lipase

Lipase refers to a family of enzymes that cleave ester bonds in lipids, most notably triglycerides, into glycerol and free fatty acids. They are serine hydrolases that catalyze hydrolysis at lipid–water interfaces, often via a catalytic triad of serine, histidine, and aspartate and a conserved motif around the active serine (such as GXSXG). In mammals, the principal digestive lipase is pancreatic lipase, which acts in the small intestine with the aid of colipase and bile salts; gastric and lingual lipases also contribute to fat digestion, particularly for certain substrates and at different pH levels.

Beyond digestion, lipases include lipoprotein lipase (LPL) and hepatic lipase (HL) that act on circulating triglyceride-rich lipoproteins, hydrolyzing triglycerides to release fatty acids for tissue uptake. LPL is anchored to the vascular endothelium and requires apolipoprotein C-II as a cofactor; HL is associated with the liver and acts on both chylomicrons and VLDL remnants. In addition to mammalian enzymes, many microbial lipases are used in industry and research.

Clinically, measurement of serum lipase is used in diagnosing pancreatitis and monitoring pancreatic injury; it can remain elevated longer than amylase. Inhibitors of pancreatic lipase, such as orlistat, reduce fat absorption and are used in obesity management. Lipases are employed in food processing, detergents, and biodiesel production, and are widely used as biochemical tools in lipid metabolism studies.