18,342 results match your criteria enzymatic mechanism

Proteomic response of Escherichia coli to a membrane lytic and iron chelating truncated Amaranthus tricolor defensin.

BMC Microbiol 2021 Apr 12;21(1):110. Epub 2021 Apr 12.

Department of Chemistry, University of North Carolina at Chapel Hill, 125 South Rd. CB#3290, Chapel Hill, NC, 27599, USA.

Background: Plant defensins are a broadly distributed family of antimicrobial peptides which have been primarily studied for agriculturally relevant antifungal activity. Recent studies have probed defensins against Gram-negative bacteria revealing evidence for multiple mechanisms of action including membrane lysis and ribosomal inhibition. Herein, a truncated synthetic analog containing the γ-core motif of Amaranthus tricolor DEF2 (Atr-DEF2) reveals Gram-negative antibacterial activity and its mechanism of action is probed via proteomics, outer membrane permeability studies, and iron reduction/chelation assays. Read More

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Structures of an engineered phospholipase D with specificity for secondary alcohol transphosphatidylation: Insights into plasticity of substrate binding and activation.

Biochem J 2021 Apr 12. Epub 2021 Apr 12.

University of Western Australia, Perth, Australia.

Phospholipase D (PLD) is an enzyme useful for the enzymatic modification of phospholipids.  In the presence of primary alcohols, the enzyme catalyses transphosphatidylation of the head group of phospholipid substrates to synthesize a modified phospholipid product.  However, the enzyme is specific for primary alcohols and thus the limitation of the molecular size of the acceptor compounds has restricted the type of phospholipid species that can be synthesised. Read More

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Effects of enzymatic reaction on the generation of key aroma volatiles in shiitake mushroom at different cultivation substrates.

Food Sci Nutr 2021 Apr 26;9(4):2247-2256. Epub 2021 Feb 26.

Institute of Edible Fungi Shanghai Academy of Agricultural Sciences National Engineering Research Center of Edible Fungi Key Laboratory of Edible Fungi Resources and Utilization (South) Ministry of Agriculture Shanghai China.

Aroma is an important factor affecting mushroom character and quality. According to the different reaction pathway, the key aroma metabolites (sulfur and eight-carbon volatiles) formation can be classified into enzymatic reactions and nonenzymatic reactions. Aroma volatiles are generated from precursors via the biocatalytic activities of various synthases during the growth stages of shiitake mushrooms. Read More

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Crystal structure of higher plant heme oxygenase-1 and its mechanism of interaction with ferredoxin.

J Biol Chem 2020 Dec 24;296:100217. Epub 2020 Dec 24.

Institute for Protein Research, Osaka University, Suita, Osaka, Japan; Department of Macromolecular Science, Osaka University, Toyonaka, Osaka, Japan. Electronic address:

Heme oxygenase (HO) converts heme to carbon monoxide, biliverdin, and free iron, products that are essential in cellular redox signaling and iron recycling. In higher plants, HO is also involved in the biosynthesis of photoreceptor pigment precursors. Despite many common enzymatic reactions, the amino acid sequence identity between plant-type and other HOs is exceptionally low (∼19. Read More

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December 2020

The high adaptability of Hyphantria cunea larvae to cinnamic acid involves in detoxification, antioxidation and gut microbiota response.

Pestic Biochem Physiol 2021 May 25;174:104805. Epub 2021 Feb 25.

School of Forestry, Northeast Forestry University, Harbin 150040, PR China; Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, Harbin 150040, PR China. Electronic address:

Hyphantria cunea is one of the most destructive invasive agricultural and forest pests worldwide. In order to better understand the adaptation mechanism of H. cunea larvae to secondary metabolites of their highly diversified host plants, the physiological function and detoxification ability of midgut, as well as the gut microbial community were investigated in H. Read More

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Stability comparison of four lipases and catalytic mechanism during the synthesis of 1,3-di-oleic-2-medium chain triacylglycerols in a trace water-in-oil system: Experimental analyses and computational simulations.

