Disturbances in DNA precursor metabolism associated with exposure to an inhibitor of poly(ADP-ribose) synthetase.
3-Aminobenzamide (3AB) is widely used as an inhibitor of poly(ADP-ribose) synthetase to study the effect of protein ribosylation on various cellular processes, but the specificity of its inhibition has not been demonstrated. We found that 3AB has a wide range of effects on DNA precursor metabolism, as determined by high-performance liquid chromatographic separation of deoxynucleosides derived from enzymatic digestion of cellular DNA. 3AB (10-20 mM) significantly reduced cell growth in human lymphoblastoid cells. Furthermore, the incorporation of [3H]deoxycytidine into DNA was significantly enhanced relative to incorporation of [3H]deoxythymidine, [3H]deoxyguanosine, and [3H]deoxyadenosine. Incorporation of fragments of [3H]glucose into the pyrimidine fraction of DNA was significantly inhibited relative to incorporation into the purine fraction. At only 1 mM, 3AB had a major inhibitory effect on the incorporation of the methyl group from [3H]methionine into deoxyguanosine, deoxyadenosine, and deoxycytidine, with 50% inhibition into deoxyguanosine and deoxyadenosine and 90% inhibition into deoxycytidine. The specificity of 3AB inhibition to poly(ADP-ribose) synthetase is therefore doubtful in view of this variety of metabolic effects, involving pyrimidine synthesis and de novo synthesis via the one-carbon pool.
D001549:Benzamides / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000096:biosynthesis; D003839:Deoxyadenosines / Q000378:metabolism; D003841:Deoxycytidine / Q000378:metabolism; D003849:Deoxyguanosine / Q000378:metabolism; D006801:Humans; D009705:Nucleosides / Q000378:metabolism*; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D013936:Thymidine / Q000378:metabolism
D001549:Benzamides; D003839:Deoxyadenosines; D009705:Nucleosides; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D003841:Deoxycytidine; C025160:3-aminobenzamide; D004247:DNA; D003849:Deoxyguanosine; D013936:Thymidine