Molecular Pharmacology, Vol 3, 37-43, Copyright © 1967 by the American Society for Pharmacology and Experimental Therapeutics

The Utilization of -2'-Deoxythioguanosine by Murine Tumor Cells

¹ Life Sciences Research, Stanford Research Institute, Menlo Park, California 94025

The - and -anomers of 2'-deoxythioguanosine were prepared with a radiocarbon label in the sugar moiety and a radiosulfur label in the base. In vivo experiments were conducted with Mecca Lymphosarcoma ascites cells in mice. Determination of the distribution of radioactivity in base and sugar of material incorporated into deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), relative to the distribution in the precursors, indicated that both anomers can be incorporated into the DNA without the separation of sugar and base. Degradation of DNA containing label from these nucleotide precursors, with deoxyribonuclease and phosphodiesterase, showed that the -anomer was almost all present in the nucleotide chain. The incorporation of -anomer into DNA gave a much higher proportion of terminal labeling, but also indicated that some -nucleoside had entered the nucleotide chain. The data also indicated that entry of -deoxynucleoside into the RNA can occur without exchange of the sugar.

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ACKNOWLEDGMENT This work was supported by Contract PH 43-65-575 with the Cancer Chemotherapy National Service Center, National Cancer Institute, National Institutes of Health.