(A) Structure of human MGL showing cysteine residues C201 and C208 (on the cap domain, red) and C242 (close to catalytic nucleophile S122). (B) Effects of H2O2 on wild-type MGL (filled circles), MGL mutants C201A (filled diamonds), C208A (filled triangles) or C201/208A (empty squares) and DGL-α (filled squares). (C) Time-course of MGL inhibition by H2O2 (10 μM: shaded squares; 100 μM: filled squares). (D) Kinetics of MGL inhibition by H2O2 (vehicle: open circles). (E) Rapid dilution of MGL incubated with vehicle (circles), H2O2 (filled squares; 10 μM final), or irreversible inhibitor methylarachidonylfluorophosphonate (MAFP, inverted triangles, 23 nM final). (F) Effects of H2O2 on wild-type MGL (filled circles) and MGL C242 mutants C242A (inverted triangles) and C242S (triangles).