Pyruvate, ferredoxin oxidoreductase

In Desulfovibrio, as in other strict anaerobes and some aerobic microorganisms, pyruvate is oxidatively decarboxylated by pyruvate oxidoreductase (FOR) according to the following reaction  

Further studies have shown that D. africanus ferredoxins I and II are involved as physiological electron carriers of POR. Also, using immunogold labeling, it was possible to show that POR is located in the cytoplasm. 

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Ferredoxins are electron-transfer proteins that can mediate between pyruvate ferredoxin oxidoreductase and hydrogenase. It appears that during the course of the evolution, different types of ferredoxin were recruited for this purpose. In Clostridia, ferredoxins of the 2[4Fe-4S] type are used (Uyeda and Rabinowitz 1971). In T. vaginalis (Chapman et al. 1986) and T. foetus (Marczak et al. 1983), [2Fe-2S] ferredoxins are used. Their axial EPR spectra at g = 1.94,2.02 (Fig. 9.2) resemble those of the ferredoxins that are involved in P450 monooxygenase systems. Similar ferredoxins, with various functions, have been isolated from... 

Uyeda K, Rabinowitz JC. 1971. Pyruvate-ferredoxin oxidoreductase III. Purification and properties of the enzyme. J Biol Chem 246 311-19. 

Mechanism of Action An ant iparasiticthat interferes with the body s reaction to pyruvate ferredoxin oxidoreductase, an enzyme essential for anaerobic energy metabolism. Therapeutic Effect Produces antiprotozoal activity, reducing or terminating diarrheal episodes. 

Both hydrogenase and pyruvate-ferredoxin oxidoreductase activities were inhibited in nitrite-treated cells, and the inhibition was greater with addition of both nitrite and ascorbate (Payne et al., 1990a). However, they noted that enzyme inhibition was not complete. Meyer (1981) also reported incomplete in-... 

Based on the incomplete inhibition of iron-sulfur proteins by nitrite, and the observation that low-spin Fe—NO EPR signals were observed by C. sporogenes cultures that recovered from nitrite treatment, Payne et al. (1990a) concluded that the antimicrobial effect of nitrite or NO cannot be explained by direct inhibition of preformed pyruvate—ferredoxin oxidoreductase or hydrogenase. 

Carpenter, C. E., Reddy, D. S. A., and Cornforth, D. P. (1987). Inactivation of clostridial ferredoxin and pyruvate-ferredoxin oxidoreductase by sodium nitrite. Appl. Environ. Microbiol. 53, 549-552. 

Pyruvate ferredoxin oxidoreductase subunit A, PFORA MLRSFaGKRIPGDGNTAATSV Hrdy and Muller (1995a)... 

Dan M, Wang AL, Wang CC (2000) Inhibition of pyruvate-ferredoxin oxidoreductase gene expression in Giardia lamblia by a virus-mediated hammerhead ribozyme. Mol... 

Fig. 5 Speculative metabolic schemes of the main pathways in carbohydrate metabolism in Trimyema compressum (after Goosen et al. 1990). End products are in boxes. Abbreviations AcCoA, acetyl-Co A, Hyd, hydrogenase, PEP, phosphoenolpyruvate carboxykinase, PFL, pyruvate formate lyase, PFO, pyruvate ferredoxin oxidoreductase, PYR, pyruvate, Xox, red> unknown electron carrier...

Ctrnacta V, Ault JG, Stejskal F, Keithly JS (2006) Localization of pyruvate NADP(+) oxido-reductase in sporozoites of Cryptosporidiumparvum. J Eukaryot Microbiol 53 225-231 Dederck PJ, Muller M (1987) Hydrogenosomal ATP AMP phosphotransferase of Trichomonas vaginalis. Comp Biochem Physiol 88 575-580 Docampo R, Moreno SN, Mason RP (1987) Free radical intermediates in the reaction of pyruvate ferredoxin oxidoreductase in Tritrichomonas foetus hydrogenosomes. J Biol Chem 262 12417-12420... 

Horner DS, Hirt RP, Embley TM (1999) A single eubacterial origin of eukaryotic pyruvate ferredoxin oxidoreductase genes implications for the evolution of anaerobic eukaryotes. Mol Biol Evol 16 1280-1291... 

Hrdf I, Muller M (1995a) Primary structure and eubacterial relationships of the pyruvate ferredoxin oxidoreductase of the amitochondriate eukaryote Trichomonas vaginalis. J Mol Evol 41 388-396... 

Docampo R, Moreno SN, Mason RP (1987) Free radical intermediates in the reaction of pyruvate ferredoxin oxidoreductase in Tritrichomonas foetus hydrogenosomes. J Biol Chem 262 12417-12420... 

Samarawickrema NA, Brown DM, Upcroft JA, Thammapalerd N, Upcroft P (1997) Involvement of superoxide dismutase and pyruvate ferredoxin oxidoreductase in mechanisms of metronidazole resistance in Entamoeba histolytica. J Antimicrob Chemother 40 833-840... 

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