Determination of catalytic activity, covalent binding to biotin–fumagillin, and tryptic digestion pattern of MetAP2 mutants. (A) Methionine aminopeptidase activity of mutant and wild type (WT) MetAP2 and their sensitivity to ovalicin. (B) Near-Western blot of WT, H231A, C227A, and H339A MetAP2 mutants by using biotin–fumagillin.