ACT_SITE 171; /note="Nucleophile"; /evidence="ECO:0000250|UniProtKB:P07098"; ACT_SITE 342; /note="Charge relay system"; /evidence="ECO:0000255|PROSITE-ProRule:PRU10037"; ACT_SITE 371; /note="Charge relay system"; /evidence="ECO:0000255|PROSITE-ProRule:PRU10037"