Lactase

Definition
noun, plural: lactases
An enzyme that catalyze the hydrolysis and subsequently the breakdown of lactose into glucose and galactose
Supplement
Lactases belong to a group of enzymes that hydrolyze the disaccharide lactose. Their catalytic activity results in the splitting of lactose into constituent monomers, glucose and galactose.
Lactases are secreted in the small intestine, kidneys, and liver of mammals. In humans, they are found mainly along the brush border membrane of the enterocytes that line the villi of the small intestine.¹ LCT gene is the one that codes for lactases. Lactases digest lactose in milk and dairy products. Without this enzyme, the individual would not be able to digest lactose and as a result show symptoms of lactose intolerance. Thus, there are dairy products that add lactase in dairy products. Lactase is essential to digest lactose in humans to digest and break it down into D-galactose and D-glucose, which are absorbed through the intestinal walls and into the bloodstream.
See also:

• lactose
• glucose
• galactose
• enzyme
• hydrolysis

Related term(s):

Pro-lactase-phlorizin hydrolase

Deficiency lactase

Adult lactase deficiency

Reference(s):

¹ 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.