A 'lipase' is a water-soluble enzyme that catalyzes the hydrolysis of ester chemical bonds in water-insoluble lipid substrates.[1] Lipases thus comprises a subclass of the esterases An esterase is a hydrolase enzyme that splits esters into an acid and an alcohol in a chemical reaction with water called hydrolysis.
Lipases perform essential roles in the digestion, transport and processing of dietary lipids (e.g. triglycerides Triglyceride is an ester derived from glycerol and three fatty acids. It is the main constituent of vegetable oil and animal fats, fats Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. Chemically, fats are generally triesters of glycerol and fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure and composition. Although the words "oils", "fats",, oils An oil is any substance that is liquid at ambient temperatures and is hydrophobic but soluble in organic solvents. Oils have a high carbon and hydrogen content and are nonpolar substances. The general definition above includes compound classes with, and uses, including vegetable oils, petrochemical oils, and volatile essential oils. All oils can) in most, if not all, living organisms In biology, an organism is any contiguous living system . In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homoeostasis as a stable whole. An organism may either be unicellular (single-celled) or be composed of, as in humans, many trillions of cells grouped into. Genes A gene is a unit of heredity in a living organism. It is normally a stretch of DNA that codes for a type of protein or for an RNA chain that has a function in the organism. All living things depend on genes, as they specify all proteins and functional RNA chains. Genes hold the information to build and maintain an organism's cells and pass genetic encoding lipases are even present in certain viruses A virus is a small infectious agent that can replicate only inside the living cells of organisms. Most viruses are too small to be seen directly with a light microscope. Viruses infect all types of organisms, from animals and plants to bacteria and archaea. Since the initial discovery of tobacco mosaic virus by Martinus Beijerinck in 1898, about 5,.[2][3]
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Function
Most lipases act at a specific position on the glycerol Glycerol is an organic compound, also called glycerin or glycerine. It is a colourless, odourless, viscous liquid that is widely used in pharmaceutical formulations. Glycerol has three hydrophilic hydroxyl groups that are responsible for its solubility in water and its hygroscopic nature. The glycerol substructure is a central component of many backbone of lipid substrate (A1, A2 or A3). For example, human pancreatic lipase (HPL),[4] which is the main enzyme to break down fats Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. Chemically, fats are generally triesters of glycerol and fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure and composition. Although the words "oils", "fats", in the human Humans, known taxonomically as Homo sapiens , are the only living species in the Homo genus of bipedal primates in Hominidae, the great ape family. However, in some cases "human" is used to refer to any member of the genus Homo digestive system Digestion is the mechanical and chemical breaking down of food into smaller components that can be absorbed into a blood stream, for instance. Digestion is a form of catabolism: a break-down of larger food molecules to smaller ones, converts triglyceride Triglyceride is an ester derived from glycerol and three fatty acids. It is the main constituent of vegetable oil and animal fats substrates found in ingested oils to monoglycerides A monoglyceride, more correctly known as a monoacylglycerol, is a glyceride consisting of one fatty acid chain covalently bonded to a glycerol molecule through an ester linkage and free fatty acids In chemistry, especially biochemistry, a fatty acid is a carboxylic acid with a long unbranched aliphatic tail , which is either saturated or unsaturated. The most occurring natural fatty acids have an even number of carbon atoms because their biosynthesis involves acetyl-CoA, a coenzyme carrying a two-carbon-atom group (see fatty acid synthesis).
Several other types of lipase activities exist in nature, such as phospholipases A phospholipase is an enzyme that hydrolyzes phospholipids into fatty acids and other lipophilic substances. There are four major classes, termed A, B, C and D distinguished by what type of reaction they catalyze:[5] and sphingomyelinases[6], however these are usually treated separately from "conventional" lipases.
