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Cofactor regeneration

Patrick Starlinger, David Pereyra, Stefanie Haegele, Paul Braeuer, Lukas Oehlberger, Florian Primavesi, Andreas Kohler, Florian Offensperger, Thomas Reiberger, Arnulf Ferlitsch, Barbara Messner, Guido Beldi, Stefan Staettner, Christine Brostjan, Thomas Gruenberger
Von Willebrand Factor (vWF) was found to mediate platelet influx during the early phase of liver regeneration in mice. Further, increased vWF-antigen (vWF-Ag) levels were shown to be predictive for outcome of patients with chronic liver disease. Accordingly, we aimed to assess the relevance of perioperative vWF-Ag dynamics in terms of liver regeneration and clinical outcome in patients undergoing liver resection (LR). Accordingly, we observed that vWF-Ag and its activity - estimated via ristocetin cofactor measurement - increased immediately after induction of liver regeneration and was associated with platelet accumulation within the liver...
November 15, 2017: Hepatology: Official Journal of the American Association for the Study of Liver Diseases
Thierry Léveillard, Najate Aït-Ali
Thioredoxins are small thiol-oxidoreductase enzymes that control cellular redox homeostasis. Paradoxically, human thioredoxin (TXN1) was first identified as the adult T cell leukemia-derived factor (ADF), a secreted protein. ADF has been implicated in a wide variety of cell-to-cell communication systems acting as a cytokine or a chemokine. TRX80 is a truncated TXN1 protein with cytokine activity. The unconventional secretion mechanism of these extracellular thioredoxins is unknown. The thioredoxin system is relying on glucose metabolism through the pentose phosphate pathway that provides reducing power in the form of NADPH, the cofactor of thioredoxin reductase (TXNRD)...
2017: Oxidative Medicine and Cellular Longevity
Lisa Marie Schmitz, Katrin Rosenthal, Stephan Lütz
Oxidoreductases are enzymes with a high potential for organic synthesis, as their selectivity often exceeds comparable chemical syntheses. The biochemical cofactors of these enzymes need regeneration during synthesis. Several regeneration methods are available but the electrochemical approach offers an efficient and quasi mass-free method for providing the required redox equivalents. Electron transfer systems involving direct regeneration of natural and artificial cofactors, indirect electrochemical regeneration via a mediator, and indirect electroenzymatic cofactor regeneration via enzyme and mediator have been investigated...
November 14, 2017: Advances in Biochemical Engineering/biotechnology
Jian-Wei Zhao, Hua-Lei Wu, Jian-Dong Zhang, Wen-Chao Gao, Xiao-Jun Fan, Hong-Hong Chang, Wen-Long Wei, Jian-He Xu
OBJECTIVES: To investigate the efficiency of a new cascade biocatalysis system for the conversion of R, S-β-amino alcohols to enantiopure vicinal diol and β-amino alcohol. RESULTS: An efficient cascade biocatalysis was achieved by combination of a transaminase, a carbonyl reductase and a cofactor regeneration system. An ee value of > 99% for 2-amino-2-phenylethanol and 1-phenyl-1, 2-ethanediol were simultaneously obtained with 50% conversion from R, S-2-amino-2-phenylethanol...
November 9, 2017: Biotechnology Letters
Khalid M Sumaily, Ahmed H Mujamammi
Disorders of protein metabolism are the most common diseases among discovered inherited metabolic disorders. Phenylketonuria (PKU), a relatively common disorder that is responsive to treatment, is an inherited autosomal recessive disorder caused by a deficiency in phenylalanine hydroxylase (PAH) or one of several enzymes mediating biosynthesis or regeneration of the PAH cofactor tetrahydrobiopterin. The objective of this review is to discuss therapeutic strategies that have recently emerged for curing patients with PKU, which have demonstrated promising improvements in managing these patients...
November 2017: International Journal of Health Sciences
Anna Kohl, Vishnu Srinivasamurthy, Dominique Böttcher, Johannes Kabisch, Uwe T Bornscheuer
The introduction of a three-enzyme cascade (comprising a cyclohexanone monooxygenase (CHMO), an alcohol dehydrogenase (ADH) and a lipase (CAL-A)) for the production of oligo-ε-caprolactone provided self-sufficiency with respect to NADPH-cofactor regeneration and reduced inhibiting effects on the central CHMO enzyme. For further optimization of cofactor regeneration, now a co-expression of CHMO and ADH in E. coli using a Duet™ vector was performed. This led to higher conversion values of the substrate cyclohexanol in whole-cell biocatalysis compared to an expression of both enzymes from two separate plasmids...
