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.

A Thermotolerant Endo-1,4-β-Mannanase From Trichoderma virens UKM1: Cloning, Recombinant Expression and Characterization
Publication date: Available online 11 January 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Sin Yee Chai, Farah Diba Abu Bakar, Nor Muhammad Mahadi, Abdul Munir Abdul Murad A gene encoding a thermotolerant endo-1,4-β-mannanase belonging to glycosyl hydrolase family 5 (GH5) was isolated from the fungal strain Trichoderma virens UKM1 (manTV). The aim of this work was to heterologously express and characterize manTV for subsequent applications. The 1,329bp β-mannanase gene was cloned and expressed in Pichia pastoris X33 yeast cells, and the recombinant mannanase (rMANTV) was expressed as a H...
Source: Journal of Molecular Catalysis B: Enzymatic - January 12, 2016 Category: Biochemistry Source Type: research

Lipase Candida sp. 99-125Coupled with β-cyclodextrin as additive synthesized the human milk fat substitutes
Publication date: Available online 24 December 2015 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Xin Zhang, Kaili Nie, Yongli Zheng, Fang Wang, Li Deng, Tianwei Tan Lipids with specific distribution of fatty acids could benefit people in various aspects. Structured lipids rich in palmitic acid at the sn-2 position and oleic acid at the sn-1,3 positions are a mimic of human milk fat, which has been used as human milk fat substitute (HMFS). The aim of this work was to optimize the production of HMFS from blends of lard and oleic acid by applying an improved enzymatic synthesis. A cheap lipase...
Source: Journal of Molecular Catalysis B: Enzymatic - December 25, 2015 Category: Biochemistry Source Type: research

Further insight into the pH effect on the catalysis of mushroom tyrosinase
Publication date: Available online 22 December 2015 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Miguel Angel Maria-Solano, Carmen Vanessa Ortiz-Ruiz, Jose Luis Muñoz-Muñoz, Jose Antonio Teruel-Puche, Jose Berna, Pedro Antonio Garcia-Ruiz, Francisco Garcia-Canovas The pH has a great physiological effect on the catalysis of tyrosinase because protons can act as competitive-type inhibitors. In this work, a reaction mechanism is proposed whereby only the protonation of the free forms E m (met-tyrosinase) and E ox (oxy-tyrosinase) has a significant kinetic effect. The pKa value calculated f...
Source: Journal of Molecular Catalysis B: Enzymatic - December 23, 2015 Category: Biochemistry Source Type: research

Partial purification and characterization of L-asparaginase from an endophytic Talaromyces pinophilus isolated from the rhizomes of Curcuma amada
Publication date: Available online 21 December 2015 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Prajna Rao Krishnapura, Prasanna D. Belur L-asparaginase is a commercially significant enzyme. There exists a demand for a broad variety of microbial L-asparaginases with characteristics compatible with its different applications. Endophytic microorganisms, in particular are emerging as potential sources of L-asparaginases. The current work involves partial purification and characterization of L-asparaginase from Talaromyces pinophilus, an endophytic fungus isolated from the rhizomes of Curcuma amada. M...
Source: Journal of Molecular Catalysis B: Enzymatic - December 22, 2015 Category: Biochemistry Source Type: research

Selective laccase-catalyzed dimerization of phenolic compounds derived from lignin: Towards original symmetrical bio-based (bis) aromatic monomers
Publication date: Available online 21 December 2015 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Audery Llevot, Etienne Grau, Stéphane Carlotti, Stéphane Grelier, Henri Cramail A laccase-catalyzed process was developed to prepare, selectively, in high yield, dimers of lignin-based phenolic compounds without any purification. The influence of experimental parameters such as laccase loading, nature of solvent and the presence of oxygen on the conversion of vanillin was investigated. After the dimerization, the product obtained as a precipitate is filtered off and the solution containing the e...
Source: Journal of Molecular Catalysis B: Enzymatic - December 22, 2015 Category: Biochemistry Source Type: research

