title: The effect of hydroxycamptothecin in the activity of RNA and DNA polymerases prepared from murine hepatoma cells.
abstract: Hydroxycamptothecin (HCPT) is an antitumor alkaloid isolated from Camptotheca acuminata indigenous to China. It could reduce the activity of nuclear RNA polymerase II and I(III) of hepatoma cells. HCPT at 25-100 microM caused a remarkable inhibition on DNA polymerase alpha whilst only a slight inhibition on beta. The inhibitory action on alpha was restored by increasing amounts of enzyme or DNA template, but unchanged by varying amounts of substrate. It is suggested that HCPT may exert a stronger inhibition on DNA replication process.
mesh_terms: D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002467:Cell Nucleus / Q000201:enzymology; D004256:DNA Polymerase I / Q000037:antagonists & inhibitors; D004257:DNA Polymerase II / Q000037:antagonists & inhibitors; D004261:DNA Replication / Q000187:drug effects; D012321:DNA-Directed RNA Polymerases / Q000037:antagonists & inhibitors*; D066298:In Vitro Techniques; D008114:Liver Neoplasms, Experimental / Q000188:drug therapy* / Q000201:enzymology; D051379:Mice; D019384:Nucleic Acid Synthesis Inhibitors
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D019384:Nucleic Acid Synthesis Inhibitors; C028098:10-hydroxycamptothecin; D012321:DNA-Directed RNA Polymerases; D004256:DNA Polymerase I; D004257:DNA Polymerase II; D002166:Camptothecin