Deoxyribosyl compounds in animal tissues.

Several types of deoxyribosyl compounds have been found in the acidsoluble fraction of normal and malignant tissues (l-8). In 1955 Potter and Schlesinger (1) reported the isolation of deoxynucleoside mono-, di-, and triphosphates from extracts of calf thymus. More recently LePage (7) reported the isolation of deoxyadenosine triphosphate from a tumor. Schneider (2), using a microbiological assay method, found that small amounts of deoxyribosyl compounds were present in the blood and in all of the tissues of the rat and mouse which were examined. Studies on the isolation of the deoxyribosyl compounds of rat liver and blood indicated that deoxycytidine accounted for almost the entire microbiological activity of the tissue extracts (2, 3). Extracts of the Novikoff hepatoma and of regenerating liver, however, contained considerable proportions of deoxynucleotide-like material (3, 4). Studies of the growth requirements of the organism used in the assay method (Lactobacillus acidophilus R-26) had indicated that equivalent growth was obtained with equimolar amounts of any of the natural deoxynucleosides or nucleoside monophosphates (2, 9, 10). Growth was also supported by dideoxynucleotides but not by deoxynucleoside dior triphosphates (9). The present study was undertaken to develop methods whereby compounds of the latter type could be measured microbiologically. The following report describes methods for the enzymatic conversion of these compounds to nucleosides or nucleoside monophosphates and presents the results of simultaneous determinations of the content of deoxynucleosides, deoxynucleoside monophosphates, and “digestible” deoxynucleotides for various rat and mouse tissues. Those compounds which required enzymatic digestion for conversion to nucleosides or nucleoside monophosphates are designated as “digestible” nucleotides in this report.