The haempeptides from cytochrome c. Exploring the basic chemistry of the iron porphyrins and modelling aspects of the haemoproteins

The haempeptides from cytochrome c, obtained by proteolysis of the parent protein, contain an iron(III) porphyrin linked by thioether bridges to a polypeptide chain. They provide an opportunity for exploring aspects of the fundamental chemistry of an iron(III) porphyrin in which one of the axial coordination sites of the metal ion is occupied by a His residue (from the parent protein) and the other contains a readily-replaced H₂O molecule. The preparation, solution properties and electronic properties of these important models for the haemoproteins are reviewed and facets of their reactions are considered.