Lipase ( ) is a family of

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...

s that catalyzes the

hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysi ...

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,

organism In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells ( cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and fu ...

Structure and catalytic mechanism

Classically, lipases catalyse the hydrolysis of triglycerides: :triglyceride + H₂O → fatty acid + diacylglycerol :diacylglycerol + H₂O → fatty acid + monacylglycerol :monacylglycerol + H₂O → fatty acid + glycerol Lipases are serine hydrolases, i.e. they function by transesterification generating an acyl serine intermediate. Most lipases act at a specific position on the

glycerol Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...

backbone of a lipid substrate (A1, A2 or A3). For example, human pancreatic lipase (HPL), converts

triglyceride A triglyceride (TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids (from ''tri-'' and ''glyceride''). Triglycerides are the main constituents of body fat in humans and other vertebrates, as ...

substrates found in ingested oils to monoglycerides and two

fatty acid In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, f ...

s. 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 Chymotrypsin (, chymotrypsins A and B, alpha-chymar ophth, avazyme, chymar, chymotest, enzeon, quimar, quimotrase, alpha-chymar, alpha-chymotrypsin A, alpha-chymotrypsin) is a digestive enzyme component of pancreatic juice acting in the duod ...

-like hydrolysis mechanism using a catalytic triad consisting of a

serine Serine (symbol Ser or S) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α- amino group (which is in the protonated − form under biological conditions), a carboxyl group (which is in the deprotonated − for ...

nucleophile In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they ar ...

, a

histidine Histidine (symbol His or H) is an essential amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated –NH3+ form under biological conditions), a carboxylic acid group (which is in the ...

base, and an

acid In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a se ...

residue, usually

aspartic acid Aspartic acid (symbol Asp or D; the ionic form is known as aspartate), is an α-amino acid that is used in the biosynthesis of proteins. Like all other amino acids, it contains an amino group and a carboxylic acid. Its α-amino group is in the pro ...

Physiological distribution

Lipases are involved in diverse biological processes which range from routine metabolism of dietary triglycerides to

cell signaling In biology, cell signaling (cell signalling in British English) or cell communication is the ability of a cell to receive, process, and transmit signals with its environment and with itself. Cell signaling is a fundamental property of all cellula ...

and

inflammation Inflammation (from la, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants, and is a protective response involving immune cells, blood vessels, and molec ...

. 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 In cell biology, an organelle is a specialized subunit, usually within a cell, that has a specific function. The name ''organelle'' comes from the idea that these structures are parts of cells, as organs are to the body, hence ''organelle,'' th ...

called the

lysosome A lysosome () is a membrane-bound organelle found in many animal cells. They are spherical vesicles that contain hydrolytic enzymes that can break down many kinds of biomolecules. A lysosome has a specific composition, of both its membrane p ...

. * Other lipase enzymes, such as pancreatic lipases, are secreted into

extracellular This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms. It is intended as introductory material for novices; for more specific and technical definitions ...

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 phospholipases that enhance the effects of injury and inflammation delivered by a sting. * As

biological membrane A biological membrane, biomembrane or cell membrane is a selectively permeable membrane that separates the interior of a cell from the external environment or creates intracellular compartments by serving as a boundary between one part of the ...

s are integral to living cells and are largely composed of

phospholipid Phospholipids, are a class of lipids whose molecule has a hydrophilic "head" containing a phosphate group and two hydrophobic "tails" derived from fatty acids, joined by an alcohol residue (usually a glycerol molecule). Marine phospholipids typ ...

s, lipases play important roles in

cell biology Cell biology (also cellular biology or cytology) is a branch of biology that studies the structure, function, and behavior of cells. All living organisms are made of cells. A cell is the basic unit of life that is responsible for the living an ...

. *'' Malassezia globosa'', a fungus thought to be the cause of human

dandruff Dandruff is a skin condition that mainly affects the scalp. Symptoms include flaking and sometimes mild itchiness. It can result in social or self-esteem problems. A more severe form of the condition, which includes inflammation of the skin ...

, uses lipase to break down

sebum A sebaceous gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur in the greatest nu ...

into

oleic acid Oleic acid is a fatty acid that occurs naturally in various animal and vegetable fats and oils. It is an odorless, colorless oil, although commercial samples may be yellowish. In chemical terms, oleic acid is classified as a monounsaturated o ...

and increase skin cell production, causing dandruff.

Genes In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...

encoding lipases are even present in certain

virus A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsk ...

es. Some lipases are expressed and secreted by pathogenic organisms during an

infection An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable di ...

. In particular, '' Candida albicans'' has many lipases, possibly reflecting broad- lipolytic activity, which may contribute to the persistence and virulence of ''C. albicans ''in human tissue.

Human lipases

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

Uses

In the commercial sphere, lipases are widely used in laundry detergents. Several thousand tons per year a 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 of course 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.

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 fats in those undergoing

pancreatic enzyme replacement therapy Pancreatic enzymes, also known as pancreases or pancrelipase and pancreatin, are commercial mixtures of amylase, lipase, and protease. They are used to treat malabsorption syndrome due to certain pancreatic problems. These pancreatic problems ...

(PERT). It is a component in Sollpura (Liprotamase).

References

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

External links

* {{Portal bar, Biology, border=no Hydrolases Peripheral membrane proteins EC 3.1