The action of X-rays upon some enzymes of the living yeast cell*

Journal/Book: Rev. Can. Biol. 11: 49: 1952 (no reprints available). 1952;

Abstract: (by invitation) Department of Pharmacology Dalhousie University Halifax *Project #5 National Cancer Institute of Canada 1. Stewart K D and J. G. Aldous Proc. Can. Physiol Soc. 1949 Abstract Suspensions of living but non-dividing cells of baker's yeast were exposed to radiation from the 2 million volt machine et Chalk River Ontario. The total dose received was approximately 72 000 r. and the viability of the population upon completion of irradiation was of the order of 40 % of a non-irradiated aliquot of the same suspension. The cells were washed dried and ground according to procedures which have been previously described (1). Various enzyme systems were then isolated from the dried material and their activities compared to extracts made from non-irradiated cells. Carboxylase hexokinase and zymase all suffered an inhibition ranging from 30 to 45 %. On the other hand catalase and alcohol dehydrogenase showed no reduction in activity. These results are qualitatively identical with those reported for the action of ultraviolet radiation (1) although the mechanisms whereby these two agents produce their biological effects believed to be quite dissimilar.

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