nitrosativen

Nitrosative refers to processes and species related to nitroso groups or nitrogen monoxide derivatives. In chemistry, nitrosative processes include nitrosation, where a nitroso group (-NO) is introduced into substrates such as amines to form N-nitrosamines, and nitrosylation, the addition of nitric oxide (NO) to metal centers or thiol groups to form metal-NO complexes or S-nitrosothiols (RS-NO). Nitrosation can lead to stable N-nitroso compounds; nitrosylation is a key mechanism in signaling and enzyme regulation.

In biology, reactive nitrogen species (RNS) such as nitric oxide (NO), nitrogen dioxide (NO2), dinitrogen trioxide (N2O3), and peroxynitrite (ONOO−) drive nitrosative chemistry. Physiological nitrosation and nitrosylation regulate protein function and signaling via S-nitrosylation of cysteine residues and metal nitrosylation of heme groups. At controlled levels, nitrosative signaling participates in vasodilation, neurotransmission, and immune defense.

Nitrosative stress describes conditions where excessive RNS formation overwhelms antioxidant defenses, causing modifications and damage, including S-nitrosylation of critical proteins, tyrosine nitration (3-nitrotyrosine), lipid peroxidation, and DNA damage. This state has been implicated in inflammation, neurodegeneration, cardiovascular disease, and aging.

Measurement and study typically involve detecting nitrosothiols, nitrite/nitrate as RNS proxies, and protein nitration products. Distinguishing nitrosative from nitrative chemistry is important: nitro groups (-NO2) arise from nitration, whereas nitroso (-NO) and nitrosyl (-NO) chemistries define nitrosative processes. The term is used in chemistry and biomedicine to describe these nitrogen-centered phenomena.