title: Mitochondria contain a distinct DNA topoisomerase.
abstract: A topoisomerase (nicking-closing enzyme) has been isolated from rat liver mitochondria. It has purified by double-stranded DNA-cellulose chromatography approximately 50,000-fold, based on the crude mitochondrial extract. It possesses a minimum specific activity of 1.9 x 10(5) units/mg. The enzyme has been shown to be distinctly mitochondrial, differentiated from the nuclear topoisomerase by its sensitivity to the intercalating drug, ethidium bromide, and to the non-intercalating trypanocidal drug, Berenil.
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000201:enzymology; D002846:Chromatography, Affinity; D004264:DNA Topoisomerases, Type I / Q000302:isolation & purification* / Q000378:metabolism; D004278:DNA, Superhelical; D004133:Diminazene / Q000494:pharmacology; D004996:Ethidium / Q000494:pharmacology; D008099:Liver / Q000201:enzymology; D008297:Male; D008930:Mitochondria, Liver / Q000201:enzymology*; D051381:Rats
chemical_list: D004278:DNA, Superhelical; D004264:DNA Topoisomerases, Type I; D004996:Ethidium; D004133:Diminazene