抄録
Polyadenylic acid was depolymerized with relatively high concentration of RNase-A to oligoadenylic acids having 2', 3'-cyclic phos-phoryl groups as terminal nucleotides and denosine 2', 3'-cyclic phosphate. The latter was further hydrolyzed very slowly to adeno-sine 3'-phosphate.
The mode of liberation of the intermediates and the final product was compared with that in the case of poly U with ordinally concen-tration of the same enzyme. Effects of pH and salt concentration and influence of specific carboxymethylation of the enzyme on the reaction rates were compared when poly A and RNA were used as substrates.
The results indicated that both poly A and natural substrate should be degraded by RNase with the similar mode of reaction. The quantitative estimation of reaction rates of RNase against poly A, poly U, A-cyclic-p and U-cyclic-p was performed and the interactions of poly A with the enzyme were discussed.
The authors gratefully indepted to Takeda Chemi-cal Industries Ltd. for the kind supply of the nucleo-tides used. Thanks are also due to Dr. H. Hayatsu of our faculty for his valuable discussions in this research.