January 2018: Enzyme and Microbial Technology
Ryan A Kelley, Muayyad R Al-Ubaidi, Tirthankar Sinha, Ayse M Genc, Mustafa S Makia, Larissa Ikelle, Muna I Naash
The interface between the neural retina and the retinal pigment epithelium (RPE) is critical for several processes, including visual pigment regeneration and retinal attachment to the RPE. One of its most important functions is the exchange of metabolites between the photoreceptors and RPE because photoreceptor cells have very high energy demands, largely satisfied by oxidative metabolism. The riboflavin (RF) cofactors, flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) are two key cofactors involved in oxidative metabolism...
October 27, 2017: Journal of Biological Chemistry
Qingbao Ding, Ling Oua
BACKGROUND: Nucleoside 5'-triphosphates (NTPs) play an important role in cells in the transfer of phosphate groups or bioenergy. In vivo, they are ready to be produced, regenerated and consumed in different kinds of metabolic pathways, and their concentrations are strictly controlled. NTPs are useful reagents that take part in many biosynthetic processes. However, NTPs are expensive and unstable, which greatly increases the cost of the final product if a large amount of NTPs is used directly in biosynthesis...
October 24, 2017: Current Pharmaceutical Design
Diya Alsafadi, Safaa Alsalman, Francesca Paradisi
Enzymatic synthesis of enantiopure aromatic secondary alcohols (including substituted, hetero-aromatic and bicyclic structures) was carried out using halophilic alcohol dehydrogenase ADH2 from Haloferax volcanii (HvADH2). This enzyme showed an unprecedented substrate scope and absolute enatioselectivity. The cofactor NADPH was used catalytically and regenerated in situ by the biocatalyst, in the presence of 5% ethanol. The efficiency of HvADH2 for the conversion of aromatic ketones was markedly influenced by the steric and electronic factors as well as the solubility of ketones in the reaction medium...
November 7, 2017: Organic & Biomolecular Chemistry
Erin L McCarthy, Squire J Booker
Lipoyl synthase (LipA) catalyzes the last step in the biosynthesis of the lipoyl cofactor, which is the attachment of two sulfhydryl groups to C6 and C8 of a pendant octanoyl chain. The appended sulfur atoms derive from an auxiliary [4Fe-4S] cluster on the protein that is degraded during turnover, limiting LipA to one turnover in vitro. We found that the Escherichia coli iron-sulfur (Fe-S) cluster carrier protein NfuA efficiently reconstitutes the auxiliary cluster during LipA catalysis in a step that is not rate-limiting...
October 20, 2017: Science
Clifford S Morrison, William B Armiger, David R Dodds, Jonathan S Dordick, Mattheos A G Koffas
Industrial enzymatic reactions requiring 1,4-NAD(P)H2 to perform redox transformations often require convoluted coupled enzyme regeneration systems to regenerate 1,4-NAD(P)H2 from NAD(P) and recycle the cofactor for as many turnovers as possible. Renewed interest in recycling the cofactor via electrochemical means is motivated by the low cost of performing electrochemical reactions, easy monitoring of the reaction progress, and straightforward product recovery. However, electrochemical cofactor regeneration methods invariably produce adventitious reduced cofactor side products which result in unproductive loss of input NAD(P)...
October 10, 2017: Biotechnology Advances
Pengchao Wang, Xinwei Yang, Baixue Lin, Jianzhong Huang, Yong Tao
The efficiency of biocatalysis is often affected by an insufficient supply and regeneration of cofactors and redox equivalents. To alleviate this shortcoming, a cofactor self-sufficient system was developed for enhanced production of 2-phenylethanol (2-PE) in E. coli. A "bridge" between the amino acid and its corresponding alcohol was designed in the system using glutamate dehydrogenase. By coupling glutamate dehydrogenase with transaminase and alcohol dehydrogenase, the cosubstrate (2-oxoglutarate) and redox equivalents (NAD(P)H) were regenerated simultaneously, so that no external cofactor or redox source was required...
September 22, 2017: Metabolic Engineering
Huan Chen, Cui Cao, Anna Kulinich, Li Liu, Yong-Sam Jung, Josef Voglmeir
AIM AND OBJECTIVE: This study describes the design and evaluation of an expression vector for Pichia pastoris (pPICZαBHF), which is based on the commercial vector construct pPICZαB. MATERIAL AND METHOD: The performance of pPICZαBHF was evaluated with red fluorescence protein as a reporter. Additional His- and Flag-tags on the N-terminal ensure a simplified protein purification procedure. Transformation efficiency, expression level and plasmid maintenance were studied in order to test the functionality and usefulness of the constructed vector...
