PROTEIN THIYL FREE-RADICALS PRODUCED BY NITRIC-OXIDE AND NITRIC-OXIDEDONORS

The spin-trapping technique was used to study the radical intermediate s produced by reaction of nitric oxide (TNO) and peroxynitrite with se rum albumin and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Our results show that the major radical product induced by (NO)-N-. and by peroxynitrite with serum albumin and GAPDH was a thiyl radical. The s ame radical can be detected in the (NO)-N-.-transfer from S-nitroso al bumin to low molecular weight thiols. Moreover, (NO)-N-. or peroxynitr ite treatment of GAPDH was able to induce NAD-dependent covalent modif ication of the enzyme in erythrocyte ghosts.