J Food Biochem 2021 Apr 9:e13667. Epub 2021 Apr 9.

State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, China.

In the present study, a kind of structured lipids, namely 1,3-di-oleic-2-medium chain (OMO) triacylglycerols, were synthesized through lipase-catalyzed reactions using coconut oil and rapeseed acid as materials in a trace water-in-oil system. Experimental analysis and computational simulations were undertaken to compare the stability of four lipases including Lipozyme RMIM, Lipozyme TLIM, Novozym 435, and Aspergillus oryzae immobilized lipase (AOIM), and illustrate catalytic mechanism of Novozym 435 during the synthesis of OMO. Fourier transform infrared and molecular dynamics simulation results demonstrated that a decrease in ordered structure (α-helix and β-sheet) led to a reduction in enzyme activity. Read More

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Effect of Leu277 on Disproportionation and Hydrolysis Activity in NO2 Cyclodextrin Glucosyltransferase.

Appl Environ Microbiol 2021 Apr 9. Epub 2021 Apr 9.

State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China

The disproportionation activity of cyclodextrin glucosyltransferase (CGTase, EC 2.4.1. Read More

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An NAD+/NMN balancing act by SARM1 and NMNAT2 controls axonal degeneration.

Neuron 2021 04;109(7):1067-1069

Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1085, USA. Electronic address:

Axonal degeneration is controlled by the TIR domain NADase SARM1. In this issue of Neuron, Figley et al. (2021) reveal a key regulatory mechanism that controls SARM1's enzymatic activity, providing insight into how NAD+ biosynthesis by the NMNAT2 enzyme protects axons, and a new therapeutic path to tune SARM1 activity. Read More

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Preliminary results of neutron and X-ray diffraction data collection on a lytic polysaccharide monooxygenase under reduced and acidic conditions.

Acta Crystallogr F Struct Biol Commun 2021 Apr 31;77(Pt 4):128-133. Epub 2021 Mar 31.

Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695, USA.

Lytic polysaccharide monooxygenases (LPMOs) are copper-center enzymes that are involved in the oxidative cleavage of the glycosidic bond in crystalline cellulose and other polysaccharides. The LPMO reaction is initiated by the addition of a reductant and oxygen to ultimately form an unknown activated copper-oxygen species that is responsible for polysaccharide-substrate H-atom abstraction. Given the sensitivity of metalloproteins to radiation damage, neutron protein crystallography provides a nondestructive technique for structural characterization while also informing on the positions of H atoms. Read More

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Posttranslational regulation of FOXA1 by Polycomb and BUB3/USP7 deubiquitin complex in prostate cancer.

Sci Adv 2021 Apr 7;7(15). Epub 2021 Apr 7.

Division of Hematology/Oncology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.

Forkhead box protein A1 (FOXA1) is essential for androgen-dependent prostate cancer (PCa) growth. However, how FOXA1 levels are regulated remains elusive and its therapeutic targeting proven challenging. Here, we report FOXA1 as a nonhistone substrate of enhancer of zeste homolog 2 (EZH2), which methylates FOXA1 at lysine-295. Read More

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Trehalose alleviates high-temperature stress in Pleurotus ostreatus by affecting central carbon metabolism.

Microb Cell Fact 2021 Apr 7;20(1):82. Epub 2021 Apr 7.

Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.

Background: Trehalose, an intracellular protective agent reported to mediate defense against many stresses, can alleviate high-temperature-induced damage in Pleurotus ostreatus. In this study, the mechanism by which trehalose relieves heat stress was explored by the addition of exogenous trehalose and the use of trehalose-6-phosphate synthase 1 (tps1) overexpression transformants.

Results: The results suggested that treatment with exogenous trehalose or overexpression of tps1 alleviated the accumulation of lactic acid under heat stress and downregulated the expression of the phosphofructokinase (pfk) and pyruvate kinase (pk) genes, suggesting an ameliorative effect of trehalose on the enhanced glycolysis in P. Read More

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H3K4 Methyltransferase Smyd3 Mediates Vascular Smooth Muscle Cell Proliferation, Migration, and Neointima Formation.

