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Superoxide anion (O 2·− ) is the primary species of the reactive oxygen species (ROS), resulting from the metabolism of O 2 in the living organisms. Its dynamic changes can provide broad implications in physiological and pathological conditions. Therefore, the analytical methods that can determine O 2·− real-time and in vivo are receiving more and more attention....
The hemicelluloses were separated from the cottonseed coat and degraded with Pulpzyme HC. The digestion degree value was calculated by the equation depended on the release of reducing sugars concentration which was determined from DNS fitting curve equation. The optimum enzyme reaction temperature was 60°C and pH was 5.5. The duration of 80 min was chose as the most suitable enzymolysis time. The...
Functional feruloylated lipids, which are composed of 1(3)-feruloyl-monooleyl-glycerol (FMOG) and 1(3)-feruloyl-dioleyl-glycerol (FDOG), was prepared through the lipase-catalyzed irreversible transesterification between vinyl feruate (VF) and triolein (TO) in toluene. The nuclear magnetic resonance (NMR) and electrospray ionization-mass spectroscopy (ESI-MS) analysis confirmed the structure of VF...
A kind of polymeric prodrug of ibuprofen with glucose pendant was prepared through chemo-enzymatic method. The obtained polymeric prodrug was characterized by FT-IR, NMR and GPC. The molecular weight of the polymeric prodrug reached 2.126 × 104. Furthermore, the in vitro release behaviors of ibuprofen (raw drug) and the polymeric prodrug were investigated in pH 7.4 buffer solution at 37°C. It was...
With the rapid development of the global industries and the impact this is having on atmospheric and environmental conditions, increased radiations factors are becoming more problematic. This study describes the application of a kind of new green solvent composed of [BMIM] + Cl-) + ([BMIM] + BF4-) ionic liquids by wet spinning to prepare papain-carried wood cellulose fibers. And the dissolution process...
4-Hydroxyphenylacetic acid (4-HPA) can inhibit monophenolase (IC50=0.79 mM) and activate diphenolase of mushroom tyrosinase with its increasing concentrations. The activation kinetics, analyzed by Lineweaver-Burk plots, indicated 4-HPA to be a competitive and uncompetitive mixed-type activator of diphenolase when L-DOPA was used as substrate. 4-HPA can not only inhibit the oxy form but also activate...
The kinetic resolution of secondary alcohols catalyzed by Candidaantarctica lipase was studied using vinyl acetate as acyl donor in propylene carbonate. The effects of the reaction conditions included solvent, temperature, acyl donor and organic base. In the reactions, the enantioselectivity of Candidaantarctica lipase increased with increasing the reaction time and the addition of triethylamine...
This study demonstrates that Aminoethylisothiourea (AET), a potent inhibitor of inducible nitric oxide synthase (NOS), is an irreversible competitive inhibitor of the diphenolase activity of mushroom tyrosinase when L-DOPA was assayed spectrophotometrically in vitro. The inhibition of diphenolase activity of tyrosinase by AET showed positive kinetic cooperativity which arose from the protection of...
Papain (EC 3.4.22.2) has been chemically modified using two reagents including different anhydrides of maleic and poly-maleic acids. The average ratio of modified-NH2 was tested by trinitrobenzenesulfonic acid (TNBS) method. The native and modified papain were purified by dialysis and their structures were characterized by FTIR. The factor related with the activity of the modified papain, such as...
A facile procedure combining enzymatic resolution with chemical polymerization was developed to prepare optically active polymeric prodrug containing glucose. Polymerizable optically active (R)-1-O-vinyladipoyl-chlorphenesin ((R)-OVAC) was obtained in excellent optically purity (ee>99.9%) and high yield (~50%) in short time, and optically active (S)-N-vinyladipoyl-propranolol ((S)-NVAP) was obtained...
Electrospun nylon-6 nanofibrous membrane with fiber diameters in the range of 50-200 nm were prepared and employed as affinity membrane material for papain adsorption due to their excellent chemical and thermal resistance as well as high wettability. In this work, covalent coupling of chitosan (CS) to activated nylon membrane was performed after the reaction of the nanofibrous nylon membrane with...
A facile enzymatic synthesis approach to prepare novel ester of ferulic acid through the lipase-catalyzed transesterification reaction of ethyl ferulate (EF) with tributyrin (TB) was investigated. The 1H NMR, 13C NMR and EI-MS analysis confirmed the formation of the end product, namely 1(3)-feruloyl-dibutyryl-glycerol (FDB). The influences of different enzyme source, enzyme loading, and water activity...
Nylon membranes are first hydrolyed with dilute HCl and then treated with chitosan before being used as the affinity carrier. Papain as a ligand has been immobilized on the activated membranes with glutaraldehyde as a crosslinking agent. The factors involving with the activity of immobilized papain, such as concentration of glutaraldehyde, pH, temperature, reaction time, and the amount of added papain...
The application of cellulases in various industries demands highly stable enzymes, able to perform at extreme pH values and temperatures. In this study, the cellulase, which was immobilized on the chitosan-coated magnetic nanoparticles modified with alpha-ketoglutaric acid (alpha-KA-CCMNPs), exhibited a broader pH range of high activity and the loss of the activity of immobilized cellulase was lower...
Utilizing whole cell as biocatalyst instead of free or immobilized enzyme is a potential way to reduce the cost of catalyst in enzyme-catalyzed beta-D-2', 3'-unsaturated-5-fluorocytidine (D-D4FC). In this paper, D-D4FC was successfully synthesized by the whole cell of Lactobacillus helveticus (ATCC10697) for the first time. Several experimental parameters including reaction time, concentration of...
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