Novel transglucosylating reaction of sucrose phosphorylase to carboxylic compounds such as benzoic acid.

We examined the synthesis of benzoyl glucoside using the transglucosylation reaction of sucrose phosphorylase. Sucrose phosphorylase from Streptococcus mutans showed marked transglucosylating activity, particularly under acidic conditions. On the other hand, sucrose phosphorylase from Leuconostoc mesenteroides showed very weak transglucosylating activity. Three main products were detected from the reaction mixture using benzoic acid as an acceptor molecule and sucrose as a donor molecule. These compounds were identified as 1-O-benzoyl alpha-D-glucopyranoside, 2-O-benzoyl alpha-D-glucopyranose and 2-O-benzoyl beta-D-glucopyranose on the basis of their isolation and the isolation of their acetylated products and subsequent analysis using 1D- and 2D-NMR analyses. From the results of the time-course analyses of the enzyme reaction and the degradation of 1-O-benzoyl alpha-D-glucopyranoside, 1-O-benzoyl alpha-D-glucopyranoside was considered to be initially produced by the transglucosylation reaction of the enzyme, and 2-O-benzoyl alpha-D-glucopyranose and 2-O-benzoyl beta-D-glucopyranose were produced from 1-O-benzoyl alpha-D-glucopyranoside by intramolecular acyl migration reaction. The acceptor specificity in the glucosylation reaction of S. mutans sucrose phosphorylase was also investigated. This sucrose phosphorylase could transglucosylate toward various carboxylic compounds. Short-chain fatty acids, hydroxy acids and dicarboxylic acids were also glucosylated with this sucrose phosphorylase.