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Cofactor regeneration

Chandran Sathesh-Prabu, Sung Kuk Lee
The production of α,ω-dicarboxylic acids (DCAs) by whole-cell biocatalysis is often limited by cofactor regeneration. Here, ω-oxidation pathway genes (monooxygenase, alcohol dehydrogenase, and aldehyde dehydrogenase) were co-expressed with a xylose reductase (XR) gene to regenerate cofactors in an engineered Escherichia coli strain that co-metabolizes glucose and xylose. The resulting strain exhibited a 180% increase in DCA production compared with the control strain without XR, and produced xylitol in the presence of xylose...
March 14, 2018: Journal of Agricultural and Food Chemistry
Godwin Sokpor, Eman Abbas, Joachim Rosenbusch, Jochen F Staiger, Tran Tuoc
The postnatal mammalian olfactory epithelium (OE) represents a major aspect of the peripheral olfactory system. It is a pseudostratified tissue that originates from the olfactory placode and is composed of diverse cells, some of which are specialized receptor neurons capable of transducing odorant stimuli to afford the perception of smell (olfaction). The OE is known to offer a tractable miniature model for studying the systematic generation of neurons and glia that typify neural tissue development. During OE development, stem/progenitor cells that will become olfactory sensory neurons and/or non-neuronal cell types display fine spatiotemporal expression of neuronal and non-neuronal genes that ensures their proper proliferation, differentiation, survival, and regeneration...
March 12, 2018: Molecular Neurobiology
Alice E Parnell, Silja Mordhorst, Florian Kemper, Mariacarmela Giurrandino, Josh P Prince, Nikola J Schwarzer, Alexandre Hofer, Daniel Wohlwend, Henning J Jessen, Stefan Gerhardt, Oliver Einsle, Petra C F Oyston, Jennifer N Andexer, Peter L Roach
Inorganic polyphosphate is a ubiquitous, linear biopolymer built of up to thousands of phosphate residues that are linked by energy-rich phosphoanhydride bonds. Polyphosphate kinases of the family 2 (PPK2) use polyphosphate to catalyze the reversible phosphorylation of nucleotide phosphates and are highly relevant as targets for new pharmaceutical compounds and as biocatalysts for cofactor regeneration. PPK2s can be classified based on their preference for nucleoside mono- or diphosphates or both. The detailed mechanism of PPK2s and the molecular basis for their substrate preference is unclear, which is mainly due to the lack of high-resolution structures with substrates or substrate analogs...
March 12, 2018: Proceedings of the National Academy of Sciences of the United States of America
Joshua D Bryant, Shannon R Sweeney, Enrique Sentandreu, Minhye Shin, Helene Ipas, Blerta Xhemalce, Jessica Momb, Stefano Tiziani, Dean R Appling
One-carbon (1C) metabolism is a universal folate-dependent pathway essential for de novo purine and thymidylate synthesis, amino acid interconversion, universal methyl-donor production, and regeneration of redox cofactors. Homozygous deletion of the 1C pathway gene Mthfd1l encoding methylenetetrahydrofolate dehydrogenase (NADP+ dependent) 1-like, which catalyzes mitochondrial formate production from 10-formyltetrahydrofolate, results in 100% penetrant embryonic neural tube defects (NTDs), underscoring the central role of mitochondrially derived formate in embryonic development and providing a mechanistic link between folate and NTDs...
February 26, 2018: Journal of Biological Chemistry
Hui-Lei Yu, Tuo Li, Fei-Fei Chen, Xiao-Jing Luo, Aitao Li, Chao Yang, Gao-Wei Zheng, Jian-He Xu
Biocatalytic C-H amination is one of the most challenging tasks. C-H amination reaction can hardly be driven efficiently by solely one enzyme so far. Thus, enzymatic synergy represents an alternative strategy. Herein, we report an "Artificially Bioamination Pathway" for C-H amination of cyclohexane as a model substrate. Three enzymes, a monooxygenase P450BM3 mutant, an alcohol dehydrogenase ScCR from Streptomyces coelicolor and an amine dehydrogenase EsLeuDH from Exiguobactertium sibiricum, constituted a clean cascade reaction system with easy product isolation...
February 22, 2018: Metabolic Engineering
Erzheng Su, Yang Meng, Chenxi Ning, Xiaoqiang Ma, Senwen Deng
Magnetic Fe 3 O 4 nanoparticles were prepared and embedded into the Combi-CLEAs to produce the magnetic Combi-CLEAs in this work. The process for magnetic Combi-CLEAs preparation was optimized, and its properties were investigated. The optimum temperature, thermal stability and optimum pH of magnetic Combi-CLEAs were similar to those of Combi-CLEAs. The catalytic performance of magnetic Combi-CLEAs was tested with the biosynthesis of (S)-ethyl 4-chloro-3-hydroxybutyrate ((S)-CHBE). Magnetic Combi-CLEAs could tolerate higher substrate concentration in the biphasic system...
