Oligo-1,6-glucosidase (Isomaltase)

Oligo-1,6-glucosidase, frequently known as isomaltase, is a vital digestive enzyme situated in the brush border of the small intestinal mucosa (UniProt: P14410). It plays a critical role in the final stages of carbohydrate digestion by catalyzing the hydrolysis of alpha-1,6-glucosidic linkages in isomaltose and alpha-limit dextrins, which are primary breakdown products of starch (NCBI: NBK538259). In humans, this enzyme is synthesized as a part of the bifunctional sucrase-isomaltase (SI) complex, which is later cleaved into two distinct subunits (PubMed: 25147137). A deficiency or dysfunction of this enzyme leads to Congenital Sucrase-Isomaltase Deficiency (CSID), resulting in the malabsorption of sucrose and maltose-derived dextrins, leading to gastrointestinal symptoms such as osmotic diarrhea and growth failure in infants (NORD: CSID). Therapeutically, sacrosidase is used as an enzyme replacement for the sucrase component to alleviate symptoms, while alpha-glucosidase inhibitors like miglitol target this enzyme to control postprandial glucose levels in type 2 diabetes patients (DrugBank: DB00493).

Other names

IsomaltaseDextrin 6-alpha-glucanohydrolaseSucrase-isomaltase (SI) subunitAlpha-limit dextrinase

Enzyme replacement therapy to substitute for deficient natural activity or competitive inhibition to delay the breakdown and absorption of carbohydrates in the small intestine.