title: Beta-glucosidase, exo-beta-glucanase and pyridoxine transglucosylase activities of rice BGlu1.
abstract: The bglu1 cDNA for a beta-glucosidase cloned from rice (Oryza sativa L.) seedlings was expressed as a soluble and active protein in Escherichia coli and designated BGlu1. This enzyme hydrolysed beta-1,4-linked oligosaccharides with increasing catalytic efficiency (kcat/Km) values as the DP (degree of polymerization) increased from 2 to 6. In contrast, hydrolysis of beta-1,3-linked oligosaccharides decreased from DP 2 to 3, and polymers with a DP greater than 3 were not hydrolysed. The enzyme also hydrolysed p -nitrophenyl beta-D-glycosides and some natural glucosides but with lower catalytic efficiency than beta-linked oligosaccharides. Pyridoxine 5'-O-beta-D-glucoside was the most efficiently hydrolysed natural glycoside tested. BGlu1 also had high transglucosylation activity towards pyridoxine, producing pyridoxine 5'-O-beta-D-glucopyranoside in the presence of the glucose donor p-nitrophenyl beta-D-glucoside.
authors.affiliation: Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.
authors.forename: Rodjana
authors.initials: R
authors.lastname: Opassiri
authors.forename: Yanling
authors.initials: Y
authors.lastname: Hua
authors.forename: Onnop
authors.initials: O
authors.lastname: Wara-Aswapati
authors.forename: Takashi
authors.initials: T
authors.lastname: Akiyama
authors.forename: Jisnuson
authors.initials: J
authors.lastname: Svasti
authors.forename: Asim
authors.initials: A
authors.lastname: Esen
authors.forename: James R
authors.initials: JR
authors.lastname: Ketudat Cairns
mesh_terms: D000595:Amino Acid Sequence; D002236:Carbohydrate Conformation; D002851:Chromatography, High Pressure Liquid; D018076:DNA, Complementary / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D044643:Glucan 1,4-beta-Glucosidase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D005960:Glucosides / Q000378:metabolism; D005964:Glucosyltransferases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006027:Glycosides / Q000378:metabolism; D001467:Hordeum / Q000201:enzymology; D006868:Hydrolysis; D007700:Kinetics; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism; D012275:Oryza / Q000201:enzymology* / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011736:Pyridoxine / Q000031:analogs & derivatives* / Q000378:metabolism; D036226:Seedlings / Q000201:enzymology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D013379:Substrate Specificity; D001617:beta-Glucosidase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D018076:DNA, Complementary; D018744:DNA, Plant; D005960:Glucosides; D006027:Glycosides; D009844:Oligosaccharides; D010940:Plant Proteins; C025193:4-nitrophenyl beta-D-glucoside; C022945:5'-O-(glucopyranosyl)pyridoxine; D005964:Glucosyltransferases; D001617:beta-Glucosidase; D044643:Glucan 1,4-beta-Glucosidase; D011736:Pyridoxine