Oxidative Mechanisms in Animal Tissues 



ERIC G. BALL 



Harvard Medical School 



LIFE REQUIRES energy, and the study of life processes has resolved 

 J itself largely into a study of various manifestations of the 

 utilization of energy by the living organism. The source of this 

 energy necessary for life was first indicated by the work of Lavoisier 

 in 1770. Since then it has become increasingly recognized, as F. G. 

 Hopkins has said, that "among the most fundamental of the dynamic 

 chemical events related to life are the oxidations which yield energy 

 to the cell." 



Today we know a good deal about the oxidative processes taking 

 place within the living cell, and we know a little about the amount 

 of energy such processes may yield. We do not know, however, 

 whether all the energy released by oxidative processes is utilized by 

 the cell nor how it is utilized. Further knowledge concerning this 

 aspect of the subject must perforce await fuller understanding of the 

 mechanisms involved in the energy-yielding oxidative processes. 

 That we are, however, upon the threshold of the solution is wit- 

 nessed by the recent developments linking phosphorylation with 

 oxidative processes in the living cell. It may well be that this 

 symposium on respiratory enzymes and phosphorylation processes 

 will mark a milestone in our advance. Let me, therefore, as my part 

 in it, review briefly for you what we know today about the oxidative 

 mechanisms in animal tissues and the energy they may yield. 



Any consideration of the oxidative mechanisms in animal tissues 

 has naturally centered about two points, oxygen and the organic 

 substance undergoing oxidation. Outside the living cell oxygen does 

 not react with the foodstuffs of the cell to any appreciable extent. 

 Within the cell reaction occurs readily. This fundamental fact early 

 suggested that within the cell either oxygen or the foodstuffs have 

 become activated in some way that permits their interaction. 



During the decade 1920-30 a controversy raged between two 

 schools. One, championed by Warburg, claimed that oxygen activa- 

 tion was the all-essential mainspring. Once oxygen was activated, 

 its direct attack upon the substrate was thought possible. The other 



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