Arterioscler Thromb Vasc Biol 2021 Apr 8:ATVBAHA121314689. Epub 2021 Apr 8.

State Key Laboratory of Quality Research in Chinese Medicine and School of Pharmacy, Macau University of Science and Technology, Macau (D.Y., Y.Z.Z.).

Objective: Smyd3 (SET and MYND domain-containing protein 3) is an H3K4 (histone H3 lysine 4) dimethyltransferase and trimethyltransferase that activates the transcription of oncogenes and cell cycle genes in human cancer cells. We discovered its overexpression in proliferative vascular smooth muscle cells (VSMCs). However, whether Smyd3 plays a role in vascular remodeling remains unanswered. Read More

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Criticality of a conserved tyrosine residue in the SpeG protein from Escherichia coli.

Protein Sci 2021 Apr 7. Epub 2021 Apr 7.

Department of Chemistry & Biochemistry, San Francisco State University, California, USA.

The SpeG spermidine/spermine N-acetyltransferase (SSAT) from Escherichia coli belongs to the Gcn5-related N-acetyltransferase (GNAT) superfamily of proteins. In vitro characterization of this enzyme shows it acetylates the polyamines spermine and spermidine, with a preference toward spermine. This enzyme has a conserved tyrosine residue (Y135) that is found in all SSAT proteins and many GNAT functional subfamilies. Read More

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Antityrosinase Mechanism and Antimelanogenic Effect of Arbutin Esters Synthesis Catalyzed by Whole-Cell Biocatalyst.

J Agric Food Chem 2021 Apr 6. Epub 2021 Apr 6.

Department of Spine Surgery, Center for Orthopaedic Surgery, The Third Affiliated Hospital of Southern Medical University, Academy of Orthopedics of Guangdong Province, Guangzhou 510630, China.

Tyrosinase is a key enzyme responsible for enzymatic browning of fruits and vegetables and skin disorders due to overproduction of melanin. Arbutin is an inhibitor of tyrosinase; however, its high polarity and weak transdermal absorption capacity limit its applications. In this paper, a green solvent system was developed to successfully synthesize arbutin esters with improved liposolubilities (Clog values = 0. Read More

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Tuneable control over organocatalytic activity through host guest chemistry.

Angew Chem Int Ed Engl 2021 Apr 5. Epub 2021 Apr 5.

Delft University of Technology, Department of Chemical Engineering, Julianalaan 136, 2628BL, Delft, NETHERLANDS.

Dynamic regulation of chemical reactivity is important in many complex chemical reaction networks such as cascade reactions and signal transduction processes. Signal responsive catalysts could play a crucial role in regulating these reaction pathways, a concept that is universal to controlling reactions networks by enzymatic catalysis in nature. However, synthetic catalysts with controllable activity are rare. Read More

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Design, synthesis and evaluation of anti-proliferative activity of 2-aryl-4-aminoquinazoline derivatives as EGFR inhibitors.

Bioorg Chem 2021 Mar 22;112:104848. Epub 2021 Mar 22.

Jiangxi Provincial Key Laboratory of Drug Design and Evaluation, School of Pharmacy, Jiangxi Science & Technology Normal University, 605 Fenglin Road, Nanchang 330013, China. Electronic address:

A class of 2-aryl-4-aminoquinazoline derivatives (7a-7j, 8a-8h, 9a-9h and 10a-10k) were designed, synthesized and evaluated as EGFR inhibitors. The anti-proliferative activity of compounds in vitro showed that compound 9e was considered to be a promising derivative. Compared with the lead compound Angew2017-7634-1, 9e exhibited excellent inhibitory activity against A549, NCI-H460 and H1975 cell lines, with IC values of 14. Read More

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Structural and molecular dynamics investigations of ligand stabilization via secondary binding site interactions in GH11 xylanase.

