1160 BIOLOGICAL EFFECTS OF RADIATION 



lost within 1 hr. after irradiation. Pancreatin activity is also attenuated 

 by the action of ultra-violet radiation (Pincussen and Klissimus, 67^); 

 but this enzyme is much more light-resistant in the presence of salts of 

 iodine (other salts are less active). 



A few other qualitative studies on miscellaneous enzymes may be 

 mentioned. Emulsin, milk aldehydrase, and succino-dehydrogenase 

 each suffered partial inactivation upon irradiation with ultra-violet from 

 a mercury-vapor arc. The destruction of activity of emulsin was found 

 by Helferich and Brieger (33) to be differential, depending upon whether 

 emulsin is tested against ^-d glucoside or a-d mannoside. Pincussen and 

 Oya (67n, 67o) found inactivation of milk aldehydrase by ultra-violet 

 in the presence of oxygen at the optimal pH of 7.35, while Pincussen and 

 Roman (67g) reported that an irradiation of 15 min. injured succino- 

 dehydrogenase of horse muscle to the same extent as irradiation of 1 hr. 

 with visible light. 



The above review attempts to describe representative work on the 

 effects of radiation on enzymes, giving consideration, where possible, to 

 the several groups of enzymes and to the historical aspect. There are, 

 unfortunately, very few articles, which, while presenting a systematic 

 study of the effects of radiation on enzymes, at the same time take 

 advantage of the modern developments in radiation technique and of the 

 best methods of enzyme purification. The value of future work in this 

 field will be enhanced by consideration of these advances and by giving 

 strict attention to all conditions or modifying factors. 



REFERENCES 



1. Agulhon, H. Action des rayon.s ultraviolets sur les diastase.s. Compt. Rend. 

 Acad. Sci. [Paris] 152 : 398-401. 1911. '{See aho Ibid, (a) 153 : 979-982. 191 1.) 



2. Agulhon, H. Action de la lumiere sur les diastases. Ann. Inst. Pasteur 26: 

 38-47. 1912. 



3. Alverseng, J. P., L. Jaloustre, and E. Maurin. Sur quelques actions du 

 thorium .sur les dia.stases et les microbes. Compt. Rend. Acad. Sci. [Paris] 

 176:193-195. 1923. 



4. Bach, A. tJber das Verhalten der Peroxidase gegen Licht. Ber. deut. chem. 

 Ges. 41: (1): 225. 1908. 



5. Batelli, F., and L. Stern. Action de la lumi&re sur la catala.se. Compt. 

 Rend. Soc. Biol. [Paris] 68: 1040. 1910. 



6. Bergell, p., and A. Braunsteix. Ucber den Einfluss der Radium.salzc auf den 

 fermentativen Ei\veis.sabbau. Med. Klin. 1: 310-314. 1905. 



7. Bering, F., and H. Meyer. Experimentelle Studien iiber die Wirkung des 

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 der verschiedenen Strahlengruppen und ihre Sensibilisierung. Strahlentherapie 

 1:411-437. 1912. 



8. BiCKEL, A., and D. Minami. Ueber die biologische Wirkung des Mesothoriums. 

 I. Ber. Klin. Wochen.sch. 48: 1413. 1911. 



9. Brown, F. R. The influence of radium and of its decomposition products on the 

 ferments. Arch. Internat. Med. 10: 405-413. 1912. 



