title: DNA topoisomerase I from human placenta.
abstract: In this study we report that human placenta is an excellent source of DNA topoisomerase I. The enzyme can be isolated in the fully intact 100 kDa form although lower molecular mass species are also observed. Occasionally, the enzyme can be resolved into two peaks of activity by chromatography on phosphocellulose. As expected, the enzyme promotes marked cleavage of DNA in response to the anticancer drug camptothecin. Because of this property and the ready availability of human placenta, the enzyme should prove to be useful in the development and testing of new anticancer drugs that target topoisomerase I.
authors.affiliation: Department of Pathology, University of Utah, Salt Lake City.
authors.forename: J A
authors.initials: JA
authors.lastname: Holden
authors.forename: D H
authors.initials: DH
authors.lastname: Rolfson
authors.forename: R L
authors.initials: RL
authors.lastname: Low
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D002166:Camptothecin / Q000494:pharmacology; D002845:Chromatography; D004247:DNA / Q000378:metabolism; D004264:DNA Topoisomerases, Type I / Q000302:isolation & purification / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D010710:Phosphates / Q000378:metabolism; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy
chemical_list: D010710:Phosphates; D000255:Adenosine Triphosphate; D004247:DNA; D004264:DNA Topoisomerases, Type I; D002166:Camptothecin