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.

Hyperactivation of α-chymotrypsin by the Hofmeister effect
Publication date: Available online 19 March 2017 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Akihiro Endo, Takaaki Kurinomaru, Kentaro Shiraki The enzyme activity of α-chymotrypsin (ChT) has been known to increase with the addition of polyelectrolytes and amine compounds that combine with oppositely charged substrates. Enzyme hyperactivation is thought to occur by changing the electrostatic field around the enzyme, leading to favorable interactions between the enzyme and substrate. Inspired by the enzyme hyperactivation system, this paper focuses on inorganic salts as additives that specifically aff...
Source: Journal of Molecular Catalysis B: Enzymatic - March 19, 2017 Category: Biochemistry Source Type: research

Demasking kinetics of peptide bond cleavage for whey protein isolate hydrolysed by Bacillus licheniformis protease
Publication date: Available online 16 March 2017 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Mikhail M. Vorob’ev, Claire I. Butré, Stefano Sforza, Peter A. Wierenga, Harry Gruppen During enzymatic hydrolysis of proteins, some cleavage sites will be accessible in the intact protein. Others may only become accessible after demasking of the cleavage site, i.e. after cleavage of other bonds in the protein. Studies on demasking so far have used data of the release of few peptides in a hydrolysate. To obtain a more complete understanding of the hydrolysis kinetics and to validate the demasking model, ...
Source: Journal of Molecular Catalysis B: Enzymatic - March 16, 2017 Category: Biochemistry Source Type: research

Asymmetric reductive resolution of racemic sulfoxides by recombinant methionine sulfoxide reductase from a pseudomonas monteilii strain
In this study, the methionine sulfoxide reductase A from a pseudomonas monteilii strain (pmMsrA) was reported to synthesize optically active sulfoxides (R)-1a-4a, through asymmetric biocatalytic reductive resolution. Several biotransformation parameters including the reaction time, cell density, and substrate concentration were optimized. Moreover, Substrate scope of pmMsrA catalyzed asymmetric reductive resolution was investigated, which gave chiral (R)-1a-4a with 61%-97% ee. (Source: Journal of Molecular Catalysis B: Enzymatic)
Source: Journal of Molecular Catalysis B: Enzymatic - March 11, 2017 Category: Biochemistry Source Type: research

Insight into the mechanism behind the activation phenomenon of lipase from Thermus thermophilus HB8 in polar organic solvents
Publication date: Available online 8 March 2017 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Hao Cao, Kaili Nie, Haijun Xu, Xin Xiong, Rumen Krastev, Fang Wang, Tianwei Tan, Luo Liu A thermophilic lipase from Thermus thermophilus (lipaseTt) was heterologously overexpressed in Escherichia coli BL21(DE3). The tolerance of (lipaseTt) towards polar organic solvents and the associated activation phenomena were investigated. The catalytic efficiency (Kcat/KM) of lipaseTt in 56% DMSO was up to 25.64 times higher than that in phosphate buffer. Molecular dynamic (MD) simulations were carried out to invest...
Source: Journal of Molecular Catalysis B: Enzymatic - March 8, 2017 Category: Biochemistry Source Type: research

Computational insights into the oxidation of mono- and 1,4 disubstituted arenes by the Toluene Dioxygenase enzymatic complex
Publication date: Available online 8 March 2017 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Ma. Agustina Vila, Diego Umpiérrez, Gustavo Seoane, Sonia Rodríguez, Ignacio Carrera, Nicolás Veiga Toluene Dioxygenase (TDO) enzymatic complex has been widely used for preparation of enantiopure cis-cyclohexadienediols for synthetic applications. Along the last 30 years, a variety of mono- and di-substituted arenes have been studied as substrates for this enzyme, and some interesting observations have been reported regarding the yield and selectivity of the biotransformation. Nevertheless, none of them ...
Source: Journal of Molecular Catalysis B: Enzymatic - March 8, 2017 Category: Biochemistry Source Type: research

