Lactase (LCT)

Lactase, a part of the β-galactosidase family of enzymes, is a glycoside hydrolase involved in the hydrolysis of the disaccharide lactose into constituent galactose and glucose monomers. Lactase is present predominantly along the brush border membrane of the differentiated enterocytes lining the villi of the small intestine. In humans, lactase is encoded by the LCT gene. Lactase is essential for digestive hydrolysis of lactose in milk. Deficiency of the enzyme causes lactose intolerance.The optimum temperature for lactase is about 25 °C for its activity and has an optimum pH of 6.Lactase can hydrolyze a variety of substrates. While it is most notably a member of the β-galactosidase enzymatic class, lactase also has glucosidase and glycosylceramidase activity.