Protein damages in irradiated deoxyribonucleoprotein.

桑原幹典,林 正信,吉 井義一:北 海道大学獣 医学 部放射 線学 教室,札 幌市北区北18条 西9丁 目,〒060 When the solid-state deoxyribonucleoprotein (DNP) was irradiated by gamma rays, Lucke Huhle et al.1) found that single strand breaks of DNA were produced more frequently in the DNP than in pure DNA. Ormerod2) and Kuwabara and Yoshii3) reported that the ESR spectra of DNP after irradiation showed radicals to be located preferentially on the DNA moiety, and the results were explained by the electron transfer from the protein moiety to the DNA moiety. From studies on the luminescence decay curve of DNP when irradiated with electron pulses, Lillicrap and Fielden4) also found that the excitation energy formed in the protein moiety was transferred to the DNA moiety. When the DNP solution was irradiated by gamma rays, Weiss and Wheelers5) and Hayashi et al.6) found that the template activity of DNP for RNA synthesis was considerably enhanced by irradiation (10-20 krad), whereas Hagen et al.7) found that the template activity of purified DNA was markedly reduced. Using an irradiated DNP template, Mee et al.8) also reported that changes in the base composition of the synthesized RNA were found at doses of 10-20 krad.