The Separation of two Deoxyribonucleases from Extracts of Intestinal Mucosa of the Rat

Abstract

Two deoxyribonucleases have been demonstrated in cell-free extracts of rat intestinal mucosa. The enzymes were separated by ion-exchange chromatography on DEAE-cellulose and further purified by partition on hydroxyapatite. One DNase had optimum activity at pH 6.8–7.0 in ammonium acetate buffer, required Mn2+ or Mg2+ for activity, and was inhibited by EDTA. This enzyme is a DNase I by Laskowski's criteria Advan. Enzymol. 29, 165 (1967). The second enzyme was a DNase II with optimum activity at pH 3.5–4.0 in sodium formate buffer, was not inhibited by EDTA, and showed no requirement for divalent cations. Both enzymes were active only with native DNA and had no action on heated DNA or purified yeast transfer RNA.