Phospholipase A



Phospholipase A is an enzyme that hydrolytically cleaves phospholipids. Phospholipase A is divided into phospholipase A1 and phospholipase A2, they cleave different bonds in the phosholipid. Both are contained in lysosomes and in the digestive tract, where they have a digestive function.

Phospholipase A1
An enzyme that cleaves the acyl at position 1 in a phospholipid.

Phospholipase A2
It cleaves the acyl in position 2 from the phospholipid. Unsaturated fatty acids, such as arachidonic acid, are often found in this position. The release of arachidonate is an important step for some signaling pathways – both arachidonic acid itself and other substances derived from it (eicosanoids) have a signaling function. Enzymes with phospholipase 2 activity are also part of the venom of some snakes and spiders. The rest of the phospholipid that remains after sn-2 fatty acid cleavage (lysophospholipid) in the extracellular space has a haemolytic effect. After being bitten by some species of snakes and spiders, acute, even fatal, intravascular hemolysis can occur. In humans, extracellular phospholipase 2 is produced in pancreas as a proenzyme, it requires trypsin and Ca2+ ions for its activation.

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 * Enzyme structure
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 * Phospholipases