Biosynthesis of sucrose and its deoxy derivatives

Abstract

The biosynthesis of sucrose (β-D-fructofuranosyl-α-D-glucopyranoside) was studied in the reaction catalyzed by partially purified sucrose syntheses (UDP-D-glucose: D-fructose 2glucosyltransferase) isolated from pea seedlings, bean seedlings and sugar beet roots using UDP-D-glucose and its deoxyglucosyl derivatives as donors and D-fructose and its deoxy-analogues as acceptors. It was found that none of the hydroxyl groups either of the reaction donor or the acceptor is essential for the substrate properties in the transglycosylation reaction. The affinity of these plant enzymes and the rate of hexose incorporation into sucrose decreases however in the following sequence: sucrose, 2G-deoxysucrose, 6G-deoxysucrose, 4G-deoxysucrose, and 3G-deoxysucrose for the donor and sucrose, 6F-deoxysucrose, 1F-deoxysucrose, 4F-deoxysucrose, and 3F-deoxysucrose for the acceptor.