Lactose

Lactose is the sugar making up around 2-8% of the solids in milk. The name comes from the Latin word for milk, plus the -ose ending used to name sugars. Lactose is a disaccharide consisting of two subunits, a galactose and a glucose linked together. Its empirical formula is C12H22O11 and its molecular weight is 342.3. In the young of mammals, an enzyme called lactase is secreted by the intestinal villi, and this enzyme cleaves the molecule into its two subunits for absorption.

See also

• lactose intolerance
• Lac operon