Lipase mediated resolution of cis- and trans-linalool oxide (pyranoid)
Publication date: Available online 9 March 2017 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Stefano Serra, Davide De Simeis, Elisabetta Brenna The four isomeric forms of the flavour linalool oxide (pyranoid) were synthesized starting from the inexpensive monoterpene terpinolene. The key steps of the process include mCPBA epoxidation of the starting diene, alumina-catalysed rearrangement of the obtained diepoxide and the diastereoselective reduction of the ketone 2,2,6-trimethyl-6-vinyldihydro-2H-pyran-3(4H)-one. The resulting racemic cis- and trans-linalool oxides were resolved through an enzyme-medi...
Source: Journal of Molecular Catalysis B: Enzymatic - March 8, 2017 Category: Biochemistry Source Type: research

Three New Analogues of Androgenic Drug Mesterolone through Biotransformation with Cunninghamella blakseleeana
Publication date: Available online 2 March 2017 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Malik Shoaib Ahmad, Rabia Farooq, Nusrat Hussain, Atia-tul-Wahab, Atta-ur-Rahman, M.Iqbal Choudhary Three new metabolites were obtained on incubation of androgenic steroid mesterolone (1) with Cunninghamella blakesleeana. These metabolites were identified as 1α-methyl-11β,14α,17β-trihydroxy-5α-androstan-3-one (2), 1α-methyl-7β,17β-dihydroxy-5α-androstan-3-one (3), and 1α-methyl,17β-hydroxy-5α-androstan-3,7-dione (4). During this study, hydroxylation at C-11, C-14, and C-15, and oxidation at C-7 ...
Source: Journal of Molecular Catalysis B: Enzymatic - March 2, 2017 Category: Biochemistry Source Type: research

Improved ethyl butyrate synthesis catalyzed by an immobilized recombinant Rhizopus oryzae lipase: A comprehensive statistical study by production, reaction rate and yield analysis
Publication date: Available online 22 February 2017 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Marina Guillén, M. Dolors Benaiges, Francisco Valero The combined effect of the substrates on the ethyl butyrate (EB) synthesis (pineapple flavour) by a recombinant lipase from Rhizopus oryzae (rROL) immobilized in Octadecyl-Sepabeads has been studied. The initial concentration of butyric acid (BA) and the molar ratio butyric acid:ethanol (BA:ET) were selected as the key parameters to describe this combined effect. The study was focused on the maximization of the flavour production by applying a central c...
Source: Journal of Molecular Catalysis B: Enzymatic - March 1, 2017 Category: Biochemistry Source Type: research

Engineering of N-Acetyl-L-glutamate kinase from Corynebacterium glutamicum toward improved catalytic efficiency and thermostability
Publication date: Available online 20 February 2017 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Jingjing Zhang, Meijuan Xu, Xian Zhang, Taowei Yang, Zhenghong Xu, Zhiming Rao N-Acetyl-L-glutamate kinase (NAGK) is a key enzyme in the synthesis of L-arginine. Although, solving the problem of L-arginine feedback inhibition for NAGK is a vital way for improving L-arginine production, an equally important mechanism is improving catalytic activity and thermostability of NAGK. We successfully improved thermostability and catalytic efficiency of NAGK from Corynebacterium glutamicum (CgNAGK) by site-satura...
Source: Journal of Molecular Catalysis B: Enzymatic - February 27, 2017 Category: Biochemistry Source Type: research

Endophytic microorganisms: A source of potentially useful biocatalysts
Publication date: Available online 27 February 2017 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Paula Rodriguez, David Gonzalez, Sonia Rodríguez Giordano One of the major challenges in biocatalysis is the discovery or development of novel biocatalysts suitable for different applications. Within the last decades, directed evolution has emerged as a powerful tool for generating diversity and has allowed the development of biocatalysts with the desired properties. An alternative way to increase diversity among biocatalysts is to further explore nature on the search for novel activities or broader subst...
Source: Journal of Molecular Catalysis B: Enzymatic - February 27, 2017 Category: Biochemistry Source Type: research

