IUBMB Enzyme Nomenclature


Accepted name: siroheme decarboxylase

Reaction: siroheme = 12,18-didecarboxysiroheme + 2 CO2

For diagram of reaction click here.

Other name(s): sirohaem decarboxylase; nirDLHG (gene name); ahbABC (gene name)

Systematic name: siroheme carboxy-lyase

Comments: The enzyme from archaea is involved in an alternative heme biosynthesis pathway. The enzyme from denitrifying bacteria is involved in the heme d1 biosynthesis pathway.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number:


1. Bali, S., Lawrence, A.D., Lobo, S.A., Saraiva, L.M., Golding, B.T., Palmer, D.J., Howard, M.J., Ferguson, S.J. and Warren, M.J. Molecular hijacking of siroheme for the synthesis of heme and d1 heme. Proc. Natl Acad. Sci. USA 108 (2011) 18260-18265. [PMID: 21969545]

2. Kuhner, M., Haufschildt, K., Neumann, A., Storbeck, S., Streif, J. and Layer, G. The alternative route to heme in the methanogenic archaeon Methanosarcina barkeri. Archaea 2014 (2014) 327637. [PMID: 24669201]

3. Palmer, D.J., Schroeder, S., Lawrence, A.D., Deery, E., Lobo, S.A., Saraiva, L.M., McLean, K.J., Munro, A.W., Ferguson, S.J., Pickersgill, R.W., Brown, D.G. and Warren, M.J. The structure, function and properties of sirohaem decarboxylase--an enzyme with structural homology to a transcription factor family that is part of the alternative haem biosynthesis pathway. Mol. Microbiol. 93 (2014) 247-261. [PMID: 24865947]

4. Haufschildt, K., Schmelz, S., Kriegler, T.M., Neumann, A., Streif, J., Arai, H., Heinz, D.W. and Layer, G. The crystal structure of siroheme decarboxylase in complex with iron-uroporphyrin III reveals two essential histidine residues. J. Mol. Biol. 426 (2014) 3272-3286. [PMID: 25083922]

[EC created 2018]

Return to EC 4.1.1 home page
Return to EC 4.3 home page
Return to EC 4 home page
Return to Enzymes home page
Return to IUBMB Biochemical Nomenclature home page