platelet-activating factor acetyltransferase activity

Definition

Target type: molecularfunction

Catalysis of the reaction: 1-radyl-2-acyl-sn-glycero-3-phospholipid + 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine = 1-alkyl-2-lyso-sn-glycero-3-phosphocholine + 1-radyl-2-acetyl-sn-glycero-3-phospholipid. [EC:2.3.1.149, MetaCyc:2.3.1.149-RXN]

Platelet-activating factor acetyltransferase (PAF-AT) activity is a critical enzymatic process that plays a central role in the biosynthesis of platelet-activating factor (PAF), a potent bioactive lipid mediator involved in various physiological and pathological processes. PAF-AT catalyzes the transfer of an acetyl group from acetyl-CoA to the sn-2 position of lysophosphatidylcholine (LPC), converting it into PAF. This reaction occurs in the presence of a divalent metal ion, typically magnesium or manganese. The reaction mechanism involves the formation of a transient enzyme-substrate complex, followed by the transfer of the acetyl group from acetyl-CoA to the sn-2 hydroxyl group of LPC. This reaction results in the formation of PAF, which is released from the enzyme and diffuses to its target cells, mediating a wide range of biological effects. PAF-AT activity is tightly regulated by a complex interplay of factors, including substrate availability, cofactor concentration, and the activity of other enzymes involved in PAF metabolism. The precise molecular details of PAF-AT activity are still under investigation, but it is believed that the enzyme employs a two-step mechanism involving the formation of an acetyl-enzyme intermediate. This intermediate then reacts with LPC to form PAF and regenerate the free enzyme. PAF-AT is a key enzyme in the biosynthesis of PAF, and its activity is essential for the biological effects of PAF. The enzyme is expressed in a variety of cell types, including platelets, neutrophils, macrophages, and mast cells. Dysregulation of PAF-AT activity has been implicated in a variety of diseases, including asthma, atherosclerosis, and sepsis. Therefore, PAF-AT represents a promising therapeutic target for the development of novel drugs for the treatment of these conditions.'
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Proteins (2)

Compounds (2)