Kinetic Properties of Galactose Oxidase from Gibberella fujikuroi

Abstract

The kinetic properties of galactose oxidase of Gibberella fujikuroi were investigated. The enzyme oxidized D-galactose, 2-substituted D-galactoses, 2-epimer D-talose, and D-galactose-containing oligosaccharides, but not other saccharides. The enzyme was highly specific for molecular oxygen as an electron acceptor. The enzyme gave a nonlinear Lineweaver-Burk plot when the oxidation rate at a variety of galactose concentrations was investigated. The data were well explained by the assumption that the enzyme has two binding sites for galactose. K1 and K2, which are the dissociation constants for the first and second bindings of galactose to the enzyme, were calculated to be 1.3 mM and 42 mM, respectively. The enzyme was mixedly inhibited by d-galacturonic acid. © 1984, Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.