PMID:12420163
| Citation |
Laurinavichene, TV, Zorin, NA and Tsygankov, AA (2002) Effect of redox potential on activity of hydrogenase 1 and hydrogenase 2 in Escherichia coli. Arch. Microbiol. 178:437-42 |
|---|---|
| Abstract |
This report elucidates the distinctions of redox properties between two uptake hydrogenases in Escherichia coli. Hydrogen uptake in the presence of mediators with different redox potential was studied in cell-free extracts of E. coli mutants HDK103 and HDK203 synthesizing hydrogenase 2 or hydrogenase 1, respectively. Both hydrogenases mediated H(2) uptake in the presence of high-potential acceptors (ferricyanide and phenazine methosulfate). H(2) uptake in the presence of low-potential acceptors (methyl and benzyl viologen) was mediated mainly by hydrogenase 2. To explore the dependence of hydrogen consumption on redox potential of media in cell-free extracts, a chamber with hydrogen and redox ( E(h)) electrodes was used. The mutants HDK103 and HDK203 exhibited significant distinctions in their redox behavior. During the redox titration, maximal hydrogenase 2 activity was observed at the E(h) below -80 mV. Hydrogenase 1 had maximum activity in the E(h) range from +30 mV to +110 mV. Unlike hydrogenase 2, the activated hydrogenase 1 retained activity after a fast shift of redox potential up to +500 mV by ferricyanide titration and was more tolerant to O(2). Thus, two hydrogenases in E. coli are complementary in their redox properties, hydrogenase 1 functioning at higher redox potentials and/or at higher O(2) concentrations than hydrogenase 2. |
| Links |
PubMed Online version:10.1007/s00203-002-0471-x |
| Keywords |
Electron Transport; Enzyme Activation; Escherichia coli/drug effects; Escherichia coli/enzymology; Escherichia coli/genetics; Escherichia coli/metabolism; Hydrogen/pharmacology; Hydrogenase/isolation & purification; Hydrogenase/metabolism; Kinetics; Oxidation-Reduction; Oxidoreductases/genetics; Oxidoreductases/metabolism; Oxygen/pharmacology |
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