Journal of Molecular Catalysis B: Enzymatic This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.

Diffusion effects of bovine serum albumin on cross-linked aggregates of catalase
Publication date: Available online 6 August 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Agnes Cristina Oliveira Mafra, Willian Koop, Maisa Bontorin Beltrame, Raquel de Lima Camargo Giordano, Marcelo Perencin de Arruda Ribeiro, Paulo Waldir Tardioli Stabilization of multimeric enzymes is one of the major challenges in biocatalysis since dissociation of subunits can inactivate the enzyme. Particularly, catalase that breaks down hydrogen peroxide in water and molecular oxygen is an enzyme difficult to stabilize by conventional immobilization techniques, because it is a tetrameric structure conta...
Source: Journal of Molecular Catalysis B: Enzymatic - August 7, 2016 Category: Biochemistry Source Type: research

The Influence of Synthesis Conditions on Enzymatic Activity of Enzyme-Inorganic Hybrid Nanoflowers
Publication date: Available online 2 August 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Yue Li, Xu Fei, Liwen Liang, Jing Tian, Longquan Xu, Xiuying Wang, Yi Wang In this work, we synthesized hierarchical flower-like structures by using lipase and papain as organic components and Cu3(PO4)2·3H2O as the inorganic component. These hybrid-nanoflower structures were confirmed by Fourier transform infrared spectroscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy. By changing the synthesis conditions, including enzyme concentration, pH, and temperature for the nanoflowers, we can ...
Source: Journal of Molecular Catalysis B: Enzymatic - August 3, 2016 Category: Biochemistry Source Type: research

Laccase-catalyzed treatment of ketoconazole, identification of biotransformed metabolites, determination of kinetic parameters, and evaluation of micro-toxicity
Publication date: Available online 27 July 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Aliakbar Yousefi-Ahmadipour, Maryam Bozorgi-Koshalshahi, Mehdi Mogharabi, Mohsen Amini, Mahmoud Ghazi-Khansari, Mohammad Ali Faramarzi Ketoconazole is widely used in human and veterinary medicine; however, residual amounts of this antifungal agent have potential adverse effects on ecological health. The present study describes the use of laccase from Trametes versicolor for biotransformation and detoxification of ketoconazole. The substrate was removed at optimum conditions of 45°C, pH 4.5, incubat...
Source: Journal of Molecular Catalysis B: Enzymatic - July 27, 2016 Category: Biochemistry Source Type: research

Removal of lactose in crude galacto-oligosaccharides by β-galactosidase from Kluyveromyces lactis
Publication date: Available online 25 July 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Luciana Santibáñez, Lucía Fernández-Arrojo, Cecilia Guerrero, Francisco J. Plou, Andrés Illanes In order to remove the residual lactose in crude galacto-oligosaccharides (GOS), different commercial soluble β-galactosidases from Kluyveromyces lactis (Lactozym Pure 6500L, Maxilact L2000, Lactase NL and Biolactasa-NL) and reaction conditions (temperature, total carbohydrate concentration and enzyme:substrate mass ratio) were evaluated. To select the best biocatalyst, the hydrolytic activity on o-NP...
Source: Journal of Molecular Catalysis B: Enzymatic - July 25, 2016 Category: Biochemistry Source Type: research

Kinetic model of biodiesel production catalyzed by free liquid lipase from Thermomyces lanuginosus
Publication date: Available online 25 July 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Mohamad Firdaus Mohamad Yusoff, Jesper Brask, Per Munk Nielsen, Zheng Guo, Sergey Fedosov Conversion of plant oil to biodiesel was investigated using liquid lipase from Thermomyces lanuginosus. Presence of 2–3% water was necessary to preserve the enzymatic activity under methanolysis (3×0.5 equivalents of MeOH added in steps). Several individual reaction blocks were investigated and became the individual segments of the full kinetic scheme. Additional reaction schemes were introduced to imitate cha...
Source: Journal of Molecular Catalysis B: Enzymatic - July 25, 2016 Category: Biochemistry Source Type: research

