Reactive nitrogen and oxygen species
Puzanowska-Tarasiewicz, H.; Kuźmicka, L.ła.; Tarasiewicz, M.ła.
Polski Merkuriusz Lekarski Organ Polskiego Towarzystwa Lekarskiego 27(160): 338-340
2009
ISSN/ISBN: 1426-9686 PMID: 19928666 Document Number: 629605
Reactive nitrogen species (RNS) and reactive oxygen species (ROS) are mainly free radicals which including non-paired electrons. They are constantly formed as side products of biological reactions. They are also generated directly and indirectly by the cells which were exposed to environmental stress, i.e., UV radiation, ionizing radiation, xenobioticts, light-absorbing compounds, e.g., porphyrines. These factors, which are a source of free radicals, initiate a significant signaling cascade inducing many changes in cells, such as cancerogenic transformation or cell death. Cells protect themselves against oxidative stress by means of antioxidative enzymes and compounds which in their structure have redox sensitive spots.