic hydrolases have been described, including amylases, lipases and proteases, and then used for biotechnological applications. Moreover, the discovery of biopolymer-degrading enzymes offers a new solution for the treatment of oilfield waste, where high temperature and salinity are typically found, while providing valuable information about heterotrophic processes in saline environments. In this work, we describe the results obtained in different screening programs specially focused on the diversity of halophiles showing hydrolytic activities in saline and hypersaline habitats, including the description of enzymes with special biochemical properties. The intracellular lipolytic enzyme LipBL, produced by the moderately halophilic bacterium Marinobacter lipolyticus, showed advantages over other lipases, being an enzyme active over a wide range of pH values and temperatures. The immobilized LipBL derivatives obtained and tested in regio- and enantioselective reactions, showed an excellent behavior in the production of free polyunsaturated fatty acids (PUFAs. On the other hand, the extremely halophilic bacterium, Salicola marasensis sp. IC10 showing lipase and protease activities, was studied for its ability to produce promising enzymes in terms of its resistance to temperature and salinity.

Enzyme inhibition by iminosugars

DEFF Research Database (Denmark)

López, Óscar; Qing, Feng-Ling; Pedersen, Christian Marcus

2013-01-01

Imino- and azasugar glycosidase inhibitors display pH dependant inhibition reflecting that both the inhibitor and the enzyme active site have groups that change protonation state with pH. With the enzyme having two acidic groups and the inhibitor one basic group, enzyme-inhibitor complexes...

Targeted enzyme prodrug therapies.

Science.gov (United States)

Schellmann, N; Deckert, P M; Bachran, D; Fuchs, H; Bachran, C

2010-09-01

The cure of cancer is still a formidable challenge in medical science. Long-known modalities including surgery, chemotherapy and radiotherapy are successful in a number of cases; however, invasive, metastasized and inaccessible tumors still pose an unresolved and ongoing problem. Targeted therapies designed to locate, detect and specifically kill tumor cells have been developed in the past three decades as an alternative to treat troublesome cancers. Most of these therapies are either based on antibody-dependent cellular cytotoxicity, targeted delivery of cytotoxic drugs or tumor site-specific activation of prodrugs. The latter is a two-step procedure. In the first step, a selected enzyme is accumulated in the tumor by guiding the enzyme or its gene to the neoplastic cells. In the second step, a harmless prodrug is applied and specifically converted by this enzyme into a cytotoxic drug only at the tumor site. A number of targeting systems, enzymes and prodrugs were investigated and improved since the concept was first envisioned in 1974. This review presents a concise overview on the history and latest developments in targeted therapies for cancer treatment. We cover the relevant technologies such as antibody-directed enzyme prodrug therapy (ADEPT), gene-directed enzyme prodrug therapy (GDEPT) as well as related therapies such as clostridial- (CDEPT) and polymer-directed enzyme prodrug therapy (PDEPT) with emphasis on prodrug-converting enzymes, prodrugs and drugs.

Biochemical characterization of enzyme fidelity of influenza A virus RNA polymerase complex.

Directory of Open Access Journals (Sweden)

Shilpa Aggarwal

2010-04-01

Full Text Available It is widely accepted that the highly error prone replication process of influenza A virus (IAV, together with viral genome assortment, facilitates the efficient evolutionary capacity of IAV. Therefore, it has been logically assumed that the enzyme responsible for viral RNA replication process, influenza virus type A RNA polymerase (IAV Pol, is a highly error-prone polymerase which provides the genomic mutations necessary for viral evolution and host adaptation. Importantly, however, the actual enzyme fidelity of IAV RNA polymerase has never been characterized.Here we established new biochemical assay conditions that enabled us to assess both polymerase activity with physiological NTP pools and enzyme fidelity of IAV Pol. We report that IAV Pol displays highly active RNA-dependent RNA polymerase activity at unbiased physiological NTP substrate concentrations. With this robust enzyme activity, for the first time, we were able to compare the enzyme fidelity of IAV Pol complex with that of bacterial phage T7 RNA polymerase and the reverse transcriptases (RT of human immunodeficiency virus (HIV-1 and murine leukemia virus (MuLV, which are known to be low and high fidelity enzymes, respectively. We observed that IAV Pol displayed significantly higher fidelity than HIV-1 RT and T7 RNA polymerase and equivalent or higher fidelity than MuLV RT. In addition, the IAV Pol complex showed increased fidelity at lower temperatures. Moreover, upon replacement of Mg(++ with Mn(++, IAV Pol displayed increased polymerase activity, but with significantly reduced processivity, and misincorporation was slightly elevated in the presence of Mn(++. Finally, when the IAV nucleoprotein (NP was included in the reactions, the IAV Pol complex exhibited enhanced polymerase activity with increased fidelity.Our study indicates that IAV Pol is a high fidelity enzyme. We envision that the high fidelity nature of IAV Pol may be important to counter-balance the multiple rounds of

