ACT_SITE 49; /note="Nucleophile"; /evidence="ECO:0000250"; ACT_SITE 52; /note="Nucleophile"; /evidence="ECO:0000250"; ACT_SITE 169; /note="Nucleophile"; /evidence="ECO:0000250"; ACT_SITE 172; /note="Nucleophile"; /evidence="ECO:0000250"