Evidence for possible positive hole transport in the biological protein bovine serum albumin

Using the pulse radiolysis technique, the oxidation of the biological protein bovine serum albumin (BSA) by the species N₃^., CCl₃O₂^., OH and Br₂^.– has been studied in aqueous solution. The repair of the N₃^. oxidation by ascorbic acid and the effect of denaturing the protein on this repair has also been studied. The oxidation of Br₂^.– 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 Br₂^– and N₃^. 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.