Aronson Nathan N, Halloran Brian A
Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688, USA.
Biosci Biotechnol Biochem. 2006 Jun;70(6):1537-41. doi: 10.1271/bbb.60183.
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.