Structure and catalytic mechanism
While a diverse array of genetically Genetics , a discipline of biology, is the science of heredity and variation in living organisms. The fact that living things inherit traits from their parents has been used since prehistoric times to improve crop plants and animals through selective breeding. However, the modern science of genetics, which seeks to understand the process of distinct lipase enzymes are found in nature, and represent several types of protein folds Protein folding is the physical process by which a polypeptide folds into its characteristic and functional three-dimensional structure from random coil. Each protein exists as an unfolded polypeptide or random coil when translated from a sequence of mRNA to a linear chain of amino acids. This polypeptide lacks any developed three-dimensional and catalytic mechanisms, most are built on an alpha/beta hydrolase fold[7][8][9] (see image[10]) and employ a chymotrypsin Chymotrypsin is a digestive enzyme that can perform proteolysis. Chymotrypsin preferentially cleaves peptide amide bonds where the carboxyl side of the amide bond is a tyrosine, tryptophan, or phenylalanine. These amino acids contain an aromatic ring in their sidechain that fits into a 'hydrophobic pocket' (the S1 position) of the enzyme. The-like hydrolysis mechanism involving a serine Serine is an organic compound with the formula H nucleophile, an acid An acid in common usage is a substance that tastes sour, reacts with metals and carbonates, turns blue litmus paper red, and has a pH less than 7.0 in its standard state. Examples include acetic acid (in vinegar) and sulfuric acid (used in car batteries). Acid/base reactions differ from redox reactions in that there is no change in oxidation state residue (usually aspartic acid Aspartic acid is an α-amino acid with the chemical formula HO2CCH(NH2)CH2CO2H. The carboxylate anion of aspartic acid is known as aspartate. The L-isomer of aspartate is one of the 20 proteinogenic amino acids, i.e., the building blocks of proteins. Its codons are GAU and GAC), and a histidine Histidine is one of the 22 proteinogenic amino acids. In terms of nutrition, histidine is considered an essential amino acid in human infants. After reaching several years of age, humans begin to synthesize it, at which point it becomes a non-essential amino acid. Its codons are CAU and CAC.[11][12]
Physiological distribution
Lipases are involved in diverse biological processes ranging from routine metabolism of dietary In nutrition, diet is the sum of food consumed by a person or other organism. Dietary habits are the habitual decisions an individual or culture makes when choosing what foods to eat. With the word diet, it is often implied the use of specific intake of nutrition for health or weight-management reasons . Although humans are omnivores, each culture triglycerides Triglyceride is an ester derived from glycerol and three fatty acids. It is the main constituent of vegetable oil and animal fats to cell signaling Cell signaling is part of a complex system of communication that governs basic cellular activities and coordinates cell actions. The ability of cells to perceive and correctly respond to their microenvironment is the basis of development, tissue repair, and immunity as well as normal tissue homeostasis. Errors in cellular information processing[13] and inflammation Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process. Inflammation is not a synonym for infection. Even in cases where inflammation is.[14] Thus, some lipase activities are confined to specific compartments within cells The cell is the functional basic unit of life. It was discovered by Robert Hooke and is the functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. Some organisms, such as most bacteria, are unicellular . Other organisms, such as humans, 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 within a cell that has a specific function, and is usually separately enclosed within its own lipid bilayer called the lysosome Lysosomes are spherical organelles that contain enzymes that break up endocytized materials and cellular debris. They are found in animal cells, while in yeast and plants the same roles are performed by lytic vacuoles. Lysosomes digest excess or worn-out organelles, food particles, and engulfed viruses or bacteria. The membrane around a lysosome.
- Other lipase enzymes, such as pancreatic The pancreas is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland producing several important hormones, including insulin, glucagon, and somatostatin, as well as an exocrine gland, secreting pancreatic juice containing digestive enzymes that pass to the small intestine. These enzymes help to further lipases, are secreted into extracellular In cell biology, molecular biology and related fields, the word extracellular means "outside the cell". This space is usually taken to be outside the plasma membranes, and occupied by fluid. The term is used in contrast to intracellular (inside the cell) 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 A phospholipase is an enzyme that hydrolyzes phospholipids into fatty acids and other lipophilic substances. There are four major classes, termed A, B, C and D distinguished by what type of reaction they catalyze: that enhance the "biological payload" of injury and inflammation delivered by a sting.
