| Accepted Name |
|---|
| corrinoid adenosyltransferase EutT
|
| Reaction catalysed |
|---|
| 2 ATP + 2 cob(II)alamin + 2 H2O + reduced [electron-transfer flavoprotein] <=> 2 adenosylcob(III)alamin + 2 diphosphate + 3 H(+) + oxidized [electron-transfer flavoprotein] + 2 phosphate |
| Comment(s) |
|---|
- The corrinoid adenosylation pathway comprises three steps.
- (i) reduction of Co(III) within the corrinoid 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 the de novo biosynthesis and the salvage of
adenosylcobalamin), the pduO gene (involved in (S)-propane-1,2-diol
utilization), and the eutT gene (involved in ethanolamine
utilization).
- The first two types, which produce triphosphate, are classified as
EC 2.5.1.17, while the EutT type hydrolyzes triphosphate to
diphosphate and phosphate during catalysis and is thus classified
separately.
|
| Cross-references |
|---|
| BRENDA | 2.5.1.154 |
| EC2PDB | 2.5.1.154 |
| ExplorEnz | 2.5.1.154 |
| PRIAM enzyme-specific profiles | 2.5.1.154 |
| KEGG Ligand Database for Enzyme Nomenclature | 2.5.1.154 |
| IUBMB Enzyme Nomenclature | 2.5.1.154 |
| IntEnz | 2.5.1.154 |
| MEDLINE | Find literature relating to 2.5.1.154 |
| MetaCyc | 2.5.1.154 |
| Rhea expert-curated reactions | 2.5.1.154 |
| UniProtKB/Swiss-Prot |
|
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