title: DNA topoisomerase I from Alcaligenes eutrophus H16.
abstract: Molecular and functional properties of DNA topoisomerase I isolated from a hydrogen-oxidizing bacterium, Alcaligenes eutrophus H16, were investigated. Under native conditions the enzyme forms a monomer with a relative molar mass of 98,500. A rod-like shape of the molecule was derived from the calculated frictional coefficient. The isoelectric point of the enzyme was determined to be in the range of 7.6-8.0. The enzyme activity is strictly Mg2+ dependent with an optimum at 3 mM Mg2+. The pH optimum ranges within 7.5-9.0. A. eutrophus DNA topoisomerase I activity is inhibited by M13 ssDNA, high ionic strength, polyamines, heparin and by a number of intercalating drugs.
authors.affiliation: Institute of Microbiology, Czechoslovak Academy of Sciences, Prague.
authors.forename: L
authors.initials: L
authors.lastname: Andĕra
authors.forename: K
authors.initials: K
authors.lastname: Mikulík
mesh_terms: D000421:Alcaligenes / Q000201:enzymology*; D004264:DNA Topoisomerases, Type I / Q000302:isolation & purification / Q000378:metabolism*; D004269:DNA, Bacterial / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D008274:Magnesium / Q000494:pharmacology; D008970:Molecular Weight; D010957:Plasmids; D011189:Potassium Chloride / Q000494:pharmacology; D059004:Topoisomerase I Inhibitors
chemical_list: D004269:DNA, Bacterial; D059004:Topoisomerase I Inhibitors; D011189:Potassium Chloride; D004264:DNA Topoisomerases, Type I; D008274:Magnesium