3-Nitrotyrosine (3-NTyr) is formed in vivo by the reaction of tyrosine with nitrating oxidants, superoxide and nitric acid ([http://www.ncbi.nlm.nih.gov/pubmed/1416975|Beckman et al., 1992]). Formation of reactive nitrogen species is presumed to play a major role in neuron death and the presence of free 3-NTyr is considered a marker for this biochemical event. It has been shown that 3-NTyr exhibits neurotoxicity when injected into rat dopaminergic cells. This neurotoxicity has been linked to the metabolism of 3-NTyr via the concerted action of the aromatic amino acid decarboxylase and monoamine oxidase. 3-Nitrotyramine is structurally similar to 3-NTyr, exhibits the same neurotoxic effects and is formed via decarboxylation of 3-NTyr in rat dopaminergic neuronal cells ([http://www.ncbi.nlm.nih.gov/pubmed/16763020|Blanchard-Fillion et al., 2006]). This decarboxylation has not been observed in microbes. 3-Nitrotyramine can be used as a nitrogen source by cultures of Escherichia coli utilizing a periplasmic amine oxidase (TynA) and cytosolic NAD-linked dehydrogenase (FeaB). The biodegradation pathway involves an initial oxidation to 4-hydroxy-3-nitrophenylacetaldehyde which is further oxidized to 4-hydroxy-3-nitrophenylacetate (Rankin et al., 2008). These E. coli cultures did not grow on 3-NTyr. The metabolism of 3-NTyr in Variovorax paradoxus JS171 and Burkholderia sp. strain JS165 is carried out by deamination and subsequent decarboxylation to the above mentioned 4-hydroxy-3-nitrophenylacetate. Monooxygenase-catalyzed denitration of 4-hydroxy-3-nitrophenylacetate yields homoprotocatechuate, for which bacterial metabolism is well established ([http://www.ncbi.nlm.nih.gov/pubmed/16461647|Nishino and Spain, 2006]).