PROTECTION AGAINST PEROXYNITRITE-DEPENDENT TYROSINE NITRATION AND ALPHA(1)-ANTIPROTEINASE INACTIVATION BY OXIDIZED AND REDUCED LIPOIC ACID

Peroxynitrite, formed by combination of superoxide radical with nitric oxide, is a reactive tissue-damaging species apparently involved in t he pathology of several human diseases. Peroxynitrite nitrates tyrosin e residues and inactivates alpha(1)-antiproteinase, We show that both lipoic acid and dihydrolipoic acid efficiently protect against damage by peroxynitrite, By contrast, other disulphides tested did not, The b iological antioxidant effects of lipoate/dihydrolipoate may involve sc avenging of reactive nitrogen species as well as reactive oxygen speci es.