1. Cytochrome c oxidase was purified from the liver mitochondria of bullfrog (Rana catesbeiana). The heme a content of the purified enzyme was 13.5 nmol per mg protein. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate revealed that the enzyme protein was composed of nine polypeptide subunits having molecular weights of 42000, 27000, 25000, 20000, 15000, 13000, 8600, 5400 and 3600. The purified enzyme from the adult frog was immunological identified with that from the tadpole. 2. The ratio of synthesis and degradation of cytochrome c oxidase were 5.2- and 2.0-times higher at metamorphic climax than at premetamorphic stage, respectively. The amount of the enzyme in the liver was highest at metamorphic climax.
Animals Electron Transport Complex IV