Lactase or LCT forms a part of the β-galactosidase family of enzymes . It is a glycoside hydrolase , primarily responsible for the hydrolysis reaction of the disaccharide lactose into galactose and glucose monomers . Lactase enzymes are mainly found along the border membrane s of differentiated enterocyte lining the villi of the small intestine in the human body. The human body encodes the lactase enzyme by LCT gene . The temperature optimum for lactase activity to take place is about 25 °C.

Uses & Benefits :

Lactase is largely produced commercially and can be extracted both from yeasts such as Kluyveromyces fragilis and Kluyveromyces lactis as well as from fungi called Aspergillus niger and Aspergillus oryzae . Its primary function is to break down lactose present in the milk and make it suitable for consumption for people suffering from lactose intolerance . Lactase is also employed for the manufacturing of ice cream . This is because since glucose and galactose are sweeter than lactose, they produce a more pleasant taste for such eatries. Lactose is also helpful in the crystallization of ice cream at low temperatures. Glucose and galactose are also responsible for rendering smooth texture of ice cream. Conversion of whey into syrup also employs the usage of Lactase.

References :

Skovbjerg H, Sjöström H, Norén O (March 1981). "Purification and characterisation of amphiphilic lactase/phlorizin hydrolase from human small intestine". Eur. J. Biochem. 114 (3): 653–61. PMID   6786877 .

Mantei N, Villa M, Enzler T, Wacker H, Boll W, James P, Hunziker W, Semenza G (September 1988). "Complete primary structure of human and rabbit lactase-phlorizin hydrolase: implications for biosynthesis, membrane anchoring and evolution of the enzyme" . EMBO J. 7 (9): 2705–13. PMID   2460343 .

Harvey CB, Fox MF, Jeggo PA, Mantei N, Povey S, Swallow DM (July 1993). "Regional localization of the lactase-phlorizin hydrolase gene, LCT, to chromosome 2q21". Ann. Hum. Genet. 57 (Pt 3): 179–85. PMID   8257087 .

Järvelä I, Torniainen S, Kolho KL (2009). "Molecular genetics of human lactase deficiencies". Ann. Med. 41 (8): 568–75. doi : 10.1080/07853890903121033 . PMID   19639477 .

Hermida C, Corrales G, Cañada FJ, Aragón JJ, Fernández-Mayoralas A (July 2007). "Optimizing the enzymatic synthesis of beta-D-galactopyranosyl-D-xyloses for their use in the evaluation of lactase activity in vivo". Bioorg. Med. Chem. 15 (14): 4836–40. doi : 10.1016/j.bmc.2007.04.067 . PMID   17512743 .

Seyis I, Aksoz N (2004). "Production of lactase by Trichoderma sp" . Food Technol Biotechnol 42 : 121–124 .

T arantino, LM (2003-12-03). "Agency Response Letter GRAS Notice No. GRN 000132" . U.S. Food and Drug Administration . Retrieved 2009-09-21 .