Analogs of 2′-deoxyadenosine: Facile enzymatic preparation and growth inhibitory effects on human cell lines

Abstract

Nucleoside deoxyribosyltransferase has been extensively purified from extracts of Lactobacillus leichmannii. The enzyme was initially co-purified with ribonucleotide reductase and then separated from the latter by affinity chromatography on dGTP-Sepharose. A new procedure is described for the synthesis of 6-( p-aminobenzylamino)purine. The latter was diazotized and reacted with Sepharose substituted with m-phenylenediamine to produce an affinity material for chromatography of the transferase. Some properties of the purified transferase are described, including remarkable stability to heat and to guanidine hydrochloride. With thymidine as donor, the transferase had a very broad specificity for the purine acceptor, the only modifications not tolerated being the loss of the tautomeric N in the imidazole ring and, possibly, substitution at the 8-position. The enzyme was used for the convenient synthesis of twelve analogs of 2'-deoxyadenosine on the 100–400 mg scale with an average yield of 64 per cent. The method was readily applicable to larger scale preparations and the enzyme was recoverable from the final reaction mixtures in good yield. Of the nucleosides synthesized, the 2-chloro and 2-bromo analogs of 2'-deoxyadenosine were especially good inhibitors of the growth of KB and CCRF-CEM cells in culture.