SUBSTRATE SPECIFICITY OF D-GALACTOSE OXIDASE

The rate of oxidation of methyl ethers of D-galactose and 2-amino-2-deoxy-D-galactose, and of oligosaccharides and polysaccharides containing D-galactosyl residues having a free hydroxyl group at C-6, has been followed by various procedures that depend either upon the hydrogen peroxide or the aldehyde groups produced, or upon the unoxidized D-galactose residues remaining in the reaction mixture. Derivatives of D-galactose having substituents on the hydroxyl group at C-4 are not oxidized. 2-Amino-2-deoxy-D-galactose residues having glycosyl substituents at C-3 are not oxidized by the enzyme, and therefore, neither are chondroitin 4-sulfate nor dermatan sulfate. No completely satisfactory procedure was found for following the oxidation reaction to termination, which, in none of the cases studied, was 100% complete. © 1968.