The Reduced minus Oxidized Difference Spectra of Cytochromes a and a3. Guang-Ling Liao and Graham Palmer,

Biochim Biophys Acta (submitted)

SUMMARY We have re-investigated the reduced minus oxidized difference spectra of the two heme centers of cytochrome oxidase, cytochromes a and a3. In contrast to data obtained in an earlier study (Vanneste, W.H. (1966) Biochem. 5 838-848). we find that the spectrum for cytochrome a3 agrees with that found with a 5-coordinate high-spin heme A model compound. Small but significant differences additional differences are noted for both heme centers.