Change in the enzymatic dual function of the peroxiredoxin protein by gamma irradiation

PP1084 protein was exposed to gamma irradiation ranging from 5 to 500kGy. Native PAGE showed minor structural changes in PP1084 at 5kGy, and major structural changes at >15kGy. Size-exclusion chromatography (SEC) showed the formation of a new shoulder peak when the protein was irradiated with 15 and 30kGy, and a double peak appeared at 100kGy. The results of PAGE and SEC imply that PP1084 protein is degraded by gamma irradiation, with simultaneous oligomerization. PP1084 chaperone activity reached the highest level at 30kGy of gamma irradiation, and then, decreased in a dose-dependent manner with increasing gamma irradiation. However, the peroxidase activity significantly decreased following exposure to all intensities of gamma irradiation. The improvement of chaperone activity using gamma irradiation might be promoted by the oligomeric structures containing covalently cross-linked amino acids. Consequently, PP1084 modification using gamma irradiation could elevate chaperone activity by about 3–4 folds compared to the non-irradiated protein.