Studies on copper–protoporphyrin–iron(III) complexes. A possible model for cytochrome c oxidase

Abstract

Methods for preparing copper–protoporphyrin–iron(III) complexes are presented. Comparison of the properties of these complexes with haematin and µ-oxo-dimeric haematin clearly shows that the complexes are distinct new species. Infrared spectroscopy provides evidence for the copper binding to protoporphyrin propionate groups. Mössbauer and e.s.r. spectroscopy provide evidence for high-spin iron(III) and copper(II). There is some evidence for interactions between the two metal nuclei. A possible structure is presented and its properties are discussed in terms of the known behaviour of cytochrome c oxidase.