ACT_SITE 74; /note="Nucleophile"; /evidence="ECO:0000250|UniProtKB:P07237"; ACT_SITE 77; /note="Nucleophile"; /evidence="ECO:0000250|UniProtKB:P07237"; ACT_SITE 421; /note="Nucleophile"; /evidence="ECO:0000250|UniProtKB:Q13087"; ACT_SITE 424; /note="Nucleophile"; /evidence="ECO:0000250|UniProtKB:Q13087"