[Specificity of the degradation and synthesis of dinucleoside monophosphates by RNAase C2 of Asp. clavatus].

The ability of RNAase E2 to degradate dinucleoside moniphosphates and to form internucleotide bonds was studied. The compounds of the GpN type were found to be a good substrate for RNase C2. The pH optimum for GpC was 5.5 (acetate buffer) and the temperature optimum was 30 degrees C. The values of Km and Vmax on GpC, GpA, GpG and GpU were determined. The affinity of the substrates for the enzyme decreased in the sequence GpC greater than GpG greater than GpA GREATER THAN GpU. RNase C2 catalyze the synthesis of GpC and GpU. The yield of GpC amounted to 60% and that of GpU was 35%. These data indicate that RNase C2 FROM Asp. clavatum is guanyl ribonuclease (EC 3.1.4.8.).