Enzymatic synthesis of p-nitrophenyl 3(5)-O-beta-N-acetylglucosaminyl-alpha-maltopentaoside by lysozyme; a novel substrate for human amylase assay.

Transglycosylation from di-N-acetylchitobiose to the 3-position at the nonreducing end glucosyl group of p-nitrophenyl alpha-maltopentaoside was regioselectively induced through the use of hen egg-white lysozyme. The enzyme formed p-nitrophenyl 3(5)-O-beta-N-acetylglucosaminyl-alpha-maltopentaoside (5% of the enzyme-catalyzed net decrease of p-nitrophenyl alpha-maltopentaoside) from di-N-acetylchitobiose as a donor and p-nitrophenyl alpha-maltopentaoside as an acceptor. The rate of the transglycosylation depended on the concentration of substrate, the temperature and the pH. The hydrolytic actions of human pancreatic and salivary alpha-amylase on this derivative were examined. The maltopentaoside derivative was shown to be useful as a substrate for alpha-amylase assay through a coupled reaction involving alpha-D-glucosidase and glucoamylase.