Inhibition of sucrose synthetase cleavage activity by protein factors

Abstract

1. Introduction 2. Materials and methods Sucrose synthetase (UDP-glucose: D-fructose 2-cu-D-glucosyltransferase, EC 2.4.1.13) catalyzes the synthesis and cleavage of sucrose. It is the only trans- glycosylation reaction involving sugar nucleotides that is readily reversible. The enzyme shows a wide specificity for the nucleoside base, unlike most enzymes of sugar nucleotide metabolism which are specific for a particular base [ 11. The enzyme exhibits differences in some properties between the forward and backward reaction: different cleavage and synthe- sis pH optima[2-51, buffers [2-61, temperature [6] and trypsin action [7] as well as activation or inhibi- tion by mercaptoethanol [ 51, metal ions [ 5-8,9], phenylglycosides [lo] and ATP [9-l 11. All chemicals were purchased from Sigma (St Louis MO). Wheat seeds