Lactase

Enzyme involved in the digestion of lactose

Lactase

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Crystal structure of lactase

Lactase is an enzyme that is essential for the complete digestion of whole milk; it breaks down lactose, a sugar which gives milk its sweetness. Lactase is produced by many organisms, including humans, and is located in the brush border of the small intestine. The enzyme is crucial for the digestion of lactose in the diet, and its deficiency can lead to lactose intolerance.

Function

Lactase is responsible for the hydrolysis of lactose into its constituent sugars, glucose and galactose. This reaction is necessary for the absorption of these sugars into the bloodstream. The enzyme works by cleaving the β-glycosidic bond in lactose, a disaccharide, to yield the two monosaccharides.

Mechanism of lactase action on lactose

Lactase Production

Lactase is produced by the enterocytes lining the small intestine. The production of lactase is highest in infants, who rely on milk as their primary source of nutrition. As humans age, the production of lactase typically decreases, which can lead to lactose intolerance in adulthood.

Processing of lactase in the small intestine

Lactose Intolerance

Lactose intolerance is a common condition caused by a deficiency of lactase. Individuals with lactose intolerance experience symptoms such as bloating, diarrhea, and abdominal pain after consuming lactose-containing foods. This condition is more prevalent in certain populations, particularly those of East Asian, West African, Arab, Jewish, Greek, and Italian descent.

Therapeutic Use

Lactase supplements are available for individuals with lactose intolerance. These supplements can be taken orally to aid in the digestion of lactose-containing foods. Additionally, lactase is used in the dairy industry to produce lactose-free products by pre-digesting the lactose in milk.

Also see

• Lactose intolerance
• Enzyme
• Disaccharide
• Glucose
• Galactose