Role of Leu188 in the Fatty Acid Hydroxylase Activity of CYP102A1 from Bacillus megaterium
In this study, we examined the role of the L188 residue by comparing the catalytic activities of wild-type CYP102A1 and 19 mutants of L188. The mutants were made with site-directed mutagenesis and functionally expressed in Escherichia coli. The enzymatic properties of the mutants for a set of fatty acids (C10-C16) were compared to the properties of the wild-type. L188Q and L188P mutants showed especially strong increases in hydroxylase activity toward C10-C13 fatty acids, although they did not have activity changes for C14-C16 fatty acids. Although most mutants showed very similar overall hydroxylation rates for myristic a...
Source: Journal of Molecular Catalysis B: Enzymatic - July 25, 2016 Category: Biochemistry Source Type: research

Production, purification and immobilization of pectinase from Aspergillus ibericus onto functionalized nanoporous activated carbon (FNAC) and its application on treatment of pectin containing wastewater
In this study response surface methodology (RSM) was employed to determine optimum conditions for the production of pectinase from citrus pectin. The optimum conditions for the production of pectinase were found to be pH, 4.0; temperature, 40°C; incubation time, 120h and substrate concentration (Citrus Pectin), 2% (w/v). The maximum activity of pectinase at optimum conditions was found to be 69.9UmL−1. The purification by DEAE-Cellulose increased the specific activity of pectinase by about 10.1 fold from 64 to 650Umg−1 protein. The molecular weight of the purified pectinase was found to be 41kDa and 43kDa. The purifie...
Source: Journal of Molecular Catalysis B: Enzymatic - July 25, 2016 Category: Biochemistry Source Type: research

Enantio- and diastereoselective acylation of prochiral hydroxyl group of pyrimidine acyclonucleosides
Publication date: Available online 25 July 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Renata Kołodziejska, Marcin Kwit, Renata Studzińska, Maciej Jelecki The transesterification reaction of series pyrimidine acyclonucleosides was carried out with lipase (EC 3.1.1.3) Amano PS from Burkholderia cepacia (BCL) as biocatalyst. The BCL-mediated acylation of prochiral groups of diols produced the corresponding monoesters in high yield and with enantiomeric/diasteromeric excess from 77 to 99%. The lipase BCL enabled desymmetrization of pro-R hydroxyl groups and gave (2R)-monoesters. Absolute c...
Source: Journal of Molecular Catalysis B: Enzymatic - July 25, 2016 Category: Biochemistry Source Type: research

Isolation, purification and characterization of a salt-active and organic-solvent-thermostable phenylalanine dehydrogenase from Bacillus nanhaiensis DSF-15A2
Conclusions The results indicated that the affinity of enzyme, substrate and co-factor and the catalytic efficiency can be significantly improved by organic solvents, suggesting that the BnPheDH had great application value in organic phase or aqueous-organic phase catalytic reaction, and it would be used as an robust biocatalyst to synthesize synthons in the food and pharmaceutical industries. Graphical abstract (Source: Journal of Molecular Catalysis B: Enzymatic)
Source: Journal of Molecular Catalysis B: Enzymatic - July 21, 2016 Category: Biochemistry Source Type: research

A novel member of family 30 glycoside hydrolase subfamily 8 glucuronoxylan endo- β-1,4-xylanase (CtXynGH30) from Clostridium thermocellum orchestrates catalysis on arabinose decorated xylans
Publication date: July 2016 Source:Journal of Molecular Catalysis B: Enzymatic, Volume 129 Author(s): Anil Kumar Verma, Arun Goyal A thermophilic enzyme, CtXynGH30 from Clostridium thermocellum was identified as glucuronoxylan endo-β-1,4-xylanase displayed activity extending to arabinose decorated xylans unlike other glucuronoxylan endo-β-1,4-xylanase from family 30 sub-family 8 of glycoside hydrolase. Modular CtXynGH30 comprises N-terminal catalytic module CtXyn30A and C-terminal carbohydrate binding module of family 6, (CtCBM6). The purified CtXynGH30 displayed a molecular mass of approximately, 60kDa. CtXynGH3...
Source: Journal of Molecular Catalysis B: Enzymatic - July 20, 2016 Category: Biochemistry Source Type: research