February 13, 2018: Journal of Biotechnology
Jinqiu Wei, Yujiao Zhang, Zhan Li, Ximin Wang, Linlin Chen, Juanjuan Du, Jing Liu, Ju Liu, Yinglong Hou
BACKGROUND/AIMS: Cardiac autonomic nerve remodeling (ANR) is an important mechanism of atrial fibrillation (AF).GTP cyclohydrolase I (GTPCH-1), encoded by GCH1, is the rate-limiting enzyme in de novosynthesis of tetrahydrobiopterin (BH4), an essential cofactor for nitric oxide (NO) synthesis. Previous studies reported that increased BH4 and NO content negatively regulated nerve regeneration. This study investigated effects of GCH1on ANR via BH4 pathway, regulated by microRNA-206 (miR-206)...
February 13, 2018: Pacing and Clinical Electrophysiology: PACE
Feng Li, Yuanxiu Li, Li-Ming Sun, Xiaoli Chen, Xingjuan An, Changji Yin, Yingxiu Cao, Hui Wu, Hao Song
Efficient extracellular electron transfer (EET) of exoelectrogens is essentially for practical applications of versatile bio-electrochemical systems. Intracellular electrons flow from NADH to extracellular electron accepters via EET pathways. However, it was yet established how the manipulation of intracellular NADH impacted the EET efficiency. Strengthening NADH regeneration from NAD + , as a feasible approach for cofactor engineering, has been used in regulating the intracellular NADH pool and the redox state (NADH/NAD + ratio) of cells...
February 11, 2018: ACS Synthetic Biology
Lei Han, Bo Liang, Jianxia Song
As an important cofactor, NADH is essential for most redox reactions and biofuel cells. However, supply of exogenous NADH is challenged, due to the low production efficiency and high cost of NADH regeneration system, as well as low stability of NADH. Here, we constructed a novel cell surface multi-enzyme co-display system with ratio- and space-controllable manner as exogenous NADH regeneration system for the sustainable NADH production from low-cost biomass. Dockerin-fused glucoamylase (GA) and glucose dehydrogenase (GDH) were expressed and assembled on the engineered bacterial surfaces, which displayed protein scaffolds with various combinations of different cohesins...
January 10, 2018: Journal of Industrial Microbiology & Biotechnology
Andrew Gomm, Elaine O'Reilly
Amine transaminases are important biocatalysts for the synthesis of chiral primary amines. Unlike many enzymes that have been employed for the synthesis of optically active amines, amine transaminases are capable of asymmetric synthesis and do not rely on costly cofactors that must be regenerated in situ. However, their application as general catalysts for the preparation of amines is hampered by a limited substrate scope, substrate and (co)product inhibition and difficulties associated with displacing challenging reaction equilibrium...
January 4, 2018: Current Opinion in Chemical Biology
Han Li, Wenhua Xiao, Panpan Xie, Liangyu Zheng
Herein we established co-immobilized methods for enoate reductases (ERs) and glucose dehydrogenase (GDH), forming a cofactor regeneration system. In cross-linked enzyme aggregates (CLEAs), ammonium sulfate and oxidized dextran were selected as a precipitant and a cross-linker, respectively. In biomimetic immobilization (BI), ER-GDH-silica particles (ER-GDH-SPs) were rapidly formed through a one-step approach by using a silicic acid precursor. Under the optimal conditions, the ER activity recovery in ER-GDH-CLEAs and ER-GDH-SPs were 44...
February 2018: Enzyme and Microbial Technology
Fatemeh Seifar, Mohammad Khalili, Habib Khaledyan, Shirin Amiri Moghadam, Azimeh Izadi, Amirreza Azimi, Seied Kazem Shakouri
OBJECTIVES: α-lipoic acid (ALA) is a natural antioxidant which acts as a cofactor of bioenergetic mitochondrial enzymes. Along with its mitochondrial action, ALA and its reduced form have many biological functions resulting in a wide variety of actions such as anti-inflammation and antioxidant protection, scavenging reactive oxygen species, regenerating other antioxidant agents, such as vitamins C and E, and cytosolic glutathione, chelating the transitional metal ions (e.g. iron and copper), and modulating the signal transduction of nuclear factor...
November 29, 2017: Nutritional Neuroscience
Diana Uhrich, Jan von Langermann
The preparation and characterization of UV-cured polyurethane-based materials for the mild inclusion immobilization of enzymes was investigated. Full curing of the polymer precursor/enzyme solution mixture was realized by a short irradiation with UV-light at ambient temperatures. The included aqueous enzyme solution remains highly dispersed in the polymer material with an even size distribution throughout the polymer material. The presented concept provides stable enzyme compartments which were applied for an alcohol dehydrogenase-catalyzed reduction reaction in organic solvents...
2017: Frontiers in Microbiology
Jian Wang, Yaping Yang, Ruihua Zhang, Xiaolin Shen, Zhenya Chen, Jia Wang, Qipeng Yuan, Yajun Yan
2-Methylsuccinic acid (2-MSA) is a C5 branched-chain dicarboxylate that serves as an attractive synthon for the synthesis of polymers with extensive applications in coatings, cosmetic solvents and bioplastics. However, the lack of natural pathways for 2-MSA biosynthesis has limited its application as a promising bio-replacement. Herein, we conceived a non-natural three-step biosynthetic route for 2-MSA, via employing the citramalate pathway in combination with enoate reductase-mediated bioreduction of the pathway intermediate citraconate...
January 2018: Metabolic Engineering
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
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