Isolation and characterization of cytochrome c oxidase from bird and fish heart mitochondria

1. Several bird and fish heart mitochondrial cytochrome c oxidases have been isolated with a rapid and simple method involving hydrophobic and affinity chromatography. 2. Their spectrophotometric and kinetic properties are very similar to those of the mammalian enzymes. 3. These oxidases show a polypeptide composition simpler than the mammalian enzymes being composed of 9-10, instead of 13, different polypeptides. 4. These data suggest that the complexity of the mitochondrial heart oxidase increases with the stage of evolution.