Lactase

Lactase
Identifiers
Symbol	LCT
Alt. Symbols	LAC; LPH; LPH1
Entrez	3938
HUGO	6530
OMIM	603202
RefSeq	NM_002299
UniProt	P09848
Other data
EC number	3.2.1.108
Locus	Chr. 2 q21

Lactase (LCT), a member 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. In humans, lactase is present predominantly along the brush border membrane of the differentiated enterocytes lining the villi of the small intestine.

Lactase is essential for digestive hydrolysis of lactose in milk. Deficiency of the enzyme causes lactose intolerance.

The optimum temperature for lactase is about 48 °C (118.4 °F) for its activity and has an optimum pH of 6.5.

Lactase is also used to screen for blue white colonies into the MCS of various plasmid vectors in E.Coli or other bacteria.

External links

• E. coli β-galactosidase: PDB 1JYY
• The use of lactases in the dairy industry
• The Recent Evolution of Lactose Tolerance
• Gene Ontology for Lactase