Purification and properties of a new DNase activity from KB cells

Gerald D. Frenkel, Karen Randies, Neil Berns

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A deoxyribonuclease activity with specificity towards single-stranded DNA has been purified approximately four hundred-fold from KB cells, by chromatography on DEAE-cellulose, phosphocellulose and hydroxylapatite. The last step of the purification results in separation of the enzyme from a DNase activity which has been described previously (Wang, E.C., Furth, J.J. and Rose, J.A., (1978) Biochemistry 17: 544-549). The properties of the new DNase activity are significantly different from those of the enzymes which have previously been identified in these cells. The activity sediments at approximately 7.5S in a glycerol gradient. The DNase activity is optimal at pHs between 6.0 and 6.5. It cleaves DNA endonucleolytically and hydrolyzes single-stranded DNA at about 11 times the rate of double-stranded DNA and at twice the rate of Poly (dA). The activity is moderately sensitive to inhibition by N-ethylmaleimide and is inhibited 80% by 50 mM NaCl. It is stimulated twenty-fold by Mn++ at an optimal concentration of approximately 0.7 mM. It is stimulated to a lesser extent by Mg++, but not by Ca++.

Original languageEnglish (US)
Pages (from-to)6635-6644
Number of pages10
JournalNucleic acids research
Issue number23
StatePublished - Dec 11 1981
Externally publishedYes

ASJC Scopus subject areas

  • Genetics


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