Radiation-induced reduction reactions with bovine serum albumin.

The reduction of bovine serum albumin (BSA) by hydrated electrons, formate and ethanol radicals leads to the formation of S-S-radicals. The reaction of the hydrated electrons becomes faster, if BSA was preirradiated in the presence of formate or ethanol, but the rate does not change if radiolysis is done in the presence of t-butanol or without scavenger. The reduction of BSA by formate radicals is 10 times slower but gives a higher yield of S-S-radicals than by hydrated electrons. The rate and yield of the reduction by the formate radicals are increased by preirradiation of BSA. The reduction by ethanol radicals is five times slower than by formate radicals and gives lower yields of S-S-radicals which are increased by preirradiation. All rates and yields of the reduction reactions are decreased by changing the pH from 6.3 to 7.3.