– The phospholipases are an extensive family of lipid hydrolases that function in cell signaling, digestion, membrane remodeling, and as venom components. The calcium-independent phospholipases (iPLA2) are a PLA2 subfamily closely associated with the release of arachidonic acid in response to physiologic stimuli. (R)-Bromoenol lactone ((R)-BEL) is an irreversible, chiral, mechanism-based inhibitor of calcium-independent phospholipase γ (iPLA2γ). Unlike (S)-BEL, (R)-BEL does not inhibit iPLA2β except at high doses of 20-30 μM. (R)-BEL inhibits human recombinant iPLA2γ with an IC50 of approximately 0.6 μM.