title: Modulation of substrate preference of thermus maltogenic amylase by mutation of the residues at the interface of a dimer.
abstract: To elucidate the relationship between the substrate size and geometric shape of the catalytic site of Thermus maltogenic amylase, Gly50, Asp109, and Val431, located at the interface of the dimer, were replaced with bulky amino acids. The k(cat)/K(m) value of the mutant for amylose increased significantly, whereas that for amylopectin decreased as compared to that of the wild-type enzyme. Thus, the substituted bulky amino acid residues modified the shape of the catalytic site, such that the ability of the enzyme to distinguish between small and large molecules like amylose and amylopectin was enhanced.
authors.affiliation: Department of Food Science and Agricultural Chemistry, McGill University, Canada.
authors.forename: Sung-Hoon
authors.initials: SH
authors.lastname: Park
authors.forename: Hee-Kwon
authors.initials: HK
authors.lastname: Kang
authors.forename: Jae-Hoon
authors.initials: JH
authors.lastname: Shim
authors.forename: Eui-Jeon
authors.initials: EJ
authors.lastname: Woo
authors.forename: Jung-Sun
authors.initials: JS
authors.lastname: Hong
authors.forename: Jung-Wan
authors.initials: JW
authors.lastname: Kim
authors.forename: Byung-Ha
authors.initials: BH
authors.lastname: Oh
authors.forename: Byong Hoon
authors.initials: BH
authors.lastname: Lee
authors.forename: Hyunju
authors.initials: H
authors.lastname: Cha
authors.forename: Kwan-Hwa
authors.initials: KH
authors.lastname: Park
mesh_terms: D000596:Amino Acids; D000681:Amylases / Q000235:genetics / Q000378:metabolism*; D000687:Amylopectin / Q000378:metabolism; D000688:Amylose / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics; D019281:Dimerization; D007700:Kinetics; D009154:Mutation; D013379:Substrate Specificity / Q000235:genetics*; D013824:Thermus / Q000201:enzymology*
chemical_list: D000596:Amino Acids; D000688:Amylose; D000687:Amylopectin; D000681:Amylases