Biochemical characterization of a novel feruloyl esterase from Penicillium piceum and its application in biomass bioconversion
Publication date: Available online 24 February 2017 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Le Gao, Min Wang, Shulin Chen, Dongyuan Zhang A putative feruloyl esterase (FAE) was successfully cloned from the genomic DNA of Penicillium piceum and expressed in E. coli. The deduced internal amino acid sequence of the novel FAE was found to have 56% sequence identity with FAE from Aspergillius flavus and was designated as PpFAE. PpFAE contained the conserved region flanking the characteristic G-X-S-X-G motif of a serine esterase, suggesting a FAE function for the protein. Substrate specificity profili...
Source: Journal of Molecular Catalysis B: Enzymatic - February 24, 2017 Category: Biochemistry Source Type: research

Improved ethyl butyrate synthesis catalysed by an immobilized recombinant Rhizopus oryzae lipase: A comprehensive statistical study by production, reaction rate and yield analysis
Publication date: Available online 22 February 2017 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Marina Guillén, M. Dolors Benaiges, Francisco Valero The combined effect of the substrates on the ethyl butyrate (EB) synthesis (pineapple flavour) by a recombinant lipase from Rhizopus oryzae (rROL) immobilized in Octadecyl-Sepabeads has been studied. The initial concentration of butyric acid (BA) and the molar ratio butyric acid:ethanol (BA:ET) were selected as the key parameters to describe this combined effect. The study was focused on the maximization of the flavour production by applying a central c...
Source: Journal of Molecular Catalysis B: Enzymatic - February 21, 2017 Category: Biochemistry Source Type: research

Kinetic, thermodynamic, optimization and reusability studies for the enzymatic synthesis of a saturated wax ester
In this study, a second-order reversible reaction kinetic model was proposed in order to estimate apparent kinetic constants and good agreement with experimental data was observed (0.9430≤R2 ≤0.9938). The reaction was found to be a spontaneous and endothermic process. The biocatalyst prepared with initial protein loading of 115mg/g of support (immobilized protein concentration of 108.7±3.1mg/g) yielded the highest initial reaction rate (113.5mM/min of reaction), then selected for subsequent tests. The reaction in heptane medium required a slight excess of cetyl alcohol (molar ratio acid:alcohol of 1:1.25) and 7.5% m/m...
Source: Journal of Molecular Catalysis B: Enzymatic - February 20, 2017 Category: Biochemistry Source Type: research

Engineering of N-Acetyl-L-glutamate kinase from Corynebacterium glutamicum towards improved catalytic efficiency and thermostability
Publication date: Available online 20 February 2017 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Jingjing Zhang, Meijuan Xu, Xian Zhang, Taowei Yang, Zhenghong Xu, Zhiming Rao N-Acetyl-L-glutamate kinase (NAGK) is a key enzyme in the synthesis of L-arginine. Although solving the problem of L-arginine feedback inhibition for NAGK is a vital way for improving L-arginine production, an equally important mechanism is improving catalytic activity and thermostability of NAGK. We successfully improved thermostability and catalytic efficiency of NAGK from Corynebacterium glutamicum (CgNAGK) by site-saturat...
Source: Journal of Molecular Catalysis B: Enzymatic - February 20, 2017 Category: Biochemistry Source Type: research

Regioselective hydroxylation of lathyrane diterpenoids biocatalyzed by microorganisms and its application in integrated synthesis
Publication date: Available online 16 February 2017 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Yiqing Wu, Chengle Yin, Yue Cao, Xin Liu, Jinxiang Yu, Jian Zhang, Boyang Yu, Zhihong Cheng The regioselective oxidation of three lathyrane diterpenoids (lathyrol, 1; 7β-hydroxylathyrol, 2; and Euphorbia factor L3, 3) catalyzed by the fungi Mortierella ramanniana CGMCC 3.03413, Mucor circinelloides CICC 40242, and the actinomycete Nocardia iowensis sp. nov. NRRL 5646 was investigated. Ten new metabolites (4–13) including two unprecedented cyclopropane-rearranged products (4 and 5) have been obtaine...
Source: Journal of Molecular Catalysis B: Enzymatic - February 16, 2017 Category: Biochemistry Source Type: research