Alternansucrase (ASR)

Alternansucrase is a glucansucrase enzyme primarily produced by the bacterium Leuconostoc mesenteroides (strain NRRL B-1355). It is responsible for the synthesis of alternan, a unique polysaccharide characterized by alternating alpha-(1,3) and alpha-(1,6) glycosidic linkages, from sucrose (UniProt: P22927). This enzyme is a member of the glycoside hydrolase family 70 (GH70) and is biologically significant for its role in extracellular polymer production, which aids in bacterial adhesion and biofilm stability (PubMed: 22442347). In a therapeutic context, alternansucrase is considered a target for the prevention of dental caries, as inhibiting related glucansucrases can prevent the formation of cariogenic biofilms (PubMed: 21873130). Beyond oral health, the enzyme is a major tool in biotechnology for the industrial production of alternan and alternan-oligosaccharides. Alternan serves as a low-viscosity, non-glycemic bulking agent and a prebiotic, which has potential applications in managing obesity and type 2 diabetes by replacing high-calorie sugars. While high-affinity clinical drugs specifically targeting alternansucrase are limited, research focuses on natural inhibitors like polyphenols and carbohydrate analogues to modulate its activity in dental and metabolic health contexts (PubMed: 11843486).

Other names

Sucrose:1,6(1,3)-alpha-D-glucan 6(3)-alpha-D-glucosyltransferaseSucrose--1,6(1,3)-alpha-D-glucan 6(3)-alpha-D-glucosyltransferaseAlpha-D-glucosyltransferaseEC 2.4.1.140

Inhibitors of alternansucrase typically act via competitive inhibition at the active site, preventing the enzyme from binding sucrose and subsequently blocking the transfer of glucose units to the growing glucan chain (PubMed: 11463131). Some molecules act as 'acceptor' substrates, diverting the enzyme from polymer synthesis to the production of small oligosaccharides (UniProt: P22927).