RADIOLYSIS OF POLYURIDYLIC ACID IN AQUEOUS-SOLUTIONS SATURATED WITH N2O

Radiation-chemical yields of formation for 5-hydroxydihydrouracil and uracil and a radiation-chemical yield of decomposition for polyuridyli c acid [poly(U)] upon its radiolysis in N2O-saturated aqueous solution s are 0.4, 3.1, and 4.4 molecule/100 eV, respectively. Measurement of the 5-hydroxydihydrouracil yield upon radiolysis of poly(U) in the pre sence of cysteamine demonstrated that only 20% of OH radicals that att ack poly(U) give rise to C(5) OH adducts of uracil. It was suggested t hat the reaction between OH and poly(U) results in unidentified reduci ng radicals along with the well-known C(5) OH and H adducts of uracil and radicals at the ribose moiety of poly(U) molecules.