title: Characterization of a GH family 3 β-glycoside hydrolase from Chrysosporium lucknowense and its application to the hydrolysis of β-glucan and xylan.
abstract: The Bxl5-gene encoding a GH3 glycoside hydrolase of Chrysosporium lucknowense C1 was successfully cloned, the homologous recombinant product was secreted, purified and characterized. Bxl5 (120 ± 5 kDa) was able to hydrolyze low molecular weight substrates and polysaccharides containing β-glucosidic as well as β-xylosidic residues. The K(m) and V(max)/E values were found to be 0.3mM and 88 s(-1) on p-nitrophenyl-β-d-glucopyranoside (PNPG), and 13.5mM and 1.8s(-1) on p-nitrophenyl-β-d-xylopyranoside (PNPX). Optimal pH and temperature for Bxl5 were 4.6 and 75°C for the PNPG hydrolysis, and 5.0-5.5 and 70°C for PNPX hydrolysis. The enzyme was quite stable when incubated at elevated temperatures up to 65°C. Bxl5 hydrolyzes polymeric β-glucans by the exo-mechanism allowing their complete conversion to d-glucose and is effective for xylan hydrolysis in combination with endo-acting xylan-degrading enzymes. The enzyme seems to be a very promising for bioconversion purposes.
authors.affiliation: Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow, Russia. gsdotsenko@gmail.com
authors.forename: G S
authors.initials: GS
authors.lastname: Dotsenko
authors.forename: O A
authors.initials: OA
authors.lastname: Sinitsyna
authors.forename: S W A
authors.initials: SW
authors.lastname: Hinz
authors.forename: J
authors.initials: J
authors.lastname: Wery
authors.forename: A P
authors.initials: AP
authors.lastname: Sinitsyn
mesh_terms: D002912:Chrysosporium / Q000187:drug effects / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004795:Enzyme Stability / Q000187:drug effects; D005110:Extracellular Space / Q000187:drug effects / Q000201:enzymology; D006026:Glycoside Hydrolases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D001467:Hordeum / Q000187:drug effects / Q000378:metabolism; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D006868:Hydrolysis / Q000187:drug effects; D007700:Kinetics; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity / Q000187:drug effects; D013696:Temperature; D014990:Xylans / Q000378:metabolism*; D047071:beta-Glucans / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D014990:Xylans; D047071:beta-Glucans; D006026:Glycoside Hydrolases