Lipoprotein lipase

Lipases are enzymes that degrade fats. The major lipase in milk is lipoprotein lipase. It is associated with the casein micelle. Lipoprotein lipase activity has been found in the milks from several species where it is assumed to result from leakage from the mammary gland into milk.

The LPL gene provides instructions for making an enzyme called lipoprotein lipase. This enzyme is found primarily on the surface of cells that line tiny blood vessels (capillaries) within muscles and in fatty (adipose) tissue.

The function of the enzyme in the gland is apparently to assist in the transfer of blood lipoprotein triacylglycerol fatty acids into milk triacylglycerols. Bovine skim milk is one of the richest sources of lipoprotein lipase.

The total lipase activity in raw milk is sufficient to cause rapid hydrolysis of a large proportion of the fat. However, in reality this does not happen, because the lipase is prevented from accessing the fat by the milkfat globule membrane. The lipase is unable to hydrolyze the triglycerides of cream and would be destroyed in the digestive tract in any case.

In cheese manufacturing, lipase is utilized to separate milk fat and gives desirable flavors to the cheese. Lipase is mostly used in cheese maturing for the improvement of flavors. Lactase is usually applied to hydrolyze lactose to glucose and galactose sugars and increase the solubility and sweet flavor in different dairy items.
Lipoprotein lipase