Optimum substrate size and specific anomer requirements for the reducing-end glycoside hydrolase di-N-acetylchitobiase.
Di-N-acetylchitobiase is a family 18 glycoside hydrolase that splits the reducing-end GlcNAc from chitooligosaccharides. The enzyme hydrolyzed only the alpha-anomer of five tested substrates, chitin di- through hexasaccharide. In all cases the glycosyl fragment retained its beta-configuration while the split monosaccharide was alpha-D-GlcNAc. Chitobiose was hydrolyzed less than half as fast as the other larger substrates. All four of them, tri- to hexasaccharide, reacted at the same rate. The biochemical behavior of di-N-acetylchitobiase indicates it has three subsites, -2, -1, +1, in which the reducing-end trimer of any sized chitooligosaccharide is bound. The +1 site is specific for an alpha-anomer.
Aronson
Nathan N
NN
Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688, USA. naronson@jaguar1.usouthal.edu
Halloran
Brian A
BA
D000118:Acetylglucosaminidase / Q000378:metabolism*; D000818:Animals; D002240:Carbohydrate Sequence; D002645:Chickens; D006801:Humans; D006868:Hydrolysis; D007700:Kinetics; D010084:Oxidation-Reduction; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity
D011994:Recombinant Proteins; D000118:Acetylglucosaminidase