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 H2 uptake in the presence of high-potential acceptors (ferricyanide and phenazine methosulfate). H2 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 (Eh) 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 Eh below -80 mV. Hydrogenase 1 had maximum activity in the Eh 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 O2. Thus, two hydrogenases in E. coli are complementary in their redox properties, hydrogenase 1 functioning at higher redox potentials and/or at higher O2 concentrations than hydrogenase 2.
CITATION STYLE
Laurinavichene, T. V., Zorin, N. A., & Tsygankov, A. A. (2002). Effect of redox potential on activity of hydrogenase 1 and hydrogenase 2 in Escherichia coli. Archives of Microbiology, 178(6), 437–442. https://doi.org/10.1007/s00203-002-0471-x
Mendeley helps you to discover research relevant for your work.