Polyamine-dependent Deoxyribonuclease Activity from Rat-Liver Nuclei

Abstract

When nuclei isolated from rat liver in a low salt buffer were washed with 0.1 M NaCl solution, the supernatant showed a deoxyribonuclease (DNase) activity. The activity required Mg²⁺ and in addition spermine or spermidine, and its optimal pH was 7.2-7.4. The activity was higher on denatured (single stranded) DNA than on double-helical DNA. With both sub-strates the activity was highest at a polyamine concentration at which the DNA-polyamine complex began to precipitate. No Mg²⁺+Ca²⁺ dependent DNase activity was detected in the preparation.