Peroxynitrite-generating species: Good candidate oxidants in aqueous extracts of cigarette smoke

Cigarette smoking is a well-known risk factor for atherosclerosis, but the mechanism of the adverse biological effect of smoking remains to be establi shed. Cigarette smoke contains high concentrations of free radicals and oxi dants. We show here that cigarette smoke extracts (CSE), prepared by bubbli ng the gas phase of smoke into phosphate-buffered saline, could convert tyr osine to 3-nitrotyrosine. The tyrosine nitration terminated 6 h after incub ating tyrosine with CSE at 37 degrees C. These results indicate that the ac tive oxidants in CSE are peroxynitrite-generating species like 3-morpholino sydnonimine (SIN-1), suggesting that they modify plasma lipoproteins and co ntribute to the pathogenesis of atherosclerosis.