Snitrosierte

Snitrosierte is a term used to describe molecules that have been modified by the attachment of a nitroso group, most commonly through S-nitrosation of a thiol to form an S-nitrosothiol (RS-NO). In biology and chemistry, snitrosierte compounds are referred to as S-nitrosated or S-nitrosylated species. The nitroso group can modulate the chemical reactivity and function of the recipient molecule, making snitrosierte compounds important in redox signaling and regulatory pathways.

Formation and chemistry: S-nitrosation typically occurs when a thiol (RSH) reacts with nitrosating agents such as nitrous acid (generated from nitrite under acidic conditions), nitrosyl chloride, or nitrosogroup donors. The reaction introduces the -NO group onto sulfur, yielding RS-NO and a proton or water as byproducts. S-nitrosation is often reversible and sensitive to the cellular redox state, pH, and the local environment around the thiol. While S-nitrosation is common for cysteine residues in proteins, other thiols and low-molecular-weight thiols can also form snitrosierte species.

Biological relevance: S-nitrosation modulates protein activity, protein–protein interactions, and signaling pathways, and can function as a reservoir and donor of nitric oxide (NO). Snitrosierte species are studied as regulators of vascular tone, neurotransmission, and immune responses. However, some nitrosation pathways can lead to toxic or mutagenic compounds, such as certain N-nitrosamines formed from amines under nitrosating conditions.

Detection and stability: RS-NO groups are relatively labile and can decompose to NO or form disulfides. Detection methods include UV–visible spectroscopy, chemiluminescence after selective reduction, and mass spectrometry. Experimental conditions must account for potential artifactual nitrosation during sample handling.

See also: nitrosation, S-nitrosylation, nitrosothiol, RS-NO.