Phospholipase A2 ( EC 3.1.1.4 , English phospholipase A2 ) is a type of phospholipase that hydrolyzes the acyl chain of a phospholipid in the sn-2 position. Under the action of phospholipase A2 on a phospholipid, 2-lysophospholipid and fatty acid are formed . Various fatty acids, including arachidonic and eicosapentaenoic acids, can be located in the sn-2 position of the phospholipid.
Content
- 1 Families
- 1.1 Secreted phospholipases A2
- 1.2 Cytosolic phospholipases A2
- 1.3 Phospholipase A2 of the outer membrane
- 2 See also
- 3 References
Families
Phospholipases A2 include several unrelated protein families with a common enzymatic activity. The two most important families are secreted and cytosolic phospholipases A2.
A2 secreted phospholipases
Extracellular forms of phospholipases A2 were isolated from various poisons of snakes , bees and wasps . They are also found in all tissues of mammals and in bacteria . The activity of these phospholipases requires calcium .
Pancreatic phospholipase A2 refers to digestive enzymes and is involved in the digestion of food lipids. Poison phospholipases are involved in immobilization of the victim due to lysis of its cells.
A2 cytosolic phospholipases
Intracellular phospholipases, as well as extracellular, belong to calcium- dependent enzymes. Structurally, however, they are very different from secreted phospholipases. As a rule, they are significantly larger (more than 700 amino acids) and contain a C2 domain , which directs the enzyme to the cell membrane.
These phospholipases are mainly involved in cellular signaling pathways, such as the inflammatory response . Under the action of phospholipases A2, arachidonic acid , a precursor of eicosanoids , such active signaling molecules as leukotrienes and prostaglandins, can form in the cell.
Outer membrane phospholipase A2
Gram-negative bacteria contain phospholipase A2 with a wide range of specificity on the outer membrane. In E. coli ( Escherichia coli ), this enzyme is involved in the release of bacteriocin toxin from the cell due to increased membrane permeability with an increase in the level of lysophospholipids and fatty acids in the membrane.
See also
- Lipoprotein Associated Phospholipase A2
- PLA2G5
- Membrane-associated phospholipase A2 (PLA2G2A)
Links
- Phospholipase
- http://humbio.ru/humbio/biochem/0015f53b.htm Acylglycerols, metabolism: glycerophospholipids and plasmalogens
- OMPLA in Pfam (link not available)