. "Catalysis of the reaction: siroheme + 2 H+ = Fe(2+) + sirohydrochlorin." . . "CysG" . "SirB" . "siroheme synthase activity" . "sirohydrochlorin ferrochelatase activity" . "Met8P" . "siroheme ferro-lyase (sirohydrochlorin-forming)" . "sirohydrochlorin ferro-lyase activity" . . .