Enzymatic production of prebiotic fructo ‐oligosteviol glycosides
Publication date: September 2016 Source:Journal of Molecular Catalysis B: Enzymatic, Volume 131 Author(s): Sebastian C. Spohner, Peter Czermak Fructo-oligosaccharides are low-caloric sweeteners with 30–50% of the sweetness of sucrose. They are also used as functional food ingredients due to their prebiotic properties, i.e. they stimulate the growth and activity of lactobacilli and bifidobacteria in the digestive tract. Such compounds are normally extracted from chicory, but they can also be produced enzymatically from sucrose using fructosyltransferases. Steviol glycosides are naturally sweet constituents of Stev...
Source: Journal of Molecular Catalysis B: Enzymatic - July 20, 2016 Category: Biochemistry Source Type: research

Kinetic resolution of (R,S)- α-tetralol catalyzed by crosslinked Candida antarctica lipase B enzyme supported on mesocellular foam: A nanoscale enzyme reactor approach
Publication date: October 2016 Source:Journal of Molecular Catalysis B: Enzymatic, Volume 132 Author(s): Manoj P. Kamble, Somnath D. Shinde, Ganapati D. Yadav Nanoscale enzyme reactors (NERs) of Candida. antarctica lipase B (CALB) were prepared by enzyme adsorption on to mesoporous microcellular foam (MCF) followed by enzyme crosslinking within the pores. NERs effectively prevent enzyme leaching and consequently improve thermal stability. MCF has a unique pore structure that is composed of spherical 40nm sized mesocellular pores connected by 5–20nm sized mesoporous windows. These smaller connecting pores preven...
Source: Journal of Molecular Catalysis B: Enzymatic - July 20, 2016 Category: Biochemistry Source Type: research

Enzymatic reduction of α-substituted ketones with concomitant dynamic kinetic resolution
Publication date: Available online 18 July 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Ronald L. Hanson, Zhiwei Guo, Francisco González-Bobes, Michaël D.B. Fenster, Animesh Goswami Racemic α-substituted ketones were converted to the corresponding chiral alcohols with high diastereo- and enantioselectivities using enzymatic reduction with concomitant dynamic kinetic resolution. Reductions of N-protected α-amino ketones by microorganisms and commercial enzymes provided N-protected α-amino alcohols. Choice of buffer was found to be a crucial factor for the successful reduction and sim...
Source: Journal of Molecular Catalysis B: Enzymatic - July 18, 2016 Category: Biochemistry Source Type: research

Silanized Maghemite for Cross-linked Enzyme Aggregates of Recombinant Xylanase from Trichoderma reesei
Publication date: Available online 13 July 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Shalyda Md Shaarani, Jamaliah Md Jahim, Roshanida A. Rahman, Ani Idris, Abdul Munir Abdul Murad, Rosli Md Illias Numerous state-of-the-art technologies and new types of carriers have been developed recently to improve enzyme immobilization. Cross-linked enzyme aggregate (CLEA) technology is a lucrative prospect, as several robust biocatalysts have been generated using this simple method of carrier-free immobilization with the possibility of using semipurified enzyme. However, the low lysine content ...
Source: Journal of Molecular Catalysis B: Enzymatic - July 14, 2016 Category: Biochemistry Source Type: research

One-pot stereoselective synthesis of chiral 1, 3-oxathiolane by Trichosporon laibachii lipase: Optimization by response surface methodology integrated a desirability function approach
Publication date: Available online 14 July 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Yuanyuan Zhang, Xin Gao, Caiyun Wang, Zhenkun Zheng, Lulu Wang, Junhong Liu The asymmetric synthesis of chiral 1,3-oxathiolan-5-ones has attracted a great deal of attention owing to their broad biological activities and importance as intermediates for a range of useful pharmaceuticals. However, the enantiomeric purity of desired enantiomer was moderate while maintaining high yield. Here, high enantiomerically pure chiral 1,3-oxathiolane intermediate was synthesized by cyclization-acetylation reactio...
Source: Journal of Molecular Catalysis B: Enzymatic - July 14, 2016 Category: Biochemistry Source Type: research