CHAPTER 4 



Basic Radiation Biochemistry 



Walter M. Dale 



Christie Hospital and Holt Radium Institute, Department of Biochemistry, 



Manchester, England 



Introduction: The indirect action theory — Protection effect in solutions of two or more 

 solutes — Protection effect used for determining reactivity of solutes with radicals — Speci- 

 ficity of the reaction of radicals with one solute in relation to its structure — Deamination by 

 X rays of amino acids and related nitrogenous compounds — Liberation of hydrogen 

 sidfide from cysteine hydrochloride and from reduced glutathione. Deviation from the 

 basic type of the yield-concentration relation. Biochemical effects of alpha radiation 

 compared with those of X radiation. Indirect and direct action theory: Radiation effects 

 on biological systems — Possible modifications of radiation effects. Concluding remarks. 

 References. 



INTRODUCTION 



The purpose of this chapter on basic radiation biochemistry is to set out 

 the aims of research in this subject, the achievements obtained so far, the 

 basic ideas, the difficulties to be overcome, and the integration of results 

 of different approaches to the general problem of radiation effects. No 

 attempt will be made to present a survey of the work of all investigators 

 since this is covered in other chapters. Wherever necessary, however, 

 illustrating examples will be quoted even if this means some overlapping 

 or duplication. 



The progress and achievements of the biological and physiological 

 sciences during the last century amply justify the hypothesis that the 

 manifestations of life as observed in cells, tissues, organs, and organisms 

 are ultimately to be conceived in terms of chemical reactions, though we 

 are still far from understanding the majority of these. Since this chapter 

 deals with the basic biochemistry of radiation effect it must be borne in 

 mind that the prefix "bio" drajvs a somewhat artificial line of distinction 

 between the chemistry as we know it from laboratories and the chemistry 

 of cells and cell constituents of living matter. Such a distinctive line is, 

 however, not merely a matter of convenience but has a real significance. 

 Not only are some constituents of cells of a very special and highly 

 specific chemical composition, often unknown in their final details — e.g., 

 enzymes, antibodies, and, more generally, proteins — but the term "bio- 

 chemistry" also comprises the interaction and linkage of reactions 



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