FORMATION OF THE NO DONORS GLYCERYL MONONITRATE AND GLYCERYL MONONITRITE FROM THE REACTION OF PEROXYNITRITE WITH GLYCEROL

Peroxynitrite (ONOO-), formed from the rapid reaction of superoxide (O -2(-.)) with NO, is known to generate stable compounds capable of dona ting NO on reaction with thiols and molecules containing hydroxy group . Using glycerol a a model compound for the reactions of ONOO- with bi omolecules containing hydroxy groups, we separated the products and id entified them by HPLC/MS. It was shown that both glyceryl mononitrate and glyceryl mononitrite were formed and released NO on incubation wit h copper and L-cysteine. The compounds were stable over a period of 4 h when shielded from light and kept on ice. Slow spontaneous decomposi tion occurred in the buffer used for the bioassay, but this was not su fficient to explain the vasorelaxing properties of these NO donors. It is concluded that the stable organic nitrate and nitrite have the cap acity to be metabolized by vascular tissues, resulting in vasorelaxati on.