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C Reductase (c + reductase)
Selected AbstractsFocused proteomics: Monoclonal antibody-based isolation of the oxidative phosphorylation machinery and detection of phosphoproteins using a fluorescent phosphoprotein gel stainELECTROPHORESIS, Issue 15 2004James Murray Abstract We have raised monoclonal antibodies capable of immunocapturing all five complexes involved in oxidative phosphorylation for evaluating their post-translational modifications. Complex I (NADH dehydrogenase), complex II (succinate dehydrogenase), complex III (cytochrome c reductase), complex IV (cytochrome c oxidase), and complex V (F1F0 ATP synthase) from bovine heart mitochondria were obtained in good yield from small amounts of tissue in more than 90% purity in one step. The composition and purity of the complexes was evaluated by Western blotting using monoclonal antibodies against individual subunits of the five complexes. In this first study, the phosphorylation state of the proteins without inducing phosphorylation or dephosphorylation was identified by using the novel Pro-Q Diamond phosphoprotein gel stain. The major phosphorylated components were the same as described before in sucrose gradient enriched complexes. In addition a few additional potential phosphoproteins were observed. Since the described monoclonal antibodies show cross reactivity to human proteins, this procedure will be a fast and efficient way of studying post-translational modifications in control and patient samples using only small amounts of tissue. [source] Evidence for redox cycling of lawsone (2-hydroxy-1,4-naphthoquinone) in the presence of the hypoxanthine/xanthine oxidase systemJOURNAL OF APPLIED TOXICOLOGY, Issue 4 2003A. M. Osman Abstract This study reports that lawsone (2-hydroxy-1,4-naphthoquinone) undergoes redox cycling in the presence of the hypoxanthine/xanthine oxidase system. The rate of cytochrome c reduction obtained in the presence of 80 µM lawsone was almost three times the rate of cytochrome c reduction measured in its absence. This increase in the rate of cytochrome c reduction was partially inhibited by superoxide dismutase, suggesting the involvement of O2,, in this process. It is remarkable to note that, even though lawsone is considered to be a non-redox-cycling quinone in vitro, this quinone was shown to be more toxic in vivo in rats than menadione, causing haemolytic anemia of an oxidative nature and renal damage. The view that this quinone is a non-redox-cycling quinone was based on the inability of one-electron-transferring ,avoenzymes such as NADPH-cytochrome c reductase to reduce this naphthoquinone. Our ,nding that lawsone, like menadione, undergoes redox cycling in the presence of the hypoxanthine/xanthine oxidase system could explain the observed oxidative damage of tissues in,icted by this quinone in rats in vivo. Such an observation therefore reconciles the in vivo toxicity results of this naphthoquinone with those of in vitro experiments. Copyright © 2003 John Wiley & Sons, Ltd. [source] Structural and functional organization of Complex I in the mitochondrial respiratory chainBIOFACTORS, Issue 1-4 2003Cristina Bianchi Abstract Metabolic flux control analysis of NADH oxidation in bovine heart submitochondrial particles revealed high flux control coefficients for both Complex I and Complex III, suggesting that the two enzymes are functionally associated as a single enzyme, with channelling of the common substrate, Coenzyme Q. This is in contrast with the more accepted view of a mobile diffusable Coenzyme Q pool between these enzymes. Dilution with phospholipids of a mitochondrial fraction enriched in Complexes I and III, with consequent increased theoretical distance between complexes, determines adherence to pool behavior for Coenzyme Q, but only at dilution higher than 1:5 (protein:phospholipids), whereas, at lower phospholipid content, the turnover of NADH cytochrome c reductase is higher than expected by the pool equation. [source] MODULATORY EFFECT OF NARINGENIN ON N -METHYL- N, -NITRO- N -NITROSOGUANIDINE- AND SATURATED SODIUM CHLORIDE-INDUCED GASTRIC CARCINOGENESIS IN MALE WISTAR RATSCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 10 2008Ekambaram Ganapathy SUMMARY 1Naringenin is a flavanone that is believed to have many biological actions, including as an anti-oxidant, free radical scavenger and an antiproliferative agent. The global incidence of gastric carcinoma is increasing rapidly, more than for any other cancer. Therefore, in the present study, we tested the effects of naringenin on gastric carcinogenesis induced by N -methyl- N,-nitro- N -nitrosoguanidine (MNNG) and saturated sodium chloride (S-NaCl) in rats. 2Male Wistar rats were divided into five groups and treated over a period of 20 weeks as follows: (i) a control group given corn oil (1 mL/rat, p.o.) daily 20 weeks; (ii) 200 mg/kg, p.o., MNNG on Days 0 and 14 with S-NaCl (1 mL/rat) administered twice a week for the first 3 weeks; (iii) 200 mg/kg, p.o., MNNG on Days 0 and 14, with naringenin (200 mg/kg, p.o., daily) treatment for the entire 20 weeks; (iv) 200 mg/kg, p.o., MNNG on Days 0 and 14, with naringenin treatment (200 mg/kg, p.o., daily) initiated from 6 to 20 weeks; (v) 200 mg/kg, p.o., naringenin alone daily for 20 weeks. 3In Group II rats in which gastric cancer was inducted with MNNG and S-NaCl, there was a significant increase in hydrogen peroxide and lipid peroxidation levels, with decreases in reduced glutathione, oxidized glutathione, glutathione peroxidase, glutathione reductase and glucose 6-phosphate dehydrogenase. In addition, in Group II rats with gastric cancer, there were significant increases in the activity of cytochrome P450, cytochrome b5 and NADPH cytochrome c reductase, with concomitant decreases in the activity of the phase II enzymes glutathione S-transferase and UDP-glucuronosyl transferase. Naringenin treatment (Groups III and IV) restored enzyme activity to near control levels. 4These results indicate that naringenin has a chemopreventive action against MNNG-induced gastric carcinoma in experimental rats. [source] | ||||||||||