Using the pulse radiolysis technique, the oxidation of the biological protein bovine serum albumin (BSA) by the species N
, OH and Br
has been studied in aqueous solution. The repair of the N
oxidation by ascorbic acid and the effect of denaturing the protein on this repair has also been studied. The oxidation of Br
seems to follow a different course from that of the other oxidizing agents suggesting the possibility of positive hole mobility in this protein. The repair by ascorbic acid is found more effective in the case of denatured protein. The rate constants for the reaction of Br
are lower, in general, in the case of the denatured protein as compared with the undenatured BSA both at pH 6.9 and pH 10.7, suggesting that the convoluted structure of the protein plays a part in the process.