Lipase

A lipase (/ˈlaɪpeɪs/, /-peɪz/) is any enzyme that catalyzes the hydrolysis of fats (lipids). Lipases are a subclass of the esterases.General formula of a carboxylate esterGlycerol A lipase (/ˈlaɪpeɪs/, /-peɪz/) is any enzyme that catalyzes the hydrolysis of fats (lipids). Lipases are a subclass of the esterases. Lipases perform essential roles in digestion, transport and processing of dietary lipids (e.g. triglycerides, fats, oils) in most, if not all, living organisms. Genes encoding lipases are even present in certain viruses. Most lipases act at a specific position on the glycerol backbone of a lipid substrate (A1, A2 or A3)(small intestine). For example, human pancreatic lipase (HPL), which is the main enzyme that breaks down dietary fats in the human digestive system, converts triglyceride substrates found in ingested oils to monoglycerides and two fatty acids. Several other types of lipase activities exist in nature, such as phospholipases and sphingomyelinases; however, these are usually treated separately from 'conventional' lipases. Some lipases are expressed and secreted by pathogenic organisms during an infection. In particular, Candida albicans has a large number of different lipases, possibly reflecting broad-lipolytic activity, which may contribute to the persistence and virulence of C. albicans in human tissue. A diverse array of genetically distinct lipase enzymes are found in nature, and they represent several types of protein folds and catalytic mechanisms. However, most are built on an alpha/beta hydrolase fold and employ a chymotrypsin-like hydrolysis mechanism using a catalytic triad consisting of a serine nucleophile, a histidine base, and an acid residue, usually aspartic acid. Lipases are involved in diverse biological processes which range from routine metabolism of dietary triglycerides to cell signaling and inflammation. Thus, some lipase activities are confined to specific compartments within cells while others work in extracellular spaces. The main lipases of the human digestive system are pancreatic lipase (PL) and pancreatic lipase related protein 2 (PLRP2), which are secreted by the pancreas. Humans also have several related enzymes, including hepatic lipase, endothelial lipase, and lipoprotein lipase. Not all of these lipases function in the gut (see table). Other lipases include LIPH, LIPI, LIPJ, LIPK, LIPM, LIPN, MGLL, DAGLA, DAGLB, and CEL.