title: The influence of antibiotics and antitumor agents on the relaxation activity of Pisum sativum leaf chloroplast topoisomerase I.
abstract: DNA topoisomerase was isolated from pea leaf chloroplasts. The relaxation activity of this topoisomerase was Mg2+ dependent and sensitive to ethidium bromide and novobiocin, a gyrase inhibitor. Chloroplast topoisomerase (Topo I) was ATP independent, as shown by the characteristic gel distribution of topoisomers. Topoisomerase, compared with the known eucaryotic topoisomerase I, was not stimulated by polyamines as are spermidine, spermine, and cadaverine. Ethidium bromide, DAPI, heparin, nalidixic acid, and m-AMSA (but not camptothecin) were able to inhibit the relaxation activity of chloroplast topo I. Nalidixic acid, novobiocin, m-AMSA, camptothecin, and amiloride were tested for their effects on the topoisomerase-catalyzed "cleavage complex" between DNA and chloroplast DNA topoisomerase I.
authors.affiliation: Institute of Cell Biology and Genetic Engineering, Academy of Sciences of the Ukraine, Kiev.
authors.forename: A M
authors.initials: AM
authors.lastname: Zagariya
authors.forename: L A
authors.initials: LA
authors.lastname: Sitailo
mesh_terms: D000584:Amiloride / Q000494:pharmacology; D000677:Amsacrine / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002166:Camptothecin / Q000494:pharmacology; D002736:Chloroplasts / Q000201:enzymology; D004264:DNA Topoisomerases, Type I / Q000378:metabolism*; D018744:DNA, Plant / Q000187:drug effects / Q000378:metabolism; D004996:Ethidium / Q000494:pharmacology; D006493:Heparin / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D008274:Magnesium / Q000494:pharmacology; D009268:Nalidixic Acid / Q000494:pharmacology; D009675:Novobiocin / Q000494:pharmacology; D018532:Pisum sativum / Q000201:enzymology; D011073:Polyamines / Q000494:pharmacology; D059004:Topoisomerase I Inhibitors
chemical_list: D000900:Anti-Bacterial Agents; D000970:Antineoplastic Agents; D018744:DNA, Plant; D007211:Indoles; D011073:Polyamines; D059004:Topoisomerase I Inhibitors; D000677:Amsacrine; D009675:Novobiocin; D009268:Nalidixic Acid; C007293:DAPI; D000584:Amiloride; D006493:Heparin; D004264:DNA Topoisomerases, Type I; D004996:Ethidium; D008274:Magnesium; D002166:Camptothecin