Category: sugar
Aliases: Table sugar, Saccharose, Cane sugar, Beet sugar, Sugar, Sucrose, beta-D-fructofuranosyl alpha-D-glucopyranoside
Sucrose is a non-reducing disaccharide of α-D-glucose and β-D-fructose joined by a 1,2-glycosidic bond. It is not absorbed intact: brush-border sucrase-isomaltase hydrolyses it in the proximal small intestine to free [[glucose]] and [[fructose]]. Glucose (and galactose) is taken up apically by the Na+-coupled cotransporter SGLT1; fructose enters via the facilitative transporter GLUT5; both exit the enterocyte basolaterally through GLUT2. Absorbed glucose raises blood sugar and stimulates pancreatic [[insulin]] secretion, whereas fructose is cleared largely first-pass by hepatic fructokinase (ketohexokinase) and is poorly insulinotropic. Systemic disposition is therefore that of the two monosaccharides, not the parent. Sucrose is the reference standard of relative sweetness (defined as 1.0) and is fully fermentable by oral bacteria, making it cariogenic.