| EC |
1.3.98.3 |
| Accepted name: |
coproporphyrinogen dehydrogenase |
| Reaction: |
coproporphyrinogen III + 2 S-adenosyl-L-methionine = protoporphyrinogen IX + 2 CO2 + 2 L-methionine + 2 5′-deoxyadenosine |
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For diagram of porphyrin biosynthesis (later stages), click here |
| Other name(s): |
oxygen-independent coproporphyrinogen-III oxidase; HemN; coproporphyrinogen III oxidase |
| Systematic name: |
coproporphyrinogen-III:S-adenosyl-L-methionine oxidoreductase (decarboxylating) |
| Comments: |
This enzyme differs from EC 1.3.3.3, coproporphyrinogen oxidase, by using S-adenosyl-L-methionine (AdoMet) instead of oxygen as oxidant. It occurs mainly in bacteria, whereas eukaryotes use the oxygen-dependent oxidase. The reaction starts by using an electron from the reduced form of the enzyme’s [4Fe-4S] cluster to split AdoMet into methionine and the radical 5′-deoxyadenosin-5′-yl. This radical initiates attack on the 2-carboxyethyl groups, leading to their conversion into vinyl groups. This conversion, —·CH-CH2-COO- → —CH=CH2 + CO2 + e- replaces the electron initially used. |
| Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, PDB |
| References: |
| 1. |
Layer, G., Verfürth, K., Mahlitz, E. and Jahn, D. Oxygen-independent coproporphyrinogen-III oxidase HemN from Escherichia coli. J. Biol. Chem. 277 (2002) 34136–34142. [DOI] [PMID: 12114526] |
| 2. |
Layer, G., Moser, J., Heinz, D.W., Jahn, D. and Schubert, W.D. Crystal structure of coproporphyrinogen III oxidase reveals cofactor geometry of radical SAM enzymes. EMBO J. 22 (2003) 6214–6224. [DOI] [PMID: 14633981] |
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| [EC 1.3.98.3 created 2004 as EC 1.3.99.22, transferred 2016 to EC 1.3.98.3] |
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