| Abstract: | Low concentrations of EDTA (in the presence of Ca2+ excess) or o-phenanthroline cause a blue shift of the oxidized cytochrome oxidase Soret absorption band. The effect develops within approximately 2 hours and does not depend on EDTA concentration provided the complexon is in a molar excess over the enzyme. It is suggested that the enzyme spectral characteristics depend on the presence of some tightly bound heavy metal ions which can stabilize one of the spectrally distinct conformations of cytochrome c oxidase. |