Comput Struct Biotechnol J 2021 7;19:1557-1566. Epub 2021 Mar 7.

Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São-carlense 400, 13566-590 São Carlos, SP, Brazil.

Glycoside hydrolases (GHs) are essential for plant biomass deconstruction. GH11 family consist of endo-β-1,4-xylanases which hydrolyze xylan, the second most abundant cell wall biopolymer after cellulose, into small bioavailable oligomers. Structural requirements for enzymatic mechanism of xylan hydrolysis is well described for GH11 members. Read More

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Current understanding of the inhibition factors and their mechanism of action for the lignocellulosic biomass hydrolysis.

Bioresour Technol 2021 Mar 27;332:125042. Epub 2021 Mar 27.

Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City, Taiwan. Electronic address:

Biorefining of lignocellulosic biomass is a relatively new concept but it has strong potential to develop and partially replace the fossil derived fuels and myriad of value products to subsequently reduce the greenhouse gas emissions. However, the energy and cost intensive process of releasing the entrapped fermentable sugars is a major challenge for its commercialization. Various factors playing a detrimental role during enzymatic hydrolysis of biomass are inherent recalcitrance of lignocellulosic biomass, expensive enzymes, sub-optimal enzyme composition, lack of synergistic activity and enzyme inhibition caused by various inhibitors. Read More

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The Mediator complex kinase module is necessary for fructose regulation of liver glycogen levels through induction of glucose-6-phosphatase catalytic subunit (G6pc).

Mol Metab 2021 Mar 31:101227. Epub 2021 Mar 31.

Departments of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461 USA; Developmental and Molecular Biology, and Albert Einstein College of Medicine, Bronx, NY 10461 USA; Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, NY 10461 USA.

Objective: Liver glycogen levels are dynamic and highly regulated by nutrient availability as the levels decrease during fasting and are restored during the feeding cycle. However, feeding in the presence of fructose in water suppressed glycogen accumulation in the liver by up-regulating the expression of glucose-6-phosphatase catalytic subunit (G6pc) gene although the exact mechanism is unknown. We generated liver specific knockout of MED13 mice that lack the transcriptional Mediator complex kinase module to examine its effect on transcriptional activation of inducible target gene expression, such as the ChREBP- and FOXO1-dependent control of the G6pc gene promoter. Read More

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Recent Developments in Enzymatic Antioxidant Defence Mechanism in Plants with Special Reference to Abiotic Stress.

Biology (Basel) 2021 Mar 26;10(4). Epub 2021 Mar 26.

Academy of Biology and Biotechnology, Southern Federal University, 344090 Rostov-on-Don, Russia.

The stationary life of plants has led to the evolution of a complex gridded antioxidant defence system constituting numerous enzymatic components, playing a crucial role in overcoming various stress conditions. Mainly, these plant enzymes are superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), glutathione peroxidase (GPX), glutathione reductase (GR), glutathione S-transferases (GST), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase (DHAR), which work as part of the antioxidant defence system. These enzymes together form a complex set of mechanisms to minimise, buffer, and scavenge the reactive oxygen species (ROS) efficiently. Read More

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A Rational Approach for the Production of Highly Soluble and Functional Sunflower Protein Hydrolysates.

Foods 2021 Mar 19;10(3). Epub 2021 Mar 19.

Laboratoire Réactions et Génie des Procédés, Université de Lorraine, Unité Mixte de Recherche CNRS/Ministère (UMR) 7274, LRGP, F-54500 Vandœuvre-lès-Nancy, France.

Exploitation of plant proteins as an alternative to animal proteins currently presents an important challenge for food industries. In this contribution, total sunflower protein isolate from cold press meal was used as a starting material for the generation of highly soluble and functional hydrolysates that could be used in various food formulations. To do this, a rational and complete approach of controlled hydrolysis was implemented using the individual Alcalase and Prolyve enzymes. Read More

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