Completely Different Effects of Desferrioxamine on Hemin/Nitrite/H2O2-Induced Bovine Serum Albumin Nitration and Oxidation

Abstract

Protein tyrosine nitration is becoming increasingly recognized as a prevalent post-translational modification that could serve as a biomarker of nitric oxide (NO)-mediated oxidative stress. One received protein nitration model is the heme- or hemoprotein-dependent pathway that involves the contribution of iron and the formation of free radicals. Therefore, the iron chelating agent desferrioxamine (DFO) can affect the development of oxidative and nitrative stress. In the hemin/nitrite/H2O2 system-induced bovine serum albumin (BSA) nitration and oxidation model, BSA was analyzed for 3-nitrotyosine and carbonyl groups measured by spectrophotometry, SDS-PAGE, and Western blotting upon exposure to DFO. The results showed a significant dose-dependent inhibitory effect of DFO on BSA nitration, while an enhancement on oxidation was surprisingly observed. The promotion on protein oxidation could not be the result of the formation of ferrioxamine since the antinitration and prooxidant effect of DFO was abolished when it combined with Fe3+ to form ferrioxamine. Our studies also indicated that the abnormal effect of DFO on promoting protein oxidation probably originated from the hemin-DFO complex, which needs further study. The completely different effects of DFO on hemin-induced protein tyrosine nitration and protein oxidation should be taken into account when DFO is used in experimental and clinical applications.