Effects of the Cobalt-60 gamma radiation on glyceraldehyde-3-phosphate dehydrogenase.

Purpose: Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a key enzyme of the glycolytic pathway, can play a physiological regulatory role and vital other roles in metabolism. This study investigated the effects of gamma radiation generated by Cobalt-60 source on GAPDH activity and protein levels in as an eukaryotic organism model.

Materials And Methods: After purification of the GAPDH from , in vitro effects of irradiation to the dose of 2 Gy, using Cobalt-60 at the dose rate of 0.25 Gy/min, on activity and kinetic parameters were investigated. In vivo effects of gamma exposition (dose of 5 Gy) on GAPDH and on reactive oxygen species (ROS) markers were also explored.

Results And Conclusions: The in vitro irradiation of the purified GAPDH reduces the specific activity and the maximum velocity () without alteration of substrates binding (). No changes occurred in the specific activity and in kinetic parameters when cells were exposed to Cobalt-60 source. However, this in vivo irradiation of cells produced a significant increase of the GAPDH protein level. The changes of GAPDH activity and the increase of the enzyme population as a target for gamma radiation exposure will play a role in cells adaptation under stress conditions. On the other hand, the increase of malondialdehyde and carbonyl contents and the enhancement of catalase and superoxide dismutase in irradiated cells have been noticed. The antioxidant system can play an important role in the protection of GAPDH against the gamma induced-ROS damage. This is the first report of the GAPDH as a physiological target of gamma exposition.