Nitrotyrosine is a post-translational modification that is formed by the nitration of tyrosine. Under conditions of oxidative stress, tyrosine is oxidized by reactive oxygen species (ROS) or, in the presence of hydrogen peroxide and nitrite, by myeloperoxidase (MPO) to yield a tyrosine radical that reacts with reactive nitrogen species (RNS), such as nitric oxide or peroxynitrite, to form nitrotyrosine. It exists in a free or protein-bound form and is commonly used as a marker of nitrosative or oxidative stress. Nitrotyrosine residues have been found in a variety of proteins, including LDL, surfactant protein A, angiotensin II, and human and bovine serum albumin. Free nitrotyrosine production induced by peroxynitrite is inhibited by the polyphenols epicatechin gallate, gallic acid, catechin, or epicatechin in cell-free assays, as well as in aortic rings isolated from normotensive and spontaneously hypertensive rats administered the antioxidant N-acetyl-cysteine (NAC; ). Nitrotyrosine levels are increased in the affected tissues of numerous pathological conditions, including atherosclerosis, cancer, ulcerative colitis, Alzheimer''s disease, and Parkinson''s disease. Autoantibodies that recognize nitrotyrosinated proteins are increased in the synovium of patients with rheumatoid arthritis and are positively correlated with joint and tendon inflammation. Cayman''s Nitrotyrosine Monoclonal Antibody can be used for ELISA and Western blot (WB) applications.
