Formation of a New Type of Dinitrosyl Iron Complexes Bound to Cysteine Modified with Methylglyoxal

摘要

It has been shown that interaction of cysteine dinitrosyl iron complexes with methylglyoxal leads to the formation of a new type of dinitrosyl iron complexes, EPR spectrum of these complexes essentially dif- fers from spectra of dinitrosyl iron complexes containing unmodified thiol. The products of the cysteine reac- tion with methylglyoxal are hemithioacetals, Schiff bases and thiazolidines, which most likely serve as ligands for the new type of dinitrosyl iron complexes. It has been shown that the new type of dinitrosyl iron complexes as cysteine dinitrosyl iron complexes, which are physiological donors of nitric oxide, exert a vasodilator effect. It has also been found that the oxidative destruction of the new type of dinitrosyl iron complexes occurs at normal oxygen partial pressure, but these dinitrosyl iron complexes remain rather stable under hypoxia mod- eling. An assumption that the destruction of the new type of dinitrosyl iron complexes is caused by the for- mation of a bound peroxynitrite-containing intermediate is made.