S-Nitrosothiol

S-Nitrosothiols, also known as thionitrites, are organic compounds or functional groups containing a nitroso group attached to the sulfur atom of a thiol. S-Nitrosothiols have the general formula RSNO, where R denotes an organic group.

S-Nitrosothiols have received much attention in biochemistry because they serve as donors of the nitrosonium ion NO, and nitric oxide and some organic nitroso derivatives serve as signaling molecules in living systems, especially related to vasodilation. Red blood cells, for instance, release S-nitrosothiols into the bloodstream under low-oxygen conditions, causing the blood vessels to dilate.