| Accepted Name |
|---|
| corrinoid adenosyltransferase
|
| Alternative Name(s) |
|---|
| aquacob(I)alamin adenosyltransferase |
| aquocob(I)alamin vitamin B12s adenosyltransferase |
| ATP:cob(I)alamin Cobeta-adenosyltransferase |
| ATP:corrinoid adenosyltransferase |
| cob(I)alamin adenosyltransferase |
| cob(I)yrinic acid a,c-diamide adenosyltransferase |
| Reaction catalysed |
|---|
- 2 cob(II)alamin + reduced [electron-transfer flavoprotein] + 2 ATP = 2 adenosylcob(III)alamin + 2 triphosphate + oxidized [electron-transfer flavoprotein] + 3 H(+)
- 2 cob(II)yrinate a,c diamide + reduced [electron-transfer flavoprotein] + 2 ATP = 2 adenosylcob(III)yrinate a,c-diamide + 2 triphosphate + oxidized [electron-transfer flavoprotein] + 3 H(+)
|
| Comment(s) |
|---|
- The corrinoid adenosylation pathway comprises three steps: (i)
reduction of Co(III) to Co(II) by a one-electron transfer.
- This can occur non-enzymically in the presence of dihydroflavin
nucleotides or reduced flavoproteins.
- (ii) Co(II) is bound by corrinoid adenosyltransferase, resulting in
displacement of the lower axial ligand by an aromatic residue.
- The reduction potential of the 4-coordinate Co(II) intermediate is
raised by ~250 mV compared with the free compound, bringing it to
within physiological range.
- This is followed by a second single-electron transfer from either
free dihydroflavins or the reduced flavin cofactor of flavoproteins,
resulting in reduction to Co(I).
- (iii) the Co(I) conducts a nucleophilic attack on the adenosyl moiety
of ATP, resulting in transfer of the deoxyadenosyl group and
oxidation of the cobalt atom to Co(III) state.
- Three types of corrinoid adenosyltransferases, not related by
sequence, have been described.
- In the anaerobic bacterium Salmonella enterica they are encoded by
the cobA gene (a housekeeping enzyme involved in both
adenosylcobalamin de novo biosynthesis and salvage), the pduO gene
(involved in (S)-propane-1,2-diol utilization), and the eutT gene
(involved in ethanolamine utilization).
- Since EutT hydrolyzes triphosphate during catalysis, it is classified
as a separate enzyme.
- The mammalian enzyme belongs to the PduO type.
- The enzyme can act on other corrinoids, such as cob(II)inamide.
- Formerly EC 1.16.8.1.
|
| Cross-references |
|---|
| BRENDA | 2.5.1.17 |
| EC2PDB | 2.5.1.17 |
| ExplorEnz | 2.5.1.17 |
| KEGG Ligand Database for Enzyme Nomenclature | 2.5.1.17 |
| IUBMB Enzyme Nomenclature | 2.5.1.17 |
| MEDLINE | Find literature relating to 2.5.1.17 |
| MetaCyc | 2.5.1.17 |
| Rhea expert-curated reactions | 2.5.1.17 |
| UniProtKB/Swiss-Prot |
| P45515, ATR_CITFR | P0A9H6, BTUR_ECOL6 | P0A9H5, BTUR_ECOLI |
| P31570, BTUR_SALTY | Q9I472, COBO_PSEAE | P29930, COBO_SINSX |
| O34899, PDUO_BACSU | P64804, PDUO_MYCBO | P53523, PDUO_MYCLE |
| P9WP98, PDUO_MYCTO | P9WP99, PDUO_MYCTU |
|
