Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.23.17 (PCE)
 1,301 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tetrachloroethene (PCE) respiration was studied in the tetrachloroethene-utilizing anaerobe, Dehalospirillum multivorans, with respect to localization of the catabolic enzymes, the electron carriers potentially involved in electron transport, and the response to ionophores and specific inhibitors. Hydrogenase and formate dehydrogenase were recovered in the periplasmic cell fraction and were membrane-associated. Electron-accepting tetrachloroethene dehalogenase was found in the cytoplasmic fraction. In the PCE dehalogenase assay, only artificial electron donors with a standard redox potential of D. multivorans (Eo' = -445 mV) could serve as electron donor for PCE reduction. However, the reaction rate with ferredoxin was only 1% of that with methyl viologen, whereas the pyruvate-ferredoxin oxidoreductase exhibited almost the same reaction rates with methyl viologen and ferredoxin as electron acceptors for pyruvate oxidation. Reduced menadione (2-methyl-1, 4-naphthoquinone) did not serve as electron donor in the PCE dehalogenase reaction. 2-Heptyl-4-hydroxyquinoline-N-oxide (HOQNO) had no significant effect on PCE dechlorination in cell suspensions and in crude extracts. Whole cells catalyzed the reductive dechlorination of PCE with H2 or formate as electron donors. The dechlorination in cell suspensions rather than in cell extracts was inhibited by the ionophores carbonylcyanide-p-(trifluoromethoxy)phenylhydrazone (FCCP) and tetrachlorosalicylanilide (TCS), indicating that a membrane potential and/or a pH gradient may be required for the reaction in vivo.
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PMID:Studies on tetrachloroethene respiration in Dehalospirillum multivorans. 908 14

DNA and RNA transcripts, particularly of genes of functional importance in the reductively dechlorinating microbe Dehalococcoides, are increasingly being studied as potential molecular bioindicators of reductive dechlorination. Ideally, mRNA bioindicators would be informative both qualitatively (with respect to dechlorination end point and substrate range) and quantitatively (with respectto activity rates). Here, we examined pseudo-steady-state mRNA levels in Dehalococcoides-containing microcosms continuously fed PCE at various loading rates. We characterized gene transcript abundance of potential Dehalococcoides bioindicators of reductive dechlorination, including 16S rRNA, and genes encoding an annotated formate dehydrogenase (Fdh), the hydrogenase (H2ase) Hup, and the reductive dehalogenases (RDases) TceA, DET1559, PceA, and DET1545. Increases in steady PCE loading rate led to corresponding increases in PCE respiration rate (1.5 +/- 0.1, 2.5 +/- 0.3, 4.8 +/- 0.1, and 9.2 +/- 0.5 micromol/L/hr). We also observed that pseudo-steady-state expression levels of most functional targets increase linearly over PCE respiration rates of 1.5-4.8 micromol/L/hr, with Fdh, Hup, and TceA transcripts increasing by approximately 2 x 10(10) copies per mL of culture for every micromol/L/hr increase in chloroethene respiration rate, and DET1559 and PceAtranscripts increasing by approximately9 x 10(9) copies per mL of culture, butthat increased respiration rates of 9.2 micromol/L/hr did not necessarily lead to corresponding increases in transcript levels.
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PMID:Correlation of respiratory gene expression levels and pseudo-steady-state PCE respiration rates in Dehalococcoides ethenogenes. 1828 40