- As biological membranes A biological membrane or biomembrane is an enclosing or separating amphipathic layer that acts as a barrier within or around a cell. It is almost invariably a lipid bilayer, composed of a double layer of lipid molecules and proteins that may constitute close to 50% of membrane content are integral to living cells and are largely composed of phospholipids Phospholipids are a class of lipids and are a major component of all cell membranes as they can form lipid bilayers. Most phospholipids contain a diglyceride, a phosphate group, and a simple organic molecule such as choline; one exception to this rule is sphingomyelin, which is derived from sphingosine instead of glycerol. The first phospholipid, lipases play important roles in cell biology Cell biology is an academic discipline that studies cells – their physiological properties, their structure, the organelles they contain, interactions with their environment, their life cycle, division and death. This is done both on a microscopic and molecular level. Cell biology research encompasses both the great diversity of single-celled.
- Malassezia globosa, a fungus that is thought to be the cause of human dandruff Pityriasis simplex capillitii is the shedding of dead skin cells from the scalp (not to be confused with a dry scalp). Dandruff is sometimes caused by frequent exposure to extreme heat and cold. As it is normal for skin cells to die and flake off, a small amount of flaking is normal and common. Some people, however, either chronically or as a, uses lipase to break down sebum The sebaceous glands are microscopic glands in the skin which secrete an oily/waxy matter, called sebum, to lubricate the skin and hair of mammals. In humans, they are found in greatest abundance on the face and scalp, though they are distributed throughout all skin sites except the palms and soles. In the eyelids, meibomian sebaceous glands into oleic acid Oleic acid is a mono-unsaturated omega-9 fatty acid found in various animal and vegetable sources. It has the formula CH37CH=CH(CH2)7COOH. The trans-isomer of oleic acid is called elaidic acid and increase skin cell production, causing dandruff. [15]
Human lipases
The main lipases of the human digestive system Digestion is the mechanical and chemical breaking down of food into smaller components that can be absorbed into a blood stream, for instance. Digestion is a form of catabolism: a break-down of larger food molecules to smaller ones are human pancreatic lipase (HPL) and pancreatic lipase related protein 2 (PLRP2), which are secreted by the pancreas The pancreas is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland producing several important hormones, including insulin, glucagon, and somatostatin, as well as an exocrine gland, secreting pancreatic juice containing digestive enzymes that pass to the small intestine. These enzymes help to further. Humans also have several other related enzymes, including hepatic lipase Hepatic lipase is a form of lipase. It is expressed in the liver and adrenal glands (HL), endothelial lipase, and lipoprotein lipase Lipoprotein lipase is an enzyme that hydrolyzes lipids in lipoproteins, such as those found in chylomicrons and very low-density lipoproteins (VLDL), into two free fatty acids and one monoacylglycerol molecule. It requires Apo-CII as a cofactor. Not all of these lipases function in the gut (see table).
Other lipases include LIPH, LIPI, LIPJ, LIPK, LIPM, LIPN, MGLL, DAGLA, DAGLB, and CEL.
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[22] in alternative energy strategies to convert vegetable oil into fuel.[23][24]
Pseudomonas and some fungal lipases also can be used for degradation of crude oil Gulzar., Wingene Biotech Research Labs, Bangalore
Additional images
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General formula of a carboxylate ester |
General structure of a triglyceride |
See also
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Mon, 06 Sep 2010 04:10:28 GMT+00:00
Chemie.de (press release) Brenna and her colleagues have developed a method that allows a mixture of isomers to be differentiated, and it depends on the use of the enzyme lipase PS. ...
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Lipase und pankrea www drclark com gif
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Wed, 25 Nov 2009 04:54:00 GM
CALB stands for the enzyme . lipase. B specificly isolated from the yeast-like fungus Candida antarctica. CALB exhibits hydrolytic, ester synthesis and transesterification activity. It is a versatile biocatalyst, for example in asymmetric ...
Q. About a month ago, I had some severe stomach pains. The pain would then redirect to my back - some of the worst pain I've ever encountered. I went to the doctor and got some blood work done and they said that my pancreatic lipase levels were high. Just two weeks before, I had stopped taking Alli and I know Alli inhibits lipase enzymes. I was just wondering if anyone can verify if there is a connection between the two.
Asked by Terri S - Wed Sep 17 16:55:04 2008 - - 2 Answers - 0 Comments
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Answered by Joann P - Wed Sep 17 20:50:06 2008
