Heme a
From Wikipedia, the free encyclopedia
| Heme a | |
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| Identifiers | |
| CAS number | [18535-39-2] |
| PubChem | |
| MeSH | |
| Properties | |
| Molecular formula | C49H56O6N4Fe |
| Molar mass | 852.837 |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Heme A differs from heme B in that a methyl side chain at ring position 8 is oxidized into a formyl group, and one of the vinyl side chains, at ring position 2, has been replaced by an isoprenoid chain. Like heme B, heme A is often attached to the apoprotein through a coordination bond between the heme iron and a conserved amino acid side-chain.
An example of a metalloprotein that contains heme A is cytochrome c oxidase.
Both the formyl group and the isoprenoid side chain are thought to play important roles in conservation of the energy of oxygen reduction by cytochrome c oxidase.