A combined temperature-pH study of urease kinetics. Assigning pKa values to ionizable groups of the active site involved in the catalytic reaction
Publication date: February 2016 Source:Journal of Molecular Catalysis B: Enzymatic, Volume 124 Author(s): Barbara Krajewska A combined temperature-pH study of urease kinetics was performed with the primary objective to assign the observed pK a values to the ionizable groups of the enzyme active site involved in the reaction. This was done in view of the fact that the identity of the groups detected by pH studies reported in the literature has never been conclusively resolved. Accordingly, herein the urease kinetic parameters KM and v max were measured at eight pHs between 5.0 and 8.3 in noninteracting biological buf...
Source: Journal of Molecular Catalysis B: Enzymatic - December 19, 2015 Category: Biochemistry Source Type: research

Asymmetric Morita–Baylis–Hillman reaction catalyzed by pepsin
Publication date: February 2016 Source:Journal of Molecular Catalysis B: Enzymatic, Volume 124 Author(s): Jing-Wen Xue, Jian Song, Ian C.K. Manion, Yan-Hong He, Zhi Guan Pepsin from porcine gastric mucous shown catalytic promiscuity was first discovered to catalyze the Morita–Baylis–Hillman (MBH) reaction between aromatic aldehydes with 2-cyclohexen-1-one or 2-cyclopenten-1-one in a two-phase medium of phosphate buffer/cyclohexane in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO). The best results of the corresponding MBH products up to 77% yield and 38% ee were achieved. Graphical abstract (Sourc...
Source: Journal of Molecular Catalysis B: Enzymatic - December 19, 2015 Category: Biochemistry Source Type: research

Cloning with kinetic and thermodynamic insight of a novel hyperthermostable β-glucosidase from Thermotoga naphthophila RKU-10T with excellent glucose tolerance
Publication date: Available online 10 December 2015 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Fatima Akram, Ikram ul Haq, Mahmood Ali Khan, Zahid Hussain, Hamid Mukhtar, Kaleem Iqbal With a paradigm shift in industry, moving from natural fuels to alternative renewable resource utilization, the need of efficient thermostable cellulases are expected to increase in future. β-glucosidase, an essential member of cellulases that plays a critical role in cellulosic biomass degradation and in many biological processes. Therefore, a novel β-glucosidase gene encodes a protein (BglA) of 446 amino...
Source: Journal of Molecular Catalysis B: Enzymatic - December 11, 2015 Category: Biochemistry Source Type: research

IN SITU IMMOBILIZATION OF Candida antarctica B LIPASE IN POLYURETHANE FOAM SUPPORT
Publication date: Available online 7 December 2015 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Nadia Ligianara D. Nyari, Ilizandra A. Fernandes, Cindy E. Bustamante-Vargas, Clarisse Steffens, Débora de Oliveira, Jamile Zeni, Elisandra Rigo, Rogério M. Dallago Candida antarctica B (CALB) lipase was immobilized using polyurethane (PU) foam as support by confinement method. This can be a promising technique due to the low cost of the support, simple procedure of immobilization and the possibility of using the derivative as catalyst for the food industry reactions. CALB immobilization o...
Source: Journal of Molecular Catalysis B: Enzymatic - December 9, 2015 Category: Biochemistry Source Type: research

One-pot enzymatic reaction sequence for the syntheses of d-glyceraldehyde 3-phosphate and l-glycerol 3-phosphate
Publication date: Available online 8 December 2015 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Getachew S. Molla, Roland Wohlgemuth, Andreas Liese A one-pot enzymatic reaction sequence for the synthesis of optically pure d-glyceraldehyde 3-phosphate (d-GAP) and l-glycerol 3-phosphate (sn -G3P) was designed using fructose-bisphosphate aldolase from rabbit muscle (RAMA), sn -glycerol 3-phosphate dehydrogenase (sn -G3PDH) and formate dehydrogenase from Candida boidinii (FDH). The reaction sequence significantly improves the aldol cleavage of d-fructose 1,6-bisphosphate (d-F16BP) catalyzed by RAMA a...
Source: Journal of Molecular Catalysis B: Enzymatic - December 9, 2015 Category: Biochemistry Source Type: research

