Bile, or gall, is a yellow-green fluid produced by the liver of most vertebrates that aids the digestion of lipids in the small intestine. In humans, bile is primarily composed of water, produced continuously by the liver, and stored and concentrated in the gallbladder. After a human eats, this stored bile is discharged into the first section of their small intestine.
Lipoprotein lipase (LPL) (EC 3.1.1.34, systematic name triacylglycerol acylhydrolase (lipoprotein-dependent)) is a member of the lipase gene family, which includes pancreatic lipase, hepatic lipase, and endothelial lipase. It is a water-soluble enzyme that hydrolyzes triglycerides in lipoproteins, such as those found in chylomicrons and very low-density lipoproteins (VLDL), into two free fatty acids and one monoacylglycerol molecule:
Perilipin, also known as lipid droplet-associated protein, perilipin 1, or PLIN, is a protein that, in humans, is encoded by the PLIN gene. The perilipins are a family of proteins that associate with the surface of lipid droplets. Phosphorylation of perilipin is essential for the mobilization of fats in adipose tissue.
Lipid metabolism is the synthesis and degradation of lipids in cells, involving the breakdown and storage of fats for energy and the synthesis of structural and functional lipids, such as those involved in the construction of cell membranes. In animals, these fats are obtained from food and are synthesized by the liver. Lipogenesis is the process of synthesizing these fats. The majority of lipids found in the human body from ingesting food are triglycerides and cholesterol. Other types of lipids found in the body are fatty acids and membrane lipids. Lipid metabolism is often considered the digestion and absorption process of dietary fat; however, there are two sources of fats that organisms can use to obtain energy: from consumed dietary fats and from stored fat. Vertebrates use both sources of fat to produce energy for organs such as the heart to function. Since lipids are hydrophobic molecules, they need to be solubilized before their metabolism can begin. Lipid metabolism often begins with hydrolysis, which occurs with the help of various enzymes in the digestive system. Lipid metabolism also occurs in plants, though the processes differ in some ways when compared to animals. The second step after the hydrolysis is the absorption of the fatty acids into the epithelial cells of the intestinal wall. In the epithelial cells, fatty acids are packaged and transported to the rest of the body.
Hormone-sensitive lipase (EC 3.1.1.79, HSL), also previously known as cholesteryl ester hydrolase (CEH), sometimes referred to as triacylglycerol lipase, is an enzyme that, in humans, is encoded by the LIPE gene, and catalyzes the following reaction:
Gastric lipase, also known as LIPF, is an enzymatic protein that, in humans, is encoded by the LIPF gene.
Bile salt-dependent lipase, also known as carboxyl ester lipase is an enzyme produced by the adult pancreas and aids in the digestion of fats. Bile salt-stimulated lipase is an equivalent enzyme found within breast milk. BSDL has been found in the pancreatic secretions of all species in which it has been looked for. BSSL, originally discovered in the milk of humans and various other primates, has since been found in the milk of many animals including dogs, cats, rats, and rabbits.
Non-specific lipid-transfer protein also known as sterol carrier protein 2 (SCP-2) or propanoyl-CoA C-acyltransferase is a protein that in humans is encoded by the SCP2 gene.
In molecular biology the PLAT domain is a protein domain that is found in a variety of membrane or lipid associated proteins. It is called the PLAT domain or LH2 domain. The known structure of pancreatic lipase shows this domain binds to procolipase Pfam PF01114, which mediates membrane association.
Phospholipase A2, group 1B is an enzyme that in humans is encoded by the PLA2G1B gene.
Fatty acid binding protein 6, ileal (gastrotropin), also known as FABP6, is a protein which in humans is encoded by the FABP6 gene.
Adipose triglyceride lipase, also known as patatin-like phospholipase domain-containing protein 2 and ATGL, is an enzyme that in humans is encoded by the PNPLA2 gene. ATGL catalyses the first reaction of lipolysis, where triacylglycerols are hydrolysed to diacylglycerols.
Pancreatic secretory granule membrane major glycoprotein GP2 is a protein that in humans is encoded by the GP2 gene.
Triglyceride lipases are a family of lipolytic enzymes that hydrolyse ester linkages of triglycerides. Lipases are widely distributed in animals, plants and prokaryotes.
Phospholemman (PLM) is a protein that in humans is encoded by the FXYD1 gene.
Acyl-protein thioesterase 1 is an enzyme that in humans is encoded by the LYPLA1 gene.
Bile acyl-CoA synthetase is an enzyme that in humans is encoded by the SLC27A5 gene.
CYP8B1 also known as sterol 12-alpha-hydroxylase is a protein which in humans is encoded by the CYP8B1 gene.
In biochemistry, lipase refers to a class of enzymes that catalyzes the hydrolysis of fats. Some lipases display broad substrate scope including esters of cholesterol, phospholipids, and of lipid-soluble vitamins and sphingomyelinases; however, these are usually treated separately from "conventional" lipases. Unlike esterases, which function in water, lipases "are activated only when adsorbed to an oil–water interface". Lipases perform essential roles in digestion, transport and processing of dietary lipids in most, if not all, organisms.
ANGPTL8 is a protein that in humans is encoded by the C19orf80 gene.
