title: Purification and characterization of Acremonium implicatum alpha-glucosidase having regioselectivity for alpha-1,3-glucosidic linkage.
abstract: alpha-Glucosidase with a high regioselectivity for alpha-1,3-glucosidic linkages for hydrolysis and transglucosylation was purified from culture broth of Acremonium implicatum. The enzyme was a tetrameric protein (M.W. 440,000), of which the monomer (M.W. 103,000; monomeric structure was expected from cDNA sequence) was composed of two polypeptides (M.W. 51,000 and 60,000) formed possibly by posttranslational proteolysis. Nigerose and maltose were hydrolyzed by the enzyme rapidly, but slowly for kojibiose. The k(0)/K(m) value for nigerose was 2.5-fold higher than that of maltose. Isomaltose was cleaved slightly, and sucrose was not. Maltotriose, maltotetraose, p-nitrophenyl alpha-maltoside and soluble starch were good substrates. The enzyme showed high affinity for maltooligosaccharides and p-nitrophenyl alpha-maltoside. The enzyme had the alpha-1,3- and alpha-1,4-glucosyl transfer activities to synthesize oligosaccharides, but no ability to form alpha-1,2- and alpha-1,6-glucosidic linkages. Ability for the formation of alpha-1,3-glucosidic linkage was two to three times higher than that for alpha-1,4-glucosidic linkage. Eight kinds of transglucosylation products were synthesized from maltose, in which 3(2)-O-alpha-nigerosyl-maltose and 3(2)-O-alpha-maltosyl-maltose were novel saccharides.
authors.affiliation: Nihon Shokuhin Kako Co. Ltd., 30 Tajima Fuji Shizuoka 417-8530, Japan. takeshi.yamamoto@nisshoku.co.jp
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Takehiro
authors.initials: T
authors.lastname: Unno
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Mikio
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Masayuki
authors.initials: M
authors.lastname: Okuyama
authors.forename: Haruhide
authors.initials: H
authors.lastname: Mori
authors.forename: Seiya
authors.initials: S
authors.lastname: Chiba
authors.forename: Atsuo
authors.initials: A
authors.lastname: Kimura
mesh_terms: D000164:Acremonium / Q000201:enzymology*; D002236:Carbohydrate Conformation; D004187:Disaccharides / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry / Q000302:isolation & purification; D007700:Kinetics; D008320:Maltose / Q000378:metabolism; D009844:Oligosaccharides / Q000096:biosynthesis; D021122:Protein Subunits; D013379:Substrate Specificity; D000520:alpha-Glucosidases / Q000737:chemistry* / Q000302:isolation & purification*
chemical_list: D004187:Disaccharides; D005656:Fungal Proteins; D009844:Oligosaccharides; D021122:Protein Subunits; C014637:laminaribiose; D008320:Maltose; D000520:alpha-Glucosidases