Cytochromes are

Cytochromes These are very impoant enzymes which contain haem and are involved in cellular oxidation. ( Fe-porphyrin protein) The oxidized form of cytochrome possesses a single Fe+3 ion and is called ferricytochrome. It is reduced to ferrocytochrome having a Fe+2 ion on accepting an electron. * Cytochromes are identified by their characteristic absorption spectra. Ferricytochrome shows diffuse and non-characteristic absorption band invisible spectrum. Ferrocytochrome exhibit characteristic absorption bands called a aa, b bb, and ggg-soret bands. * Cytochromes are categorized into different groups according to the light wavelength at which the a-band shows its peak (a absorption maxima). They also differ with respect to haem prosthetic group, the apoprotein, and binding between the haem and apoprotein.Ref: MN Chatterjea Textbook of Medical Biochemistry, 8th edition, page no: 137