September 25, 2017: Combinatorial Chemistry & High Throughput Screening
Bronwyn E White, Caryn J Fenner, Martha S Smit, Susan T L Harrison
BACKGROUND: The regeneration of cofactors and the supply of alkane substrate are key considerations for the biocatalytic activation of hydrocarbons by cytochrome P450s. This study focused on the biotransformation of n-octane to 1-octanol using resting Escherichia coli cells expressing the CYP153A6 operon, which includes the electron transport proteins ferredoxin and ferredoxin reductase. Glycerol dehydrogenase was co-expressed with the CYP153A6 operon to investigate the effects of boosting cofactor regeneration...
September 20, 2017: Microbial Cell Factories
Yeounjoo Ko, Eunhee Seol, Balaji Sundara Sekar, Seongjin Kwon, Jaehyeon Lee, Sunghoon Park
Production of 3-hydroxypropionic acid (3-HP) or 1,3-propanediol (1,3-PDO) production from glycerol is challenging due to the problems associated with cofactor regeneration, coenzyme B12 synthesis, and the instability of pathway enzymes. To address these complications, simultaneous production of 3-HP and 1,3-PDO, instead of individual production of each compound, was attempted. With over-expression of an aldehyde dehydrogenase, recombinant Klebsiella pneumoniae could co-produce 3-HP and 1,3-PDO successfully...
November 2017: Bioresource Technology
Ya-Jun Wang, Wei Shen, Xi Luo, Zhi-Qiang Liu, Yu-Guo Zheng
t-Butyl 6-cyano-(3R,5R)-dihydroxyhexanoate ((3R,5R)-2) is a key chiral diol precursor of atorvastatin calcium (Lipitor®). We have constructed a Kluyveromyces lactis aldo-keto reductase mutant KlAKR-Y295W/W296L (KlAKRm) by rational design in previous research, which displayed high activity and excellent diastereoselectivity (dep  > 99.5%) toward t-butyl 6-cyano-(5R)-hydroxy-3-oxohexanoate ((5R)-1). To realize in situ cofactor regeneration, a robust KlAKRm and Exiguobacterium sibiricum glucose dehydrogenase (EsGDH) co-producer E...
August 26, 2017: Biotechnology Progress
Meng Wang, Yiou Zhou, Tianwei Tan
Diols, such as 1,3-propanediol (1,3-PDO) and 2,3-butanediol (2,3-BDO), have several promising properties for many synthetic reactions. Here, the cofactor engineering strategy, including the construction of Entner-Doudoroff pathway and transhydrogenase-based NADH regeneration system, was applied in producing diols from mixtures of glucose and glycerol. Entner-Doudoroff pathway had a high regeneration rate of NAD(P)H. This work described a strategy to administrate intracellular NADH/NAD(+) ratio and improved the concentration of diols...
August 18, 2017: Biotechnology Journal
Diederik J Opperman
Ene-reductases (ERs), or Old Yellow Enzymes, catalyze the asymmetric reduction of various activated alkenes. This class of biocatalysts is considered an attractive alternative to current chemical technologies for hydrogenation due to their high selectivity and specificity. Here the X-ray crystal structure of RmER, a "thermophilic"-like ER from Ralstonia (Cupriavidus) metallidurans, is reported. Unlike other members of this class of ERs, RmER is monomeric in solution which we previously related to its atypical elongated C-terminus...
August 22, 2017: Proteins
Fauziah Marpani, Zsuzsa Sárossy, Manuel Pinelo, Anne S Meyer
Enzymatic reduction of carbon dioxide (CO2 ) to methanol (CH3 OH) can be accomplished using a designed set-up of three oxidoreductases utilizing reduced pyridine nucleotide (NADH) as cofactor for the reducing equivalents electron supply. For this enzyme system to function efficiently a balanced regeneration of the reducing equivalents during reaction is required. Herein, we report the optimization of the enzymatic conversion of formaldehyde (CHOH) to CH3 OH by alcohol dehydrogenase, the final step of the enzymatic redox reaction of CO2 to CH3 OH, with kinetically synchronous enzymatic cofactor regeneration using either glucose dehydrogenase (System I) or xylose dehydrogenase (System II)...
December 2017: Biotechnology and Bioengineering
Francisco J Corpas, Juan B Barroso
Plant peroxisomes are recognized organelles that - with their capacity to generate greater amounts of H2O2 than other subcellular compartments - have a remarkable oxidative metabolism. However, over the last 15 years, new information has shown that plant peroxisomes contain other important molecules and enzymes, including nitric oxide (NO), peroxynitrite, a NADPH-recycling system, Ca(2+) and lipid-derived signals, such as jasmonic acid (JA) and nitro-fatty acid (NO2-FA). This highlights the potential for complex interactions within the peroxisomal nitro-oxidative metabolism, which also affects the status of the cell and consequently its physiological processes...
August 3, 2017: Journal of Cell Science
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