Unden G, Trageser M, Duchêne A
Institut für Mikrobiologie, J. W. Goethe-Universität, Frankfurt, FRG.
Mol Microbiol. 1990 Feb;4(2):315-9. doi: 10.1111/j.1365-2958.1990.tb00598.x.
The expression of fumarate reductase and other enzymes of anaerobic respiration in Escherichia coli was studied as a function of the redox potential (Eh) in the medium. Redox potentials up to +300 mV allowed full expression of fumarate reductase (frd) genes. Higher values resulted in decreased expression. The relationship between Eh and expression of frd could be approximated by the Nernst equation, assuming a redox couple with a midpoint potential Eo' = +400 mV to 440 mV. At Eh values greater than +510 mV (generated anaerobically by hexacyanoferrate(III] the degree of repression was the same as that obtained by O2. Hexacyanoferrate(III) also caused decreased activities of dimethylsulphoxide (DMSO), nitrite and nitrate reductases. Since expression of these enzymes depends on FNR, the gene activator of anaerobic respiratory genes, it is suggested that the function of FNR is controlled by a redox couple of Eo' = +400 mV to 440 mV.
研究了大肠杆菌中延胡索酸还原酶和其他无氧呼吸酶的表达与培养基中氧化还原电位（Eh）的关系。高达+300 mV的氧化还原电位可使延胡索酸还原酶（frd）基因充分表达。更高的值会导致表达降低。假设存在一个中点电位Eo' = +400 mV至440 mV的氧化还原对，则Eh与frd表达之间的关系可用能斯特方程近似。在Eh值大于+510 mV时（由铁氰化铁（III）厌氧产生），阻遏程度与O2产生的相同。铁氰化铁（III）还导致二甲基亚砜（DMSO）、亚硝酸盐和硝酸盐还原酶的活性降低。由于这些酶的表达取决于无氧呼吸基因的基因激活剂FNR，因此表明FNR的功能受Eo' = +400 mV至440 mV的氧化还原对控制。
