Platelet-activating factor acetylhydrolase (PAF-AH) is a subfamily of phospholipases A2 (group-VIIA), responsible for inactivation of platelet-activating factor through cleavage of an acetyl group (PAF: Extracellular signaling lipid; ligand for G protein-coupled platelet activating factor (PAF) receptors). Three known PAF-AHs are the brain heterotrimeric PAF-AH Ib, (whose subunits are not alpha/beta hydrolases), the extracellular, plasma PAF-AH (pPAF-AH), and the intracellular PAF-AH isoform II (PAF-AH II). Both these last two forms are alpha/beta hydrolases and are included in this family. Lipoprotein-associated phospholipase A2 (Lp-PLA2) also known as platelet-activating factor acetylhydrolase (PAF-AH) is a phospholipase A2 enzyme that in humans is encoded by the PLA2G7 gene (human-PLA2G7). This family also contains microbial lipase homologue of PAF-AH_p_II. The first sructure known was Streptomyces exfoliatus lipase
This family also contains microbial lipase homologue of PAF-AH_p_II. The first sructure known was Streptomyces exfoliatus lipase