Table 1.
Relationship of bovine and yeast cytochrome oxidase subunits
| Bovine subunit | Yeast subunit | Yeast gene | Subunit contacta | Activityb | Assemblyc |
|---|---|---|---|---|---|
| I | 1 | COX1 | 2, 3, 4, 5a | − | − |
| II | 2 | COX2 | 1, 6b, 7a | − | − |
| III | 3 | COX3 | 1, 4, 7, 5a, 6b | − | − |
| IV | 5a | COX5a | 1, 6 | − | − |
| Va | 6 | COX6 | 5a, 7a | − | − |
| Vb | 4 | COX4 | 1, 3 | − | − |
| VIa | 6a | COX13 | 3 | + | +/− |
| VIb | 6b | COX12 | 2, 3 | +/− | + |
| VIc | 7a | COX9 | 2, 6 | − | − |
| VIIa | 7 | COX7 | 3 | − | − |
| VIIb | |||||
| VIIc | 8 | COX8 | 1 | + | + |
| VIII |
a The subunit contacts are those reported for bovine COX (1).
b The presence (+) or absence (−) of COX activity is based on the ability of isolated yeast mitochondria to catalyze cyanide sensitive oxidation of ferrocytochrome c.
c The failure of COX subunits to assemble in the absence of a subunit is indicated as −. Normal levels of assembled COX are indicated by +, and reduced levels are indicated by +/−.