2008 GRC Iron Sulfur Enzymes-Conference to be held June 8-13, 2008

Energy Technology Data Exchange (ETDEWEB)

Cramer, Stephen [Univ. of California, Davis, CA (United States); Gray, Nancy Ryan [Gordon Research Conferences, West Kingston, RI (United States)

2009-01-01

Iron-sulfur proteins are among the most common and ancient enzymes and electron-transfer agents in nature. They play key roles in photosynthesis, respiration, and the metabolism of small molecules such as H2, CO, and N2. The Iron Sulfur Enzyme Gordon Research Conference evolved from an earlier GRC on Nitrogen Fixation that began in 1994. The scope of the current meeting has broadened to include all enzymes or metalloproteins in which Fe-S bonds play a key role. This year's meeting will focus on the biosynthesis of Fe-S clusters, as well as the structure and mechanism of key Fe-S enzymes such as hydrogenase, nitrogenase and its homologues, radical SAM enzymes, and aconitase-related enzymes. Recent progress on the role of Fe-S enzymes in health, disease, DNA/RNA-processing, and alternative bio-energy systems will also be highlighted. This conference will assemble a broad, diverse, and international group of biologists and chemists who are investigating fundamental issues related to Fe-S enzymes, on atomic, molecular, organism, and environmental scales. The topics to be addressed will include: Biosynthesis & Genomics of Fe-S Enzymes; Fundamental Fe-S Chemistry; Hydrogen and Fe-S Enzymes; Nitrogenase & Homologous Fe-S Enzymes; Fe-S Enzymes in Health & Disease; Radical SAM and Aconitase-Related Fe-S Enzymes; Fe-S Enzymes and Synthetic Analogues in BioEnergy; and Fe-S Enzymes in Geochemistry and the Origin of Life.

Actinomycete enzymes and activities involved in straw saccharification

Energy Technology Data Exchange (ETDEWEB)

McCarthy, A J; Ball, A S [Liverpool Univ. (UK). Dept. of Genetics and Microbiology

1990-01-01

This research programme has been directed towards the analysis of actinomycete enzyme systems involved in the degradation of plant biomass (lignocellulose.) The programme was innovative in that a novel source of enzymes was systematically screened and wheat straw saccharifying activity was the test criterion. Over 200 actinomycete strains representing a broad taxonomic range were screened. A range of specific enzyme activities were involved and included cellulase, xylanase, arabinofuranosidase, acetylesterase, {beta}-xylosidase and {beta}-glucosidase. Since hemicellulose (arabinoxylan) was the primary source of sugar, xylanases were characterized. The xylan-degrading systems of actinomycetes were complex and nonuniform, with up to six separate endoxylanases identified in active strains. Except for microbispora bispora, actinomycetes were found to be a poor source of cellulase activity. Evidence for activity against the lignin fraction of straw was produced for a range of actinomycete strains. While modification reactions were common, cleavage of inter-monomer bonds, and utilization of complex polyphenolic compounds were restricted to two strains: Thermomonospora mesophila and Streptomyces badius. Crude enzyme preparations from actinomycetes can be used to generate sugar, particularly pentoses, directly from cereal straw. The potential for improvements in yield rests with the formulation to cooperative enzyme combinations from different strains. The stability properties of enzymes from thermophilic strains and the general neutral to alkali pH optima offer advantages in certain process situations. Actinomycetes are a particularly rich source of xylanases for commercial application and can rapidly solubilise a lignocarbohydrate fraction of straw which may have both product and pretreatment potential. 31 refs., 4 figs., 5 tabs.

Determination of histamine in Iranian cheese using enzyme-linked ...

African Journals Online (AJOL)

john

enzyme-linked immunosorbent assay (ELISA) method. Mojtaba ... Histamine is a simple chemical substance created during processing of the amine acid histidine. Histamine is also an .... Institute of environment Health and Forensic. Sciences ...

Seaweed Hydrocolloid Production: An Update on Enzyme Assisted Extraction and Modification Technologies

Directory of Open Access Journals (Sweden)

Nanna Rhein-Knudsen

2015-05-01

Full Text Available Agar, alginate, and carrageenans are high-value seaweed hydrocolloids, which are used as gelation and thickening agents in different food, pharmaceutical, and biotechnological applications. The annual global production of these hydrocolloids has recently reached 100,000 tons with a gross market value just above US$ 1.1 billion. The techno-functional properties of the seaweed polysaccharides depend strictly on their unique structural make-up, notably degree and position of sulfation and presence of anhydro-bridges. Classical extraction techniques include hot alkali treatments, but recent research has shown promising results with enzymes. Current methods mainly involve use of commercially available enzyme mixtures developed for terrestrial plant material processing. Application of seaweed polysaccharide targeted enzymes allows for selective extraction at mild conditions as well as tailor-made modifications of the hydrocolloids to obtain specific functionalities. This review provides an update of the detailed structural features of κ-, ι-, λ-carrageenans, agars, and alginate, and a thorough discussion of enzyme assisted extraction and processing techniques for these hydrocolloids.

