[Mechanism of action of DNAse from the rat brain]

The mechanism of action of exodeoxyribonuclease from rat brain predominantly localized in neuronal nuclei was studied. The enzyme which is highly specific towards one-chain DNA can effectively hydrolyze the two-chain DNA of plasmid pBR 322 "activated" by the disruption of the phosphodiester bond in one chain. A kinetic analysis of DNA hydrolysis with a tritium label evenly distributed along the DNA molecule and terminally labeled with phosphate revealed that the enzyme hydrolyzes polynucleotides from the 5'-to the 3'-end via a partially processive mechanism.