title: Inhibition of terminal deoxynucleotidyltransferase by various diadenosine polyphosphates.
abstract: Terminal deoxynucleotidyltransferase (TdT) was found to be strongly inhibited by diadenosine 5',5"'-P1,P4-tetraphosphate (AP4A) while other mammalian DNA polymerases alpha, beta and gamma were neither inhibited nor activated by AP4A. Such inhibitory effect on TdT was also observed with a variety of diadenosine polyphosphates (APnA), n = 3-6) when TdT activity was assayed by determining incorporation of dCTP. Kinetic analysis revealed that the inhibition of TdT by APnA was due to competition with substrate deoxynucleoside triphosphate(s).
mesh_terms: D000227:Adenine Nucleotides / Q000494:pharmacology*; D000818:Animals; D002460:Cell Line; D004253:DNA Nucleotidylexotransferase / Q000037:antagonists & inhibitors*; D004254:DNA Nucleotidyltransferases / Q000037:antagonists & inhibitors*; D004256:DNA Polymerase I / Q000378:metabolism; D004257:DNA Polymerase II / Q000378:metabolism; D004258:DNA Polymerase III / Q000378:metabolism; D015226:Dinucleoside Phosphates; D007700:Kinetics; D051379:Mice; D010954:Plasmacytoma; D013329:Structure-Activity Relationship
chemical_list: D000227:Adenine Nucleotides; D015226:Dinucleoside Phosphates; C020733:diadenosine tetraphosphate; D004254:DNA Nucleotidyltransferases; D004253:DNA Nucleotidylexotransferase; D004256:DNA Polymerase I; D004257:DNA Polymerase II; D004258:DNA Polymerase III