Effect of massive X-irradiation on proteins and protein synthesis in peanut cotyledons

Abstract

Peanut seeds were irradiated with 500 kR of X rays and stored for 6 weeks. The cotyledons from 3-day-old seedlings were harvested, and incubated with leucine-14C. The water-soluble protein content of those cotyledons was half to one-third that of the non-irradiated cotyledons. Protein biosynthesis in the irradiated cotyledons was equally reduced to one-third or less of control. Separation of the extracted proteins by acrylamide-gel electrophoresis suggested that there may be a larger amount of small-molecular proteins in the irradiated system. De novo biosynthesis after irradiation was restricted in all protein fractions. Enzyme activity was also severely restricted. No particular radiation-resistant isoenzyme of peroxidase could be detected.