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ENZYME entry: EC 1.17.99.9

Accepted Name
Heme a synthase.
Reaction catalysed
Ferroheme o + H(2)O + 2 acceptor <=> ferroheme a + 2 reduced acceptor
Comment(s)
  • Contains a heme b cofactor.
  • The enzyme catalyzes the conversion of heme o to heme a by two successive hydroxylations of the methyl group at C-8, using water as the oxygen source.
  • The first hydroxylation forms heme i, the second hydroxylation results in an unstable dihydroxymethyl group, which spontaneously dehydrates, resulting in the formyl group of heme a.
  • The electrons produced by the reaction are transferred to a heme b cofactor.
  • However, the electron acceptor that is used to restore the heme b cofactor to its oxidized state is still not known (both a thioredoxin-like protein and menaquinol have been proposed).
Cross-references
BRENDA1.17.99.9
EC2PDB1.17.99.9
ExplorEnz1.17.99.9
PRIAM enzyme-specific profiles1.17.99.9
KEGG Ligand Database for Enzyme Nomenclature1.17.99.9
IUBMB Enzyme Nomenclature1.17.99.9
IntEnz1.17.99.9
MEDLINEFind literature relating to 1.17.99.9
MetaCyc1.17.99.9
Rhea expert-curated reactions1.17.99.9

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