Lipase

Lipase refers to a family of enzymes that catalyze the hydrolysis of lipids, most importantly the triglycerides that make up dietary and stored fat. Chemically they are serine hydrolases, using a catalytic trio of serine, histidine, and aspartate residues to cleave the bonds that hold fatty acids to a glycerol backbone. A defining feature of true lipases is interfacial activation: they work best at the boundary between oil and water, where a lid-like surface loop swings open to expose the active site, an arrangement first revealed when the structure of human pancreatic lipase was solved by X-ray crystallography ^[1].

In humans, several distinct lipases handle different jobs. Pancreatic lipase, secreted into the small intestine, is the principal enzyme for digesting the fat in food, while gastric and lingual lipases begin the process in the stomach and mouth. Other members of the family act in the bloodstream and tissues rather than the gut: lipoprotein lipase and hepatic lipase process circulating fat-carrying particles, and a lysosomal lipase breaks down fats inside cells. Lipases are also produced abundantly by bacteria and fungi.

Because the pancreas is rich in lipase, the enzyme has become an important medical marker. When the pancreas is inflamed, as in acute pancreatitis, lipase leaks into the blood and its level rises; a blood lipase test is now the preferred laboratory tool for diagnosing the condition, offering better sensitivity and a longer window of detection than the older amylase test ^[2].

Lipase is also given as a treatment. In exocrine pancreatic insufficiency, a condition in which the pancreas fails to release enough digestive enzymes, patients cannot properly absorb fat and develop symptoms such as greasy stools, weight loss, and vitamin deficiencies. The standard therapy is pancreatic enzyme replacement, in which capsules containing lipase along with protease and amylase, derived from pig pancreas, are taken with meals to restore normal digestion ^[3]. Several such products are approved and regulated as prescription medicines ^[4]. Lipase is additionally sold in over-the-counter digestive-enzyme supplements, sometimes from microbial or plant sources.

Outside of medicine, lipases are among the most commercially useful enzymes. They are added to laundry detergents to break down grease and oil stains, used in the food industry to develop flavors in cheese and to modify fats, and applied in the production of biofuels and fine chemicals, where their ability to act selectively on particular molecules is valued.

Generally safe and well tolerated. High-dose prescription pancreatic enzymes carry specific risks in certain conditions, but over-the-counter lipase is low risk. People with pancreatitis or serious pancreatic disease should use enzymes under medical guidance.