Nitrotyrosine (Stool, Plasma, Serum) ELISA

Nitrotyrosine is the nitrated form of the amino acid tyrosine. The accumulation of
protein bound nitrotyrosine is associated with cardiovascular diseases that are based
on inflammatory processes (e.g., atherosclerosis, myocardial infarction, diabetic vasculopathy,
hypertension, or coronary heart diseases). A growing number of studies
have also associated the accumulation of nitrotyrosine with neurological diseases
(Alzheimer´s disease, Parkinson´s disease, multiple sclerosis, stroke). With treatment
of some of the associated diseases the levels of nitrated tyrosines have been shown
to decrease, so nitrotyrosine has been stated to be a marker of nitrosative stress.
During inflammatory processes, large amounts of nitric oxide (•NO) are locally released
from L-arginine. This reaction is catalyzed by the enzyme NO-synthase (NOS).
Other causes for the increased •NO production are exposure to chemicals or heavy
metals, drugs, nicotine, or physical and psychological stress, as well as extraordinary
physical strain with increased oxygen consumption.
In high concentrations, •NO that is not trapped by mitochondrial superoxide dismutase
(MnSOD) reacts with superoxide (•OO–
) to form peroxynitrite (ONOO–
). Peroxynitrite
is implicated as a key oxidant species in several pathologies and is known to be
cytotoxic (nitrosative stress).
Peroxinitrite is highly reactive and shows a high affinity to aromatic amino acids, e.g.,
to the phenolic ring of tyrosine. The nitration of tyrosine in general is a natural process
within the post-translational protein modification.
Nitrotyrosine is a stable product and might be seen as a correlate of peroxynitrite
production, and its accumulation in cells and tissues is a marker of oxidative stress
and nitrosative stress, respectively