A functional role identified for conserved charged residues at the active site entrance of lipoxygenase with double specificity
In this study, we used the olive LOX1 with double specificity to investigate the implication of the charged residues R265, R268, and K283 in the orientation of the substrate into the active site. These residues are present in a conserved pattern around the entrance of the active site. Our results show that these residues are involved in the penetration of the substrate into the active site: this positive patch could capture the carboxylate end of the substrate, and then guide it into the active site. Due to its position on α2 helix, the residue K283 could have a more important role, its interaction with the substrate faci...
Source: Journal of Molecular Catalysis B: Enzymatic - December 6, 2015 Category: Biochemistry Source Type: research

Recyclable solid-phase biocatalyst with improved stability by sol–gel entrapment of β-d-galactosidase
Publication date: January 2016 Source:Journal of Molecular Catalysis B: Enzymatic, Volume 123 Author(s): Emese Biró, Daniel Budugan, Anamaria Todea, Francisc Péter, Szilvia Klébert, Tivadar Feczkó β-d-Galactosidase from Kluyveromyces lactis was for the first time immobilized by entrapment in hybrid organic-inorganic sol–gel materials with microporous structure, obtained from alkoxy silanes and alkyl substituted alkoxy silanes, in different combinations. The immobilization matrix was tailored by fine tuning of several parameters, such as: nature of alkyl group of silane precursors, molar ratio of sila...
Source: Journal of Molecular Catalysis B: Enzymatic - December 6, 2015 Category: Biochemistry Source Type: research

Evaluating the kinetics of the esterification of oleic acid with homo and heterogeneous catalysts using in-line real-time infrared spectroscopy and partial least squares calibration
Publication date: January 2016 Source:Journal of Molecular Catalysis B: Enzymatic, Volume 123 Author(s): Vinicius Kartnaller, Ivaldo I. Junior, Adriana V.A. de Souza, Ingrid C.R. Costa, Michelle J.C. Rezende, João F. Cajaiba da Silva, Rodrigo O.M.A. de Souza Biodiesel is a mixture of fatty acid alkyl esters with properties similar to petroleum-based diesel. Thus, biodiesel can be used as either a substitute for diesel fuel or, more commonly, in a fuel blend. Biodiesel production can be catalyzed with mineral acids or bases or enzymes. The use of real-time techniques for monitoring the reaction and evalua...
Source: Journal of Molecular Catalysis B: Enzymatic - December 6, 2015 Category: Biochemistry Source Type: research

Synthesis of pyrazine via chemoselective reduction of β-keto-α-oximino ester using baker’s yeast
Publication date: January 2016 Source:Journal of Molecular Catalysis B: Enzymatic, Volume 123 Author(s): Kilwoong Mo, Jin Hyeong Park, Soon Bang Kang, Youseung Kim, Yong Sup Lee, Jae Wook Lee, Gyochang Keum The synthesis of pyrazines by the baker’s yeast-mediated reaction of β-keto-α-oximino esters and amides is described. Baker’s yeast reduced oximes selectively over ketones of β-keto-α-oximino esters to give the corresponding β-keto-α-amino ester intermediates, which underwent spontaneous dimerization followed by air-induced aromatization to yield pyrazines. The chemoselective reduction of β-...
Source: Journal of Molecular Catalysis B: Enzymatic - December 6, 2015 Category: Biochemistry Source Type: research

Asymmetric Morita-Baylis-Hillman Reaction Catalyzed by Pepsin
Publication date: Available online 4 December 2015 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Jing-Wen Xue, Jian Song, Ian C.K. Manion, Yan-Hong He, Zhi Guan Pepsin from porcine gastric mucous shown catalytic promiscuity was first discovered to catalyze the Morita-Baylis-Hillman (MBH) reaction between aromatic aldehydes with 2-cyclohexen-1-one or 2-cyclopenten-1-one in a two-phase medium of phosphate buffer/cyclohexane in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO). The best results of the corresponding MBH products up to 77% yield and 38% ee were achieved. Graphical abstract (So...
Source: Journal of Molecular Catalysis B: Enzymatic - December 5, 2015 Category: Biochemistry Source Type: research