[Activity of ribonuclease in Acetabularia]

In Acetabularia mediterranea, Acetabularia crenulata and Polyphysa cliftonii ribonuclease activity was demonstrated. The enzyme is heat stabile and exhibits maxima at pH 7.2 and at the region of pH 5. Even centrifugation with 100000 x g for 120 minutes does not result in sedimentation of enzyme activity.Anucleate cells of Acetabularia are capable of increasing their ribonuclease activity, but to a smaller extent than nucleate cells do.The stability of the genetic information in the cytoplasm of anucleate Acetabularia cannot be explained by a lack in ribonuclease activity.