Leukocytes NADPH

Historically, leukocyte NADPH oxidase was the first discovered enzyme of this type the existence of this enzyme in neutrophils was reported in 1962-1966 [59-61]. (As the evidence of superoxide production in biological systems has been obtained several years later, at that time the nature of oxygen species produced by leukocytes was of course unknown.) And only about 10 years later, Babior et al. [62] have shown that the activation of human neutrophils resulted in the production of superoxide. The structure of leukocyte NADPH has been widely discussed and well-established [57]. Superoxide production catalyzed by NADPH oxidase is described by Reaction (5) ... 

GillitzerR, GoebelerM Chemokines in cutaneous wound healing. JLeukoc Biol 2001 69 513-521. Jones SA, Wolf M, Qin S, Mackay CR, Baggiolini M Different functions for the interleukin 8 receptors (IL-8R) of human neutrophil leukocytes NADPH oxidase and phospholipase D are activated through IL-8R1 but not IL-8R2. Proc Natl Acad Sci USA 1996 93 6682-6686. 

Leukocytes are activated on exposure to bacteria and other stimuh NADPH oxidase plays a key role in the process of activation (the respiratory burst). Mutations in this enzyme and associated proteins cause chronic granulomatous disease. 

Thus, the mechanism of MT antioxidant activity might be connected with the possible antioxidant effect of zinc. Zinc is a nontransition metal and therefore, its participation in redox processes is not really expected. The simplest mechanism of zinc antioxidant activity is the competition with transition metal ions capable of initiating free radical-mediated processes. For example, it has recently been shown [342] that zinc inhibited copper- and iron-initiated liposomal peroxidation but had no effect on peroxidative processes initiated by free radicals and peroxynitrite. These findings contradict the earlier results obtained by Coassin et al. [343] who found no inhibitory effects of zinc on microsomal lipid peroxidation in contrast to the inhibitory effects of manganese and cobalt. Yeomans et al. [344] showed that the zinc-histidine complex is able to inhibit copper-induced LDL oxidation, but the antioxidant effect of this complex obviously depended on histidine and not zinc because zinc sulfate was ineffective. We proposed another mode of possible antioxidant effect of zinc [345], It has been found that Zn and Mg aspartates inhibited oxygen radical production by xanthine oxidase, NADPH oxidase, and human blood leukocytes. The antioxidant effect of these salts supposedly was a consequence of the acceleration of spontaneous superoxide dismutation due to increasing medium acidity. 

Heyneman, R. A., Vercauteren, R. E. (1984). Activation of a NADPH oxidase from horse polymorphonuclear leukocytes in a cell-free system. J. Leuk. Biol. 36, 751-9. 

Ohtsuka, T., Okamura, N., Ishibashi, S. (1986). Involvement of protein kinase C in the phosphorylation of 46 kDa proteins which are phosphorylated in parallel with activation of NADPH oxidase in intact guinea-pig polymorphonuclear leukocytes. Biochim. Biophys. Acta 332-7. 

Agwu, D. E., McPhail, L. C., Sozzani, S., Bass, D. A., McCall, C. E. (1991). Phosphati-dic acid as a second messenger in human polymorphonuclear leukocytes Effects on activation of NADPH oxidase. J. Clin. Invest. 88,531-9. 

Cassatella, M. A., Bazzoni, F., Calzetti, F., Guasparri, I., Rossi, F., Trinchieri, G. (1991). Interferon-/transcriptionally modulates the expression of the genes for the high affinity IgG-Fc receptor and the 47-kDa cytosolic component of NADPH oxidase in human polymorphonuclear leukocytes. J. Biol. Chem. 266, 22079-82. 

Phagocytic leukocytes that are exposed to opsonized particles, chemoattractants, or selected cytokines undergo a rapid burst in oxygen consumption and activation of the enzyme responsible for the oxidative metabolic burst, NADPH oxidase (reviewed in ref. 1). Active NADPH oxidase catalyzes the reaction ... 

Witz G, Lawrie NJ, Amoruso MA, et al. 1987. Inhibition by reactive aldehydes of superoxide anion radical production from stimulated polymorphonuclear leukocytes and pulmonary alveolar macrophages Effects of cellular sulfhydryl groups and NADPH oxidase activity. Biochem Pharmacol 36 721-726. 

An alternative source of the superoxide radical anion is leukocytic xanthine oxidase, acting in polymorphonuclear leukocytes of individuals with impairment of the NADPH oxidase system. Superoxide is one of the major metabolites produced in stimulated neutrophiles. Various estimations of Oj production yielded values ranging from 850 to 1350 p.mol/h/1010 cells (Bl, K16). 

Kindzelskii, A. and Petty, H. R. (2004). Fluorescence spectroscopic detection of mitochondrial flavoprotein redox oscillations and transient reduction of the NADPH oxidase-associated flavoprotein in leukocytes European Biophysics Journal with Biophysics Letters 33 291-299. 

The inhibitory effects of berbamine and ISO natural products on the cytotoxic activity of polymorphonuclear leukocytes (PMN) was investigated. The research employed the effects of natural products on the PMN activation by the antitumor immunomodulator TAK (a linear P-1,3-D-glucan from Alcaligenes faecalis var. myxogenes) using a PMN cytotoxicity assay system. Berbamine was found to inhibit the activation of PMN activation by TAK, showing an IDJ0 33 pg/ml. From this, and related studies, it was postulated that berbamine may impair the NADPH oxidase system in the plasma membrane of PMN [199]. 

D-Amino acid oxidase occurs in peroxisomes containing other enzymes that produce H2O2 (e.g., L-a-hydroxy acid oxidase, citrate dehydrogenase, and L-amino acid oxidase) and catalase and peroxidase, which destroy H2O2. In leukocytes, killing of bacteria involves hydrolases of lysosomes and production of H2O2 by NADPH oxidase (Chapter 15). Conversion of D-amino acids to the corresponding a-keto acids removes the asymmetry at the a-carbon atom. The keto acids may be aminated to L-amino acids. By this conversion from D- to L-amino acids, the body utilizes D-amino acids derived from the diet ... 

H2O2-generating system which may be an NADPH (NADH) oxidase system similar to that of leukocytes (Chapter 15). Thyroperoxidase is a glycosylated heme enzyme that is bound to the apical plasma membrane of the thyrocyte. Thyroperoxidase exists in two molecular forms (M.W. 105,000 and 110,000) and its catalytic domain faces the colloid space. In thyroid autoimmune disorders, one of the major microsomal antigenic components is thyroperoxidase. 

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