Starch synthase (SS (with specific isoforms denoted as SS1, SS2, SS3, SS4, and GBSS))

Starch synthase is an enzyme crucial for the biosynthesis of starch in plants. It catalyzes the transfer of glucose from ADP-glucose to the non-reducing end of a growing chain of 1,4-alpha-D-glucosyl residues, creating new alpha 1-4 glycosidic bonds and thereby elongating the starch polymer. There are multiple isoforms, including granule-bound starch synthase (GBSS) which is responsible for amylose synthesis, and soluble starch synthase isoforms (SS1, SS2, SS3, SS4) which are involved in the synthesis of amylopectin. The activity and composition of these enzymes affect the physical and chemical structure of starch granules, influencing properties important in plant physiology and the agricultural processing of starch crops. Starch synthase isoforms physically interact with other starch biosynthetic enzymes, such as branching and debranching enzymes, to form multienzyme complexes that increase the efficiency of starch production[2][3][5][7][8]. Caveats and limitations: - Starch synthase is an essential plant enzyme, not recognized as a direct therapeutic target in humans nor a typical receptor or drug target[5][2]. - No clinically relevant drugs, biomarkers, or safety concerns are associated with starch synthase in current medical or pharmaceutical practice. Its importance is in agriculture, plant genetics, and biotechnology[5][2][7][8].

Other names

ADP-glucose:1,4-alpha-D-glucan 4-alpha-D-glucosyltransferaseADP-glucose-starch glucosyltransferaseadenosine diphosphate glucose-starch glucosyltransferaseadenosine diphosphoglucose-starch glucosyltransferaseADP-glucose starch synthaseADP-glucose synthaseADP-glucose transglucosylaseADPG starch synthetaseADPG-starch glucosyltransferase

No therapeutic drugs; mechanism involves transfer of glucose from ADP-glucose to non-reducing end of glucan chains.