Effect of X-Irradiation on the Absorption Spectrum of Purines and Pyrimidines

Publisher Website
Google Scholar
Abstract
X-irradiation of aqueous dilute solutions of deoxyribonucleate, ribonucleate, and a number of purines and pyrimidines decreased the UV absorption at 2600 A, the decrease being proportional to X-ray dose in all cases. The effect was more pronounced in the simple purine and pyri-midine compounds; as the molecule became more complex on addition of other groups, such as pentose and phosphoric acid residues, it became more resistant to the action of ionizing radiations. The decrease in the absorption spectrum was greater on irradiation in the presence of 02 than on irradiation in the presence of N. Reduced diphosphopyridine nucleotide was readily oxidized by X-irradiation; oxidation was more effective on irradiation in O2 than on irradiation in N. Pyridine nucleotide reduced by X-irradiation in the absence of N and in the presence of lactate or alcohol was reduced to a compound which was partially active enzymatically.