title: Molecular basis of the antineoplastic activity of 3'-amino-3'-deoxythymidine.
abstract: 3'-Amino-3'-deoxythymidine decreased the incorporation of [2-14C]thymidine into DNA of L1210 cells in vitro, and produced an accumulation of [2-14C]thymidine di- and triphosphate. The extent of these effects varied with the amount of recovery time after removal of 3'-amino-3'-deoxythymidine prior to addition of labeled thymidine. The distribution of radioactivity in the acid-soluble fraction derived from [3H]3'-amino-3'-deoxythymidine was as follows: 50% as 3'-amino-3'-deoxythymidine, 20% as the monophosphate, 10% as the diphosphate, and 20% as the triphosphate derivatives. No incorporation of [3H]3'-amino-3'-deoxythymidine into L1210 DNA could be detected. 3'-Amino-3'-deoxythymidine-5'-triphosphate is a competitive inhibitor against dTTP with a Ki of 3.3 microM, whereas the Km for dTTP was 8 microM using activated calf thymus DNA as the template and DNA polymerase-alpha. These data indicate that a major site of inhibition by 3'-amino-3'-deoxythymidine is inhibition of the DNA polymerase reaction.
mesh_terms: D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000633:toxicity*; D004257:DNA Polymerase II / Q000037:antagonists & inhibitors; D004261:DNA Replication / Q000187:drug effects*; D015224:Dideoxynucleosides; D007700:Kinetics; D007939:Leukemia L1210 / Q000188:drug therapy* / Q000378:metabolism; D051379:Mice; D013936:Thymidine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000633:toxicity
chemical_list: D000964:Antimetabolites, Antineoplastic; D015224:Dideoxynucleosides; C024082:5'-amino-5'-deoxythymidine; D004257:DNA Polymerase II; D013936:Thymidine