Reactive nitrogen species

Reactive nitrogen species ( engl. reactive nitrogen species, RNS) is the name given to highly reactive nitrogen compounds. They play an important role in a number of physiological as well as pathophysiological processes. Analogous to the reactive oxygen species that cause oxidative stress, reactive nitrogen species cause nitrosative stress. Thus, the reactive nitrogen species for some cell- pathological phenomena are responsible that were once exclusively attributed to the reactive oxygen species. The reactive nitrogen species nitric oxide and peroxynitrite derived product can be expected.

Formation

Relatively stable free radical nitric oxide (NO · ) is generated in the cells by the catalytic action of the enzyme NO- synthases (NOS). In this case, L-arginine to react with molecular oxygen to form nitric oxide and L- citrulline. The nitrogen monoxide formed is diffused to the cell membrane.

To the cell membrane by the enzyme NADPH oxidase (NOX) which is also free radical superoxide anion ( O2 · - ), is formed. In a diffusion-limited reaction, the nitric oxide reacts with the superoxide anion to the non- free radical, but highly reactive peroxynitrite:

Peroxynitrite is far more aggressive than its two precursor molecules because of its high redox potential.

Thus, peroxynitrite reacts with carbon dioxide to always present the short-lived Nitrosoperoxycarbonat ion, which is divided into two highly reactive radicals that are responsible for DNA damage by peroxynitrite:

In addition to animal cells, plant cells produce nitric oxide and thus potentially reactive nitrogen species.

Effects

The reactive nitrogen species are important for a variety of physiological processes. The primary mechanism is the induction of apoptosis (programmed cell death). Peroxynitrite is able to reduce the intracellular levels of glutathione and thereby induce apoptosis.

It is assumed that triggered by reactive nitrogen species nitrosative stress is involved in a number of neurological, inflammatory, metabolic and cardiovascular diseases.

Proof

A marker of nitrosative stress is nitrotyrosine. It is formed in the reaction of reaction with tyrosine derivatives, the nitrogen species, and can be detected in vitro using suitable methods.

Reactive nitrogen species

Formation

Effects

Proof

Further Reading