Anti-Nitrotyrosine Antibodies for Immunohistochemistry

Nitrotyrosine is an important marker for the formation of peroxynitrite and possibly other reactive nitrogen species derived from nitric oxide in vivo (1 ). Pathological conditions can substantially increase the production of nitric oxide, yet this molecule itself does not generally yield nitration of tyrosine residues in proteins when added to biological samples (1 ,2 ). However nitric oxide reacts at near diffusion-limited rates with superoxide (O₂ ⁻ ) to form the strong oxidant peroxynitrite (ONOO⁻ ) (3 ). Nitration on the 3-position of tyrosine is a major product of peroxynitrite attack on proteins (4 ,5 ). Certainly, small amounts of nitrotyrosine can be produced in vivo by other mechanisms (6 ), but peroxynitrite is by far the most efficient mechanism for nitrating tyrosine under biologically relevant conditions with natural antioxidants and alternative targets present.