Lipase

 ( Hydrolases ) 

Lipase is a class of that the hydrolysis of . Some lipases display broad substrate scope including of cholesterol, , and of lipid-soluble and ; however, these are usually treated separately from "conventional" lipases. Unlike , 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 in most, if not all, .

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Structure and catalytic mechanism Classically, lipases catalyse the hydrolysis of triglycerides: $$\backslash begin\{align\}$$

 \text{triglyceride}  +  \ce{H2O}  &\longrightarrow  \text{fatty acid} + \text{diacylglycerol} \\[4pt]
 \text{diacylglycerol} + \ce{H2O}  &\longrightarrow  \text{fatty acid}  +  \text{monacylglycerol} \\[4pt]
 \text{monacylglycerol} +  \ce{H2O}  &\longrightarrow  \text{fatty acid}  +  \text{glycerol}
     

\end{align}

Lipases are , i.e. they function by transesterification generating an acyl serine intermediate. Most lipases act at a specific position on the glycerol backbone of a lipid substrate (A1, A2 or A3). For example, human pancreatic lipase (HPL), converts triglyceride substrates found in ingested oils to and two .

A diverse array of genetically distinct lipase enzymes are found in nature, and they represent several types of protein folding and catalytic mechanisms. However, most are built on an alpha/beta hydrolase fold

(1997). 9780121821852 ISBN 9780121821852

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.

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Physiological distribution 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.

• In the example of lysosomal lipase, the enzyme is confined within an organelle called the lysosome.
• Other lipase enzymes, such as pancreatic lipases, are secreted into extracellular spaces where they serve to process dietary lipids into more simple forms that can be more easily absorbed and transported throughout the body.
• Fungi and bacteria may secrete lipases to facilitate nutrient absorption from the external medium (or in examples of pathogenic microbes, to promote invasion of a new host).
• Certain wasp and bee venoms contain that enhance the effects of injury and inflammation delivered by a sting.
• As biological membranes are integral to living cells and are largely composed of , lipases play important roles in cell biology.
• Malassezia globosa, a fungus thought to be the cause of human dandruff, uses lipase to break down sebum into oleic acid and increase skin cell production, causing dandruff. Genetic Code of Dandruff Cracked – BBC News

Genes encoding lipases are even present in certain .

Some lipases are expressed and secreted by pathogenic organisms during an infection. In particular, Candida albicans has many lipases, possibly reflecting broad-lipolysis activity, which may contribute to the persistence and virulence of C. albicans in human tissue.

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Human lipases

	aids in the digestion of fats
	Cholesteryl ester storage disease (CESD) and [[Wolman disease]] are both caused by mutations in the gene encoding lysosomal lipase.[https://web.archive.org/web/20090509200200/http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=278000 Omim – Wolman Disease]
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	Lipoprotein lipase deficiency is caused by [[mutation]]s in the [[gene]] encoding lipoprotein lipase.[https://archive.today/20120708111635/http://ghr.nlm.nih.gov/condition=lipoproteinlipasedeficiencyfamilial Familial lipoprotein lipase deficiency – Genetics Home Reference]
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| lingual lipase || ? || saliva || Active at gastric pH levels. Optimum pH is about 3.5-6. Secreted by several of the (Ebner's glands at the back of the tongue (lingua), the , and the ) | –

Other lipases include , , , , , , , , , and .

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Uses In the commercial sphere, lipases are widely used in laundry detergents. Several thousand tons per year are produced for this role.

Lipases are catalysts for hydrolysis of esters and are useful outside of the cell, a testament to their wide substrate scope and ruggedness. The ester hydrolysis activity of lipases has been well evaluated for the conversion of triglycerides into biofuels or their precursors.

Lipases are chiral, which means that they can be used for the enantioselective hydrolysis prochiral diesters. Several procedures have been reported for applications in the synthesis of fine chemicals.

Lipases are generally animal sourced, but can also be sourced microbially.

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Biomedicine

Blood tests for lipase may be used to help investigate and diagnose acute pancreatitis and other disorders of the pancreas. Measured serum lipase values may vary depending on the method of analysis.

Lipase assist in the breakdown of in those undergoing pancreatic enzyme replacement therapy (PERT). It is a component in Sollpura (Liprotamase)."Anthera Pharmaceuticals – Sollpura." Anthera Pharmaceuticals – Sollpura. N.p., n.d. Web. 21 July 2015. .

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See also

• Alpha toxin
• Pathology
• Lysosomal acid lipase deficiency
• Peripheral membrane proteins
• Phospholipase A
• Phospholipase C
• Triglyceride lipase
• Phospholipase A2
• Outer membrane phospholipase A1
• Patatin-like phospholipase

25. Gulzar, Bio-degradation of hydrocarbons using different bacterial and fungal species. Published in international conference on biotechnology and neurosciences. CUSAT (cochin university of science and technology), 2003

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External links

Categories: Hydrolases, Peripheral Membrane Proteins, Ec 3.1

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