The dissection of oxidative changes in human blood serum and U937 cells exposed to free radicals

Abstract

It is well established that the lipids in human blood plasma or serum, exposed to peroxyl free radicals, become oxidized after a lag period, during which plasma ascorbate is completely depleted.¹ In contrast, the fate of proteins in oxidatively stressed plasma has been less thoroughly investigated, although they are likely to be an early significant target for radicals. In this study, we addressed the possibility of the generation of protein hydroperoxides in human blood serum and in the U937 human cell line. Formation of protein hydroperoxide and carbonyl groups in serum subjected to radiation-generated hydroxyl radicals occurred before any detectable oxidation of the lipids. Similar results were obtained with the U937 cells exposed to a flux of peroxyl radicals.