Synthesis, properties and use of beta-alanyltyrosine derivatives of 2',5'-oligoadenylate 5'-triphosphate

beta-Alanyltyrosine methyl ester derivatives of 2-5 A, ppp-(A2'p5') A-beta-Ala-Tyr, were prepared by coupling of periodate oxidizedn2-5 A with beta-alanyltyrosine methyl ester, followed by reduction with sodium cyanoborohydride. The compounds were resistant to the hydrolysis by 2',5'-phosphodiesterase in the mouse L cells extract. They bound to the 2-5 A dependent RNAse (RNAse L) in the mouse L cells extract and in the rabbit reticulocyte lysate, and displaced by addition of 2-5 A. The compound, pppA2'p5'A2'p5'A2'p5'A-beta-Ala-Tyr, after iodination with 125I, was proved to be useful as a radio-labeled probe for the radiobinding assay for 2-5 A.