By a News Reporter-Staff News Editor at Life Science Weekly -- Current study results on Enzymes and Coenzymes have been published. According to news originating from Beijing, People's Republic of China, by NewsRx correspondents, research stated, "Functional screening of a metagenomic library constructed with DNA extracted from the rumen contents of a grass/hay-fed dairy cow identified a protein, beta-glucosidase/beta-xylosidase/alpha-arabinosidase gene (Bgxa1), with high levels of beta-glucosidase activity. Purified Bgxa1 was highly active against p-nitrophenyl-beta-d-glucopyranoside (pNPG), cellobiose, p-nitrophenyl-beta-d-xylopyranoside (pNPX) and p-nitrophenyl-alpha-d-arabinofuranoside (pNPAf), suggesting it is a multifunctional beta-glucosidase/beta-xylosidase/alpha-arabinosidase."
Our news journalists obtained a quote from the research from Feed Research Institute, "Kinetic analysis of the protein indicated that Bgxa1 has the greatest catalytic activity against pNPG followed by pNPAf and pNPX, respectively. The catalytic efficiency of beta-glucosidase activity was 100x greater than beta-xylosidase or alpha-arabinosidase. The pH and temperature optima for the hydrolysis of selected substrates also differed considerably with optima of pH 6.0/45 A degrees C and pH 8.5/40 A degrees C for pNPG and pNPX, respectively. The pH dependence of pNPAf hydrolysis displayed a bimodal distribution with maxima at both pH 6.5 and pH 8.5. The enzyme exhibited substrate-dependent responses to changes in ionic strength. Bgxa1 was highly stable over a broad pH range retaining at least 70 % of its relative catalytic activity from pH 5.0-10.0 with pNPG as a substrate. Homology modelling was employed to probe the structural basis of the unique specificity of Bgxa1 and revealed the deletion of the PA14 domain and insertions in loops adjacent to the active site. This domain has been found to be an important determinant in the substrate specificity of proteins related to Bgxa1. It is postulated that these indels are, in part, responsible for the multifunctional activity of Bgxa1. Bgxa1 acted synergistically with endoxylanase (Xyn10N18) when incubated with birchwood xylan, increasing the release of reducing sugars by 168 % as compared to Xyn10N18 alone. Examination of Bgxa1 and Xyn10N18 synergy with a cellulase for the saccharification of alkali-treated straw revealed that synergism among the three enzymes enhanced sugar release by 180 % as compared to cellulase alone."
According to the news editors, the research concluded: "Our results suggest that Bgxa1 has a number of properties that make it an interesting candidate for the saccharification of lignocellulosic material."
For more information on this research see: Biochemical and kinetic characterization of the multifunctional beta-glucosidase/beta-xylosidase/alpha-arabinosidase, Bgxa1. Applied Microbiology and Biotechnology, 2014;98(7):3003-3012. Applied Microbiology and Biotechnology can be contacted at: Springer, 233 Spring St, New York, NY 10013, USA. (Springer - www.springer.com; Applied Microbiology and Biotechnology - www.springerlink.com/content/0175-7598/)
The news correspondents report that additional information may be obtained from R.J. Gruninger, Chinese Academy Agr Sci, Feed Res Inst, Beijing 100193, People's Republic of China. Additional authors for this research include X. Gong, R.J. Forster and T.A. McAllister (see also Enzymes and Coenzymes).
Keywords for this news article include: Asia, Beijing, Chemistry, Cellulases, Biochemical, beta-Glucosidase, Glycoside Hydrolases, Enzymes and Coenzymes, People's Republic of China
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