Role of Uridine Diphosphate Glucose in the Biosynthesis of Starch

摘要: A potato particulate preparation, which is constituted mainly by proplastids, was capable of glucose transfer from micromolar concentrations uridine diphosphate [14C]glucose into an endogenous protein molecule to form a 14C-labelled glucoprotein. This glucoprotein had short radioactive glucan chains and could act as acceptor for the synthesis larger labelled glucose, either at millimolar or in presence 1-phosphate adenosine concentrations. last step required Mn2+ Mg2+ ions. The enzyme responsible formation glucoproteic named glucose-protein transglucosylase I its properties were studied. The activity, that detected 1-phosphate, be distinguished glucose–protein following criteria: The dependent activity ions, sensitive temperature formed totally hydrolyzed β-amylase. Conversely, active absence resistent scarcely attacked β-amylase. Sequential analysis incorporation [3H]glucose sodium dodecylsulphate–acrylamide gel electrophoresis glucoproteins carried out. On basis data obtained simple scheme reactions proposed explain involvement activities α-1,4 starch type.