Molecular Regulation of Starch Metabolism

Starch is the main storage carbohydrate in plants. Thus, when photosynthesis is inactive, plants are sprouting, and seeds are germinating, starch provides energy and carbon skeletons to fulfill plant growth requirements. Relatively few enzymatic activities are necessary for starch synthesis and degradation. However, starch metabolism is complex due to the high number of isoforms present for each enzymatic activity. The mechanisms of regulations of these isoforms are diverse, and in many cases, they depend on the organ or species analyzed. These mechanisms include allosteric regulation by metabolites, redox regulation, phosphorylation, and protein–protein interactions.