title: Purification and characterization of thermostable alpha-galactosidase from Ganoderma lucidum.
abstract: Alpha-galactosidase was purified from a fresh fruiting body of Ganoderma lucidum by precipitation with ammonium sulfate and column chromatographies with DEAE-Sephadex and Con A-Sepharose. The purified enzyme was homogeneous on polyacrylamide gel electrophoresis. Its N-terminal amino acid sequence was similar to that of Mortierella vinacea alpha-galactosidase. The molecular mass of the enzyme was about 56 kDa by SDS-polyacrylamide gel electrophoresis, and about 249 kDa by gel filtration column chromatography. The optimum pH and temperature were 6.0 and 70 degrees C, respectively. The enzyme was fully stable to heating at 70 degrees C for 30 min. It hydrolyzed p-nitrophenyl-alpha-D-galactopyranoside (Km=0.4 mM) but hydrolyzed little o-nitrophenyl-alpha-D-galactopyranoside. It also hydrolyzed melibiose, raffinose, and stachyose. The enzyme catalyzed the transgalactosylation reaction which synthesized melibiose. The product was confirmed by various analyses.
authors.affiliation: Department of Chemistry, Faculty of Science, Chiang Mai University, Thailand. thidach@yahoo.com
authors.forename: Thida
authors.initials: T
authors.lastname: Sripuan
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Aoki
authors.forename: Kenji
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Dararat
authors.initials: D
authors.lastname: Tongkao
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Kumagai
mesh_terms: D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D006031:Glycosylation; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000494:pharmacology; D008970:Molecular Weight; D020940:Reishi / Q000201:enzymology* / Q000254:growth & development; D013379:Substrate Specificity; D013696:Temperature; D000519:alpha-Galactosidase / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*
chemical_list: D008670:Metals; D000519:alpha-Galactosidase