Phospholipase A2

Function

Phospholipase A2 (PLA2) is an enzyme which releases fatty acids from glycerol. It is found in mammals and in snake venoms^[1]. PLA2 releases arachidonic acid from membranes causing inflammation and pain. The PLA2 contains many isozymes which are ordered by groups and named accordingly, ie., group I is PLA2G1.

• PLA2 group II is induced in inflammation and present in atherosclerotic lesions^[2].
  
• PLA2 group V is active in leukocytes recruitment^[3].
  
• PLA2 group X regulates cysteinyl leukotriene synthesis^[4].
  
• PLA2 group XV is located in the endocytic system and may be involved in CD1d function^[5].
  
• PLA2 group XVI is adipose-specific^[6].
  
• Lipoprotein-associated phospholipase A2 or platelet-activating factor acetylhydrolase (Lp-PLA2) degrades platelet-activating factor and oxidized phospholipids into inactive metabolites. Platelet-activating factor is a potent phospholipid activator and mediator of inflammation, platelet aggregation and other leukocyte functions^[7].
  .
• Bothropstoxin (BTX) is PLA2 from the snake Bothrops jararacussu.
  
• Piratoxin (PTX) is PLA2 from the snake Bothrops piraña.
  
• Viperotoxin (VTX) is a heterodimer of a very homologous PLA2 called RV-4/RV-7.
  
• Cystolic PLA2 (cPLA2) is intracellular. It is larger than the secreted PLA2 and contains the targeting C2 domain.
  
• Pro-phosphlipase (PPLA2) is a pancreatic PLA2 whose 7-mer N-terminal peptide is cleaved off to produce the active PLA2.
  
• For details on Lys49 snake-venom PLA2 see Anum-II.
  
• For PLA2 complex see Diclofenac binding to Phospholipase A2.
  
• For PLA2 inhibitor see Atropine
  
• See also Phospholipase (Hebrew).

Relevance

PLA2 serve as pharmacological targets for therapeutical treatment of diseases like atherosclerosis, immune disorders, cardiovascular diseases and cancer^[8]. Reduced Lp-PLA2 activity is observed in patients with severe sepsis. There is association between the level of Lp-PLA2 in plasma and the risk of future cardiovascular events^[9].

Crystal structure of porcine pancreatic phospholipase A₂ in complex with 2-methoxycyclohexa-2-5-diene-1,4-dione

^[10]

possesses anti-inflammatory activity. The binding of curcumin with PLA₂ was studied using X-ray crystallography. Since the electron density found in the active site did not match with curcumin, (the photo-degraded product of curcumin) in the unexplained electron density. To understand the , molecular docking studies was carried out. with respect to the ligand position and identified that of PLA₂ with a binding energy -16.81 Kcal/mol. The binding mode is in such a manner that it can prevent the entry of substrate to the hydrophobic active site. These studies indicate that curcumin can be act as an inhibitor to PLA₂.