[Isolation and several properties of purified preparations of the alkaline ribonuclease of the soluble fraction of rat cerebral hemispheres].

Preparations of alkaline ribonuclease with optimum activity at pH 7,8 have been isolated from postmitochondrial fraction of the rat brain tissue by ammonium sulfate precipitation, 0.1 HCl extraction and following ammonium sulfate fractionation. Two preparations of this enzyme have been obtained by gel filtration through Sephadex G-25 and G-75, molecular weight of one of them (the most purified preparation) being about 13000. During electrophoresis the preparations moved from anode to cathode through polyacrylamide gel at pH 3.2. Bivalent cations (Ca2+, Mg2+) activated the enzyme preparations at concentration of u.10(-3)--5.10(-3) M. The degree of purification of preparations examined was 60 and 250 respectively.