Studies

Summary Glycogen is the principal carbon reserve in Synechocystis sp. PCC 6803. We reconstituted its biosynthetic pathway in vitro—GlgC (Glucose-1-phosphate adenylyltransferase), two glycogen synthase isoenzymes (GlgA1, GlgA2) and the branching enzyme GlgB—to define how supply, polymerisation and branching set flux and product structure. GlgA2 shows higher specific activity and cooperates with GlgB-generated branched primers, whereas GlgA1 has higher substrate affinity and responds more to primer ...

Abstract The enzyme Glucose-1-phosphate adenylyltransferase (GlgC, EC:2.7.7.27) catalyses the first step in glycogen synthesis by converting glucose-1-phosphate into ADP-Glucose, which is added in turn to a growing glycogen chain by glycogen synthases. Thus far, the in vitro study of GlgC were mainly performed using colorimetric or radiolabel-based phosphate release assays, limiting the option for analysing this reaction. With this work, we present a novel in vitro continuous assay coupling the ...