Reactivation of the Hydrogenase from Desulfouibrio gigus by Hydrogen INFLUENCE OF REDOX
نویسندگان
چکیده
The specific activity of the periplasmic hydrogenase from Desulfovibrio gigas is increased approximately 10-fold in the Hz utilization assay with benzyl viologen by several hours of incubation under an atmosphere of Hz. After a variable lag phase during which residual traces of O2 are removed, the reversible activation is exponential. The extent of activation is dependent on pH and the redox potential of the incubation medium. A tentative model based on the existence of a monoelectronic redox center is proposed as shown in the following equation: E + H+ + ee E inactive active hydrogenase hydrogenase
منابع مشابه
Rewiring hydrogenase-dependent redox circuits in cyanobacteria.
Hydrogenases catalyze the reversible reaction 2H(+) + 2e(-) ↔ H(2) with an equilibrium constant that is dependent on the reducing potential of electrons carried by their redox partner. To examine the possibility of increasing the photobiological production of hydrogen within cyanobacterial cultures, we expressed the [FeFe] hydrogenase, HydA, from Clostridium acetobutylicum in the non-nitrogen-f...
متن کاملEngineering Synechocystis PCC6803 for Hydrogen Production: Influence on the Tolerance to Oxidative and Sugar Stresses
In the prospect of engineering cyanobacteria for the biological photoproduction of hydrogen, we have studied the hydrogen production machine in the model unicellular strain Synechocystis PCC6803 through gene deletion, and overexpression (constitutive or controlled by the growth temperature). We demonstrate that the hydrogenase-encoding hoxEFUYH operon is dispensable to standard photoautotrophic...
متن کاملIsolation of a hydrogenase-cytochrome b complex from cytoplasmic membranes of Xanthobacter autotrophicus GZ 29
The aerobic nitrogen-fixing hydrogen bacterium Xanthobacter autotrophicus strain GZ29 [1] can grow autotrophically with hydrogen, oxygen, carbon dioxide, and molecular nitrogen as sole sources of electrons, energy, carbon, and nitrogen. Carbon dioxide is fixed via the Calvin cycle, and for activation of hydrogen only a membrane-bound hydrogenase activity was detected which does not reduce NAD [...
متن کاملInfluence of Escherichia coli hydrogenases on hydrogen fermentation from glycerol
Since the actual role of Escherichia coli hydrogenases on fermentation from glycerol has not been clear, we evaluated the effect of inactivation of each E. coli hydrogenase on cell growth, hydrogen production, organic acids production, and ethanol production. Inactivation of hydrogenase 2 and hydrogenase 3 reduced cell growth, hydrogen and succinate production as well as glycerol utilization wh...
متن کاملRegulation of uptake hydrogenase and effects of hydrogen utilization on gene expression in Rhodopseudomonas palustris.
Rhodopseudomonas palustris is a purple, facultatively phototrophic bacterium that uses hydrogen gas as an electron donor for carbon dioxide fixation during photoautotrophic growth or for ammonia synthesis during nitrogen fixation. It also uses hydrogen as an electron supplement to enable the complete assimilation of oxidized carbon compounds, such as malate, into cell material during photoheter...
متن کامل