Chloramines taurine chloramine

HOC1 released by activated leukocytes has been implicated in the tissue damage that characterizes chronic inflammatory diseases. The release of HOC1 can be measured by the production of taurine-chloramine. A group of substituted indole derivatives including indole, 2-methylindole,... 

Chloramines are considered as main products secondary to hypochlorite formation. Taurine is one of the most abundant sources of free amino groups in polymorphonuclear neutrophilic leukocytes, representing approximately 50% of all low-molecular-weight amines released by PMNs (G24, Z5), and taurine chloramine is formed immediately along with MPO-mediated HOC1 synthesis ... 

Formation of taurine chloramines and of other small-molecular-weight amines accounts for 90% of all chloramine output in stimulated PMNs (G24). Chloramine synthesis efficiency approaches 100% of the stoichiometic amount of HOC1 employed (W5). Though HOC1 reacts spontaneously, with taurine as a chlorine donor, taurine chloramine production in the presence of MPO is one order of magnitude faster than the spontaneous one (k = 4.4 x 105 versus k = 2.8 x 106 M-1s-1). This indicates that the MPO-mediated taurine chlorination reaction may involve an enzyme intermediate species rather then free HOC1. 

Choramines differ with respect to their oxidative and chlorinating properties. Taurine chloramine is quite stable, and due to its relatively long lifetime in biological milieu, can diffuse to places distant from its production site (T4, T5). On the... 

When the taurine chloramine uptake rate exceeds the rate of NADPH-dependent regeneration of GSH, there is a net loss of cellular GSH level, causing protein-thiol oxidation, ATP loss, and disruption of cellular metabolism. Heme moieties are the other target of chloramine attack on cellular constituents. Oxidation of hemoglobin to methemoglobin (and other hemoproteins to their oxidized derivatives) occurs at 10-fold excess of chloramine taurine molar concentration compared... 

The data presented above support the Levine and Oppenheim hypothesis (L25) that polymorpohonuclear leukocytes play some specific role in the induction of immunoresponse the MPO-dependent oxidation and chlorination of proteins seems to interface with the neutrophil function with functions of the lymphoidline cells (M6). Moreover, the HOC1 and chloramine taurine, which is its stable... 

Taurine chloramine inhibited the synthesis of nitric oxide and the release of tumour necrosis factor in activated RAW 264.7 cells (Park et al. 1993). Inhibition of NO production was dependent on taurine chloramine concentration and was accounted for by reduced expression of inducible nitric oxide synthase mRNA, regardless of activator combinations (Park et al. 1997). 

Kim, J.W and Kim, C. (2005). Inhibition of LPS-induced NO production by taurine chloramine in macrophages is mediated though Ras-ERK-NF-kappaB. Biochem. Pharmacol. 70, 1352-1360. 

Liu, Y, Tonna-DeMasi, M., Park, E., Schuller-Levis, G., and Quinn, M.R. (1998). Taurine chloramine inhibits production of nitric oxide and prostaglandin E2 in activated C6 glioma cells by suppressing inducible nitric oxide synthase and cyclooxygenase-2 expression. Brain Res. Mol. Brain Res. 59, 189-195. 

In addition to mcd, V-BrPO catalyzes the chlorination of phenol red to tetrachlorophenol blue [64], Chlorination of amines (e.g., taurine, ammonia, valine, serine, leucine) is also catalyzed by V-BrPO forming the stable chloramine derivative, even in the presence of dihydrogen peroxide. Unlike bromamines, the chloramine is not reduced by dihydrogen peroxide, or is reduced only very slowly [53],... 

V-acetylmethionine in quantities equal to LZM. Inactivation of LZM also may be restricted upon addition of /V-acetylcystine or /V-acetyltryptophan. The /V-acetylo-tryptophan competes with LZM for the oxidizing agent. Amino compounds binding hypochlorite to relatively stable chloramines, such as leucine, lysine, and taurine, do not protect LZM from MPO-mediated reaction. Oxidation of tryptophan residues in lysozyme molecules treated with HOC1 occurs along with a decrease of lysozyme spectral properties at 280 nm. 

The latter may diffuse into the phagosomes as well as into the extracellular space. The H2O2 itself is toxic, but longer lived, more toxic oxidants are also formed. Reaction of H2O2 wifh myeloperoxidase (Chapter 16) produces hypochlorous acid, (HOCl Eqs. 16-12, Eig. 18-24) and chloramines such as NHjCl, RNHCl, and RNCI2. An important intracellular chloramine may be that of taurine. 

Sulfur-containing amino acids like cysteine, methionine and tripeptide glutathione are very powerful antioxidants that participate in different stages of free-radical chain reactions of biomolecule oxidation [18]. For example, cysteine participates in the synthesis of taurine, the substance that effectively blocks the peroxide oxidation of lipids by binding hypochlorite anion to form chloramine complex. In any organism, cysteine and glutathione reduces the oxidized form of vitamin C to its initial active form while methionine (being an... 

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