platelet-activating factor acetylhydrolase 1B (PAF acetylhydrolase 1B, PAFAH1B)

Function

• inactivates PAF by removing the acetyl group at the sn-2 position
• cytosolic PAF-AH 1B is formed of 3 subunits
  • PAFAH1B1 (alpha)
  • PAFAH1B2 (beta)
  • PAFAH1B3 (gamma)

1-alkyl-2-acetyl-sn-glycero-3-phosphocholine + H2O
                 <-->
1-alkyl-sn-glycero-3-phosphocholine + acetate

Structure

• catalytic activity of the enzyme resides in the beta & gamma subunits
• the alpha subunit has regulatory activity.
• trimer formation is NOT essential for the catalytic activity

More general terms

• molecular complex
• hydrolase