ON THE NATURE OF HEMOPROTEIN REACTIONS 



PHILIP GEORGE, Department of Colloid Science, Cambridge University' 



A Survey 



In biochemistry and physiology, hemoproteins are im- 

 portant because of the roles they play in biological oxidation, 

 on the one hand, transporting and storing oxygen, and on the 

 other, acting as catalysts in certain of the oxidation processes. 

 In physicochemical studies, which have as their aim an under- 

 standing of the mechanism by which chemical reactions take 

 place, hemoprotein reactions are important too, because they 

 show a specificity which is more highly evolved than that of any 

 other class of enzyme. Furthermore they exemplify particularly 

 well two of the ways in which a protein can influence the reaction 

 of a prosthetic group — an effect which is to be distinguished 

 from the determination by the protein of the specific reaction 

 undergone by the prosthetic group. Interaction can occur 

 between the prosthetic group and an acidic group on the 

 protein, which on dissociation alters the affinity of the enzyme 

 for its substrate. Interaction can occur between prosthetic 

 groups themselves, if there are more than one on each molecule, 

 the protein in some way providing a "pathway" by which the 

 groups influence each other. 



* Present address: Department of Chemistry, University of Pennsylvania, 

 Philadelphia, Pa. 



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