Haem Proteins

Abstract

Haem proteins are widely distributed in cellular systems, catalysing a variety of reactions, primarily oxidation-reduction processes essential for respiration and production of metabolic energy. A variety of haem proteins with widely different biological reactivities and specificities are known (see reference 87). However, three-dimensional structures have been determined by diffraction methods only for myoglobins^10–13,88, haemoglobins of both mammalian and lower-order species^14–18,89, calf-liver calf-liver cytochrome b₅^21,90, and oxidised horse heart¹⁹ and reduced bonito-tuna²⁰ cytochrome c. Structural investigations have been initiated on yeast cytochrome c peroxidase^23,24. Also, a variety of difference Fourier studies have been carried out on sperm-whale myoglobin^66,70,91–3 and haemoglobins^94–7.