| Role | Gene | Name | |
|---|
| 5-aminolevulinate synthase (EC 2.3.1.37) | SMc03104 | | |
| Coproporphyrinogen III oxidase, aerobic (EC 1.3.3.3) | SMc00180 | | |
| Coproporphyrinogen III oxidase, oxygen-independent (EC 1.3.99.22) | SMa1266 | | |
| Coproporphyrinogen III oxidase, oxygen-independent (EC 1.3.99.22), divergent, putative | No genes | | |
| Coproporphyrinogen III oxidase, oxygen-independent (EC 1.3.99.22), divergent, putative 2 | No genes | | |
| Distant homolog of E. coli HemX protein in Xanthomonadaceae | No genes | | |
| Ferrochelatase, protoheme ferro-lyase (EC 4.99.1.1) | SMc04019 | | |
| Glutamate-1-semialdehyde aminotransferase (EC 5.4.3.8) | SMa0956 | | |
| Glutamyl-tRNA reductase (EC 1.2.1.70) | No genes | | |
| Glutamyl-tRNA synthetase (EC 6.1.1.17) | No genes | | |
| HemX protein, negative effector of steady-state concentration of glutamyl-tRNA reductase | No genes | | |
| Hemoprotein HemQ, essential component of heme biosynthetic pathway in Gram-positive bacteria | No genes | | |
| Hypothetical membrane protein, possible involvement in cytochrome functioning/assembly | No genes | | |
| Hypothetical radical SAM family enzyme, NOT coproporphyrinogen III oxidase, oxygen-independent | No genes | | |
| Porphobilinogen deaminase (EC 2.5.1.61) | SMc03231 | | |
| Porphobilinogen synthase (EC 4.2.1.24) | SMc01766 | | |
| Precorrin-2 oxidase (EC 1.3.1.76) | SM_b20987 | | |
| | SMc01053 | | |
| Protoporphyrinogen IX oxidase, aerobic (EC 1.3.3.4) | No genes | | |
| Protoporphyrinogen IX oxidase, oxygen-independent, HemG (EC 1.3.-.-) | No genes | | |
| Putative coproporphyrinogen III oxidase of BS HemN-type, oxygen-independent (EC 1.3.99.22), in heat shock gene cluster | No genes | | |
| Radical SAM family enzyme, similar to coproporphyrinogen III oxidase, oxygen-independent, clustered with nucleoside-triphosphatase RdgB | SMc01147 | | |
| Radical SAM family protein HutW, similar to coproporphyrinogen III oxidase, oxygen-independent, associated with heme uptake | No genes | | |
| Sirohydrochlorin ferrochelatase (EC 4.99.1.4) | SM_b20987 | | |
| | SMc01053 | | |
| Uroporphyrinogen III decarboxylase (EC 4.1.1.37) | SMc02794 | | |
| Uroporphyrinogen-III methyltransferase (EC 2.1.1.107) | SM_b20987 | | |
| | SMc01053 | | |
| | SMc04284 | | |
| Uroporphyrinogen-III synthase (EC 4.2.1.75) | SMc03232 | | |
| Uroporphyrinogen-III synthase, divergent, Flavobacterial type (EC 4.2.1.75) | No genes | | |
| Uroporphyrinogen-III synthase, divergent, Francisella type (EC 4.2.1.75) | No genes | | |