Lipase
You don't need to be Editor-In-Chief to add or edit content to WikiDoc. You can begin to add to or edit text on this WikiDoc page by clicking on the edit button at the top of this page. Next enter or edit the information that you would like to appear here. Once you are done editing, scroll down and click the Save page button at the bottom of the page.
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Phone:617-525-6884
Please Take Over This Page and Apply to be Editor-In-Chief for this topic: There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us [2] to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.
Overview
A lipase is a water-soluble enzyme that catalyzes the hydrolysis of ester bonds in water–insoluble, lipid substrates[1]. Lipases thus comprise a subclass of the esterases.
Lipases are ubiquitous throughout living organisms, and genes encoding lipases are even present in certain viruses. [1][1]
Function
Most lipases act at a specific position on the glycerol backbone of a lipid substrate (A1, A2 or A3).
In the example of human pancreatic lipase (HPL)[1], which is the main enzyme responsible for breaking down fats in the human digestive system, a lipase acts to convert triglyceride substrates found in oils from food to monoglycerides and free fatty acids.
Myriad other lipase activities exist in nature, especially when the phospholipases[1] and sphingomyelinases[1] are considered.
Structure
While a diverse array of genetically distinct lipase enzymes are found in nature, and represent several types of protein folds and catalytic mechanisms, most are built on an alpha/beta hydrolase fold [1][1][1] (see image[1]) and employ a chymotrypsin-like hydrolysis mechanism involving a serine nucleophile, an acid residue (usually aspartic acid), and a histidine[1][1].
Location of action
Some lipases work within the interior spaces of living cells to degrade lipids.
- Other lipase enzymes, such as pancreatic lipases, are found in the spaces outside of cells and have roles in the metabolism, absorption and transport of lipids throughout the body.
As biological membranes are integral to living cells and are largely composed of phospholipids, lipases play important roles in cell biology.
Furthermore, lipases are involved in diverse biological processes ranging from routine metabolism of dietary triglycerides to cell signaling[1] and inflammation[1].
Lipases of Humans
The main lipases in the human digestive system are human pancreatic lipase (HPL) and pancreatic lipase related protein 2 (PLRP2), which are secreted by the pancreas. Humans also have several other related enzymes, including hepatic lipase (HL), endothelial lipase, and lipoprotein lipase. Not all of these lipases function in the gut (see table).
| Name | Gene | Description | Disorder |
| pancreatic lipase | PNLIP | In order to exhibit optimal enzyme activity in the gut lumen, HPL requires another protein, colipase, which is also secreted by the pancreas[1]. | - |
| lysosomal lipase | LIPA | Also referred to as lysosomal acid lipase (LAL or LIPA) or acid cholesteryl ester hydrolase | Cholesteryl ester storage disease (CESD) and Wolman disease are both caused by mutations in the gene encoding lysosomal lipase.[1] |
| hepatic lipase | LIPC | Hepatic lipase acts on the remaining lipids carried on lipoproteins in the blood to regenerate LDL (low density lipoprotein). | - |
| lipoprotein lipase | LPL or "LIPD" | Lipoprotein lipase functions in the blood to act on triacylglycerides carried on VLDL (very low density lipoprotein) so that cells can take up the freed fatty acids. | Lipoprotein lipase deficiency is caused by mutations in the gene encoding lipoprotein lipase.[1] [1] |
| hormone-sensitive lipase | LIPE | - | - |
| gastric lipase | LIPF | Functions in the infant at a near-neutral pH to aid in the digestion of lipids | - |
| endothelial lipase | LIPG | - | - |
| pancreatic lipase related protein 2 | PNLIPRP2 or "PLRP2" | - | - |
| pancreatic lipase related protein 1 | PNLIPRP1 or "PLRP1" | Pancreatic lipase related protein 1 is very similar to PLRP2 and HPL by amino acid sequence (all three genes probably arose via gene duplication of a single ancestral pancreatic lipase gene). However, PLRP1 is devoid of detectable lipase activity and its function remains unknown, even though it is conserved in other mammals[1][1]. | - |
Other lipases include LIPH, LIPI, LIPJ, LIPK, LIPM, and LIPN.
There also are a diverse array of phospholipases, but these are not always classified with the other lipases.
Industrial Uses
Lipases from fungi and bacteria serve important roles in human practices as ancient as yogurt and cheese fermentation. However, lipases are also being exploited as cheap and versatile catalysts to degrade lipids in more modern applications. For instance, a biotechnology company has brought recombinant lipase enzymes to market for use in applications such as baking, laundry detergents and even as biocatalysts [1] in alternative energy strategies to convert vegetable oil into fuel. [1][1]
Additional images
 General formula of a carboxylate ester |
 General structure of a triglyceride |
References
External links
- MeSH Lipase
- Selective Inhibitors of Monoacylglycerol Lipase as a Treatment for Neurological Disorders 2004-637
- UMich Orientation of Proteins in Membranes families/superfamily-90 - Phospholipases A2
- UMich Orientation of Proteins in Membranes families/superfamily-29 - Outer membrane phospholipase A
- UMich Orientation of Proteins in Membranes families/superfamily-134 - Cytosolic phospholipase A2 and patatin
- UMich Orientation of Proteins in Membranes families/superfamily-126 - Bacterial and mammalian phospolipases C
- UMich Orientation of Proteins in Membranes families/superfamily-88 - α-toxin (a bacterial phospholipase C)
See also
da:Lipasede:Lipasefr:Lipase nl:Lipase ja:リパーゼ no:Lipasefi:Lipaasi sv:Lipas
Acknowledgement and Attribution Regarding Sources of Content
Some of the initial content on this page may be incorporated in part from copyleft sources in the public domain including wikis such as Wikipedia and AskDrWiki. Drug information for patients came from the The National Library of Medicine. Infectious disease information may have come from the Centers for Disease Control (CDC). Differential Diagnoses are drawn from clinicians as well as an amalgamation of 3 sources: 1.The Disease Database; 2. Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:3; 3. Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:7 .
