ELECTRON SPIN RESONANCE (ESR) INVESTIGA- 

 TIONS ON RADIATION-INDUCED CHEMICAL EFFECTS 



IN BIOLOGICAL SPECIES 



L. A. BLUMENFELD AND A. E. KALMANSON 



Institute of Chemical Physics, U.8.S.R. Academy of Science, 



Moscow, U.S.S.R. 



SUMMARY 



The ESR method may be used to investigate radiation-produced unpaired 

 electrons in lyophilized biological structures. The authors have studied nearly 

 all the amino acids, a number of di- and tripeptides and various proteins, nucleo- 

 proteins and tissvies. 



The number of free radicals produced in y-irradiated lyophilized proteins is 

 some two or three orders of magnitude less than in amino acids and peptides. 

 It is suggested that "conductive channels" may exist and that electrons can 

 migrate along these, thus "healing" the injuries. 



The appearance of a new method of investigation, especially if based 

 on exact theory, often leads to considerable progress. This is exactly so 

 in the case of the ESR method, which was invented by the Soviet 

 physicist, Zavoysky, in 1944. 



There are a number of articles on the theory of ESR and its experi- 

 mental techniques (Frenkel, 1954; Gordy, et al., 1955; Ingram, 1955, 

 1958; Van Vleck, 1948; Semenov and Bubnov, 1959). These problems 

 will not, therefore, be discussed. 



It is known that the ESR method permits us to obtain the following 

 information about the substances investigated ; 



1. The presence of unpaired electrons at concentrations of about 

 10-11 to 5 X 10-12JVI per gram, or, in other words, IO12 to IQi^ unpaired 

 electrons in the sample ; 



2. A sufficiently correct quantitative estimation of the concentration 

 of unpaired electrons (by comparison with standards) ; 



3. The analysis of the form and the width of ESR spectral lines 

 permits important conclusions to be drawn about the interaction be- 

 tween unpaired electrons and the surrounding atoms ; the influence of 

 structural particularities of the substance being investigated on the 



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