Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.12.7.2 (hydrogenase)
 3,522 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two classes of mutants defective in benzyl viologen-linked formate dehydrogenase (FDH-BV) activity were isolated from Escherichia coli K12. Class I consisted of four mutants which were specifically devoid of FDH-BV activity. Their mutation mapped between the ssb and melA genes at 92 min on the genome, at a site recently designated fdhF by Pecher et al. (1985). The direction of transcription of gene fdhF was found to be counterclockwise on the E. coli chromosome in one Mudl(Aprlac) fusion mutant. Expression of the lac operon in this mutant was induced by formate and repressed by nitrate, nitrite or trimethylamine N-oxide. It was found to be dependent on the positive control exerted by the fdhA, B and C genes, possibly involved in selenium incorporation, and by an hydB gene affecting the formate hydrogenlyase pathway. Class II, represented by one Mudl(Aprlac) mutant, exhibited no FDH-BV activity and a reduced level of hydrogenase activity. The relevant fdv mutation was shown to be located at 58 min and to affect the expression of fdhF.
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PMID:Regulation of the fdhF gene encoding the selenopolypeptide for benzyl viologen-linked formate dehydrogenase in Escherichia coli. 311 41

It is shown that -2H+/K(+)-exchange through the H(+)-K(+)-pump, formed by the F0F1-ATPase and the Trk H system, H(+)-K(+)-exchange via H(+)-K(+)-antiporter, formed by the F0 and the Trk G (core) system [1-2], and production of H2 in anaerobically grown E.coli are changed in the mutants with defects in components of formate hydrogen lyase complex, oxidizing formate to CO2 and H2. 2H+/K(+)-exchange and H2 production are destroyed, but H(+)-K(+)-exchange with a variable stoichiometry for N,N'-dicyclohexyl-carbodiimide-sensitive ion fluxes is displayed in the fdhF mutant E.coli FM911, where formate dehydrogenase(H) is absent. 2H+/K(+)-exchange does not occur, but H(+)-K(+)-exchange with variable stoichiometry for N,N'-dicyclohexylcarbodiimide-sensitive ion fluxes and H2 production are observed in the uncD mutant E.coli AN817 with defect in beta subunit of the F1. Deletion of the hyc-operon in mutant E.coli HD700, led to absence of hydrogenase 3, destroys H(+)-K(+)-exchange and H2 production. H2 evaluation is shown in the E.coli K12(lambda) protoplasts, treated with toluene, by adding of NADH into the medium, containing ATP and K+. It is inhibited by N,N'-dicyclohexylcarbodiimide. H2 production is increased by adding of dithiothreitol, when NADH is changed by formate. It is lost in the mutants with defects in the F0 (E.coli AN936) or in the Trk A protein (E.coli TK2242). Dehydrogenase(H) and hydrogenase 3 are assumed to link mutually with a H(+)-K(+)-pump operation, reducing equivalents, necessary for a dithiol-disulfide interconversion within a mechanism of pump, are transferred from formate by means of dehydrogenase(H) to hydrogenase 3 through the F0F1 and the Trk H system to produce H2. It is assumed that hydrogenase 3 can interact with a mechanism of H(+)-K(+)-antiporter, NADH could serve as a donor of reducing equivalents. A role of thiol-groups and dithiol-disulfide interconversion in a functions of both mechanism for H(+)-K(+)-exchange is confirmed.
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PMID:[Role of components of formate-hydrogen-lyase in forming molecular hydrogen and their connection with proton-potassium exchange in anaerobically grown Escherichia coli]. 872 54

Escherichia coli HD701, a hydrogenase-upregulated strain, has the potential for industrial-scale H2 production but is unable to metabolise sucrose, which is a major constituent of many waste materials that could be used as feedstocks for H2 production processes. A 70 kb plasmid (pUR400), which carries the genes necessary for sucrose transport into the cell and its metabolism, was conjugated into E. coli strains HD701 and FTD701 [a derivative of HD701 which has a deletion of the tatC gene of the twin arginine transport (Tat) protein system] from an E. coli K12 strain. Comparative studies on H2 evolution by FTD701 and HD701, with and without the pUR400 plasmid, were made using sucrose as substrate. The parental strains did not evolve H2, although HD701/pUR400 and FTD701/pUR400 evolved 1.27 +/- 0.09 and 1.38 +/- 0.05 ml H2 mg dry wt(-1) l culture(-1), respectively over 10 h. This work provides the choice for using a recombinant E. coli strain, which produces H2 from sucrose, as an alternative to coupling-in an upstream invertase, and hence this provides a simpler method for the bioproduction of H2 from sucrose.
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PMID:Production of H2 from sucrose by Escherichia coli strains carrying the pUR400 plasmid, which encodes invertase activity. 1567 32