Effect of hemicellulolytic enzymes on mesophilic methane fermentation

Energy Technology Data Exchange (ETDEWEB)

Oi, S; Matsui, Y; Iizuka, M; Yamamoto, T

1977-01-01

Mesophilic methane fermentation was examined using soybean seed coat, a waste from soybean processing for oil manufacture, with or without treatment with hemicellulolytic enzymes of Aspergillus niger, and the following results were obtained: (1) The methane fermentation bacteria acclimated to soybean seed coat medium were shown to consume monosaccharides and evolve methane in the following decreasing order: glucose, fructose, mannose > xylose, galactose, glucosamine, galacturonic acid > arabinose. The bacteria were also shown to form methane from a gas mixture of hydrogen and carbon dioxide. (2) In fermentation of soybean seed coat treated with the fungal enzyme, about 70% of the total sugar content as consumed in four weeks, and the gas evolution was about twice that without the fungal enzyme. The gas evolved was composed of 60% methane and 36% carbon dioxide. In general, vigorous evolution of hydrogen and carbon dioxide occurred at a very early stage of fermentation, and was followed by formation of methane. The maximum gas evolution of the enzyme-treated mash took place in 6 days while that of untreated mash occurred one week later. Chemical oxygen demand of the supernatant of the former mash was decreased by fermentation to 7.0% of the initial level.

Identification of interleukin-8 converting enzyme as cathepsin L.

Science.gov (United States)

Ohashi, Kensaku; Naruto, Masanobu; Nakaki, Toshio; Sano, Emiko

2003-06-26

IL-8 is produced by various cells, and the NH(2)-terminal amino acid sequence of IL-8 displays heterogeneity among cell types. The mature form of IL-8 has 72 amino acids (72IL-8), while a precursor form (77IL-8) of IL-8 has five additional amino acids to the 72IL-8 NH(2)-terminal. However, it has been unclear how IL-8 is processed to yield the mature form. In this study, converting enzyme was purified as a single 31-kDa band on silver-stained polyacrylamide gel from 160 l of cultured fibroblast supernatant by sequential chromatography. NH(2)-terminal amino acid sequence analysis revealed a sequence, EAPRSVDWRE, which was identified as a partial sequence of cathepsin L. Polyclonal antibodies raised against cathepsin L recognized the purified converting enzyme on Western blot. Moreover, human hepatic cathepsin L cleaved 77IL-8 between Arg(5) and Ser(6), which is the same cleavage site as the putative converting enzyme, resulting in 72IL-8 formation. These data indicate that the converting enzyme of the partially purified fraction of the human fibroblast culture supernatant was cathepsin L. Furthermore, 72IL-8 was sevenfold more potent than 77IL-8 in a neutrophil chemotaxis assay. These results show that cathepsin L is secreted from human fibroblasts in response to external stimuli and plays an important role in IL-8 processing in inflammatory sites.

[Effect of melaxen on free radical processes intensity and some antioxidant enzymes activity in rats liver and blood serum under type 2 diabetes mellitus].

Science.gov (United States)

Verevkin, A N; Popova, T N; Agarkov, A A; Semenikhina, A V

2015-01-01

The effect of melaxen on free radical processes and activity of superoxide dismutase and catalase in rats with type 2 diabetes mellitus (T2DM) has been investigated. It was established that melaxen administration to diabetic rats caused a decrease of the intensity of free radical processes as evidenced a decrease of the lipid peroxidation primary products content and biochemiluminescence parameters. The activity of the antioxidant enzymes changed towards normal values. These effects were probably induced by the correction of the melatonin level at the result of the melaxen action.

Enzyme activities at different stages of plant biomass decomposition in three species of fungus-growing termites

DEFF Research Database (Denmark)

da Costa, Rafael R.; Hu, Haofu; Pilgaard, Bo

2018-01-01

contributing to the success of the termites as the main plant decomposers in the Old World. Here we evaluate which plant polymers are decomposed and which enzymes are active during the decomposition process in two major genera of fungus-growing termites. We find a diversity of active enzymes at different...... stages of decomposition and a consistent decrease in plant components during the decomposition process. Furthermore, our findings are consistent with the hypothesis that termites transport enzymes from the older mature parts of the fungus comb through young worker guts to freshly inoculated plant...... substrate. However, preliminary fungal RNAseq analyses suggest that this likely transport is supplemented with enzymes produced in situ Our findings support that the maintenance of an external fungus comb, inoculated with an optimal mix of plant material, fungal spores, and enzymes, is likely the key...