Tyrosine hydroxylase (TH) is the initial and rate-limiting enzyme in the synthesis of the neurotransmitter dopamine. TH is inhibited and nitrated at tyrosine residues in vitro by the reactive nitrogen species peroxynitrite and nitrogen dioxide (NO2) and in vivo by drugs that damage dopamine neurons. Tetrahydrobiopterin, which is the essential cofactor for TH and is concentrated in dopamine neur...

Bovine liver glutamate dehydrogenase is desensitized to its allosteric inhibitor guanosine triphosphate upon reaction with tetranitromethane. The presence of GTP affords at most only a small protection against loss of the inhibitory effect of GTP. By amino acid analysis, the nitration of tyrosine appears to be the major change in the protein upon reaction with tetranitromethane and the modifica...

An oxidative and acid-free method for the nitration of N-aryl sulfonamides has been developed using a combination of sodium nitrite as cheap and easy to handle NO2-source and the hypervalent iodine reagent PIFA as stoichiometric oxidant. Under very mild reaction conditions, the desired mononitrated aryl sulfonamides were isolated in up to 87% yield. This is the first example of an iodane-mediat...

Protein tyrosine nitration increases in vivo as a result of oxidative stress and is elevated in numerous inflammatory-associated diseases. Mammalian fructose-1,6-bisphosphate aldolases are tyrosine nitrated in lung epithelial cells and liver, as well as in retina under different inflammatory conditions. Using two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization ti...

The film and the Danckwerts penetration models were used to model the heterogeneous liquid–liquid reaction of benzene nitration. Analytical solutions were developed for both models considering a pseudo-first order reaction. Models were confronted with experimental results showing good predictions in the intermediate reaction regime (0.3<Ha< 2). Profiles of both models were evaluated confirming ...

One of the successful strategies for the design of promising new energetic materials is the incorporation of both fuel and oxidizer moieties into the same molecule. Therefore, during recent years, synthesis of various nitro-azole derivatives, as compounds with a more balanced oxygen content, has become very popular. In the framework of this effort, we studied nitration of N(3),N(6)-bis(1H-tetra...

An initial rate approach was used to study the reaction of peroxynitrite with human serum albumin (HSA) through stopped-flow spectrophotometry. At pH 7.4 and 37 degreesC, the second order rate constant for peroxynitrite reaction with HSA was 9.7 +/- 1.1 x 10(3) M-1 s-1. The rate constants for sulfhydryl-blocked HSA and for the single sulfhydryl were 5.9 +/- 0.3 and 3.8 +/- 0.8 x 10(3) M-1 s-1, ...

Density-functional theory (DFT) calculations at the LC-wHPBE/6-311++G(d,p) level found that textbook three-step nitration mechanism of benzene in mixed acids was seriously wrong. Step 1 generating nitronium ion (NO2+) is not spontaneous, NO2+ generated by Lewis collision, and needs to overcome a barrier Ea = 18 or 22 kcal/mol acid nitric acid. Obtaining collision quantum chemical highlight stud...

Myeloperoxidase is a heme enzyme of neutrophils that uses hydrogen peroxide to oxidize chloride to hypochlorous acid. Recently, it has been shown to catalyze nitration of tyrosine. In this study we have investigated the mechanism by which it oxidizes nitrite and promotes nitration of tyrosyl residues. Nitrite was found to be a poor substrate for myeloperoxidase but an excellent inhibitor of its...

Protein tyrosine nitration is an important reactive oxygen species/reactive nitrogen species (ROS/RNS)-related modification that is derived from the main in vivo peroxynitrite pathway and the secondary myeloperoxidase reaction pathway (Scaloni, 2006, Khan et al., 1998, Zhan & Desiderio, 2009a, 2009b, and 2009c, Dalle-Donne et al., 2005, Zhan, Wang, & Desiderio, 2013). Tyrosine nitration adds an...