Purification and enzymological characterization of DNA-dependent ATPase IV from the Novikoff hepatoma.
DNA-dependent ATPase IV has been purified to near homogeneity from the Novikoff rat hepatoma. The enzyme is devoid of DNA polymerase, RNA polymerase, exonuclease, endonuclease, phosphomonoesterase, 3'- or 5'-phosphodiesterase, polynucleotide kinase, protein kinase, topoisomerase, helicase or DNA reannealing activities at a detection level of 10(-5) to 10(-7) relative to the ATPase activity. The enzyme is a monomer of Mr 110,000, has a sedimentation coefficient of 5.9 S, a Stokes radius of 40 A and a frictional coefficient of 1.32. In the presence of Mg2+ ion and a polynucleotide effector, ATPase IV hydrolyzes either ATP or dATP to the nucleoside diphosphate plus Pi. Other ribo- or deoxyribonucleoside triphosphates are not substrates. ATPase IV utilizes double-stranded DNA and single-stranded DNA as effector; however, it does not utilize poly(dT). The Km for dsDNA or ssDNA is 2.2 microM (nucleotide). A variety of ATP analogues were found to be competitive inhibitors of ATPase IV.
Thomas
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Department of Biological Sciences, University of Cincinnati, OH 45221.
Rein
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Meyer
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D000227:Adenine Nucleotides / Q000494:pharmacology; D000251:Adenosine Triphosphatases / Q000302:isolation & purification* / Q000378:metabolism; D000818:Animals; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002845:Chromatography; D004247:DNA / Q000378:metabolism; D004265:DNA Helicases; D004268:DNA-Binding Proteins / Q000502:physiology; D004591:Electrophoresis, Polyacrylamide Gel; D008114:Liver Neoplasms, Experimental / Q000201:enzymology*; D051381:Rats
D000227:Adenine Nucleotides; D004268:DNA-Binding Proteins; D004247:DNA; D000251:Adenosine Triphosphatases; D004265:DNA Helicases