Platelet Activating Factor (PAF) is a biologically active phospholipid, which exerts primarily proinflammatory activities by specifically signaling through G-protein-coupled receptors on platelets, neutrophils, and monocytes. Platelet Activating Factor Acetylhydrolase (PAF-AH) is a secreted protein that mediates PAF activity by specifically catalyzing hydrolysis of the ``sn2'' ester bond, resulting in the conversion of PAF to the biologically inactive lyso-PAF. PAF-AH can also interact with LDL particles to induce the hydrolysis of LDL associated, oxidized phospholipids, generating lysophosphatidylcholine (lyso-PC) and other lysophospholipids. Recombinant PAF-AH is a 420 amino acid glycoprotein which migrates with an apparent molecular mass of 47-55 kDa by SDS-PAGE analysis.