Introduction
Pancreatic (EC 3.1.1.3) is secreted from the pancreas and is the primary enzyme that breaks down lipids in the digestive system. It converts triglyceride substrates to monoglycerides and free fatty acids. [1]
Structure
The structure of human pancreatic lipase has been solved, but a refined version has not been published. Horse pancreatic lipase, on the other hand, has been solved and published. Horse pancreatic lipase (PDB ID 1hpl) consists of 449 amino acids and 705 well-defined water molecules in two subunits, and . Its consists of 22% and 30% . Lipase also binds two as ligands. It contains both and . The overall molecular structure of horse lipase has two well-defined domains.The N-terminal domain contains the active site and has a typical alpha/beta hydrolase fold topology. The C-terminal domain, for colipase binding, has a beta-sheet sandwich topology.[2]
Function
Most lipases act at a specific position on the glycerol backbone of the lipid substrate.[3] Bile salts aid lipase in fat hydrolysis by increasing the surface area of fats.
Unlike many proteases, pancreatic lipase is secreted in its final form. However, it is only active in the presence of in the duodenum. Colipase is also secreted in the pancreas, but in its inactive form, procolipase, which is activated by trypsin in the intestinal lumen. Colipase prevent the inhibitory effect of bile salts on the lipase-catalyzed intraduodenal hydrolysis of dietary long-chain triglycerides.[4]
References
- ↑ "Pancreatic lipase". Wikipedia: The Free Encyclopedia. 7 Nov 2011 [1]
- ↑ Bourne Y, Martinez C, Kerfelec B, Lombardo D, Chapus C, Cambillau C. 1994. Horse pancreatic lipase. J. mol Biol. 238: 709-732.
- ↑ "Lipase". Wikipedia: The Free Encyclopedia. 6 Nov 2011 [2]
- ↑ "Colipase". Wikipedia: The Free Encyclopedia. 5 July 2011 [3]
