| ULS00090 | precorrin-2 from uroporphyrinogen III | None - {{∅}} | None - {{∅}} | Unexplained |  | 
                
                    | ULS00173 | sirohydrochlorin from precorrin-2 | None - {{∅}} | None - {{∅}} | Unexplained |  | 
                
                    | UER00376 | siroheme from sirohydrochlorin: step 1/1~1 Fe2+ + 1 sirohydrochlorin => 2 H(+) + 1 siroheme. | None - {{∅}} | None - {{∅}} | Unexplained |  | 
                
                    | ULS00174 | siroheme from sirohydrochlorin | None - {{∅}} | None - {{∅}} | Unexplained |  | 
                
                    | UER00222 | sirohydrochlorin from precorrin-2: step 1/1~1 NAD(+) + 1 precorrin-2 => 1 H(+) + 1 NADH + 1 sirohydrochlorin. | None - {{∅}} | None - {{∅}} | Unexplained |  | 
                
                    | UER00211 | precorrin-2 from uroporphyrinogen III: step 1/1~2 S-adenosyl-L-methionine + 1 uroporphyrinogen III => 2 S-adenosyl-L-homocysteine + 1 precorrin-2. | None - {{∅}} | None - {{∅}} | Unexplained |  | 
                
                    | UPA00262 | siroheme biosynthesis~Biosynthesis of siroheme, the cofactor for sulfite and nitrite reductases. Siroheme is formed by methylation, oxidation, and iron insertion into the tetrapyrrole uroporphyrinogen III (Uro-III). | None - {{∅}} | None - {{∅}} | Unexplained |  |