Pugh S Y, DiGuiseppi J L, Fridovich I
J Bacteriol. 1984 Oct;160(1):137-42. doi: 10.1128/jb.160.1.137-142.1984.
Growth of Escherichia coli B in simple media enriched with Mn(II) resulted in the elevation of the manganese-containing superoxide dismutase, whereas growth in such medium enriched with iron caused increased content of the iron-containing superoxide dismutase. Enrichment of the medium with Co(II), Cu(II), Mo(VI), Zn(II), or Ni(II) had no effect. The inductions of superoxide dismutase by Mn(II) or by Fe(II) were dioxygen dependent, but these metals did not affect the CN- -resistant respiration of E. coli B and did not influence the increase in the CN- -resistant respiration caused by paraquat. Mn(II) and paraquat acted synergistically in elevating the superoxide dismutase content, and Mn(II) reduced the growth inhibition imposed by paraquat, E. coli grown in the complex 3% Trypticase soy broth (BBL Microbiology Systems)-0.5% yeast extract-0.2% glucose medium contained more superoxide dismutase than did cells grown in the simple media and were less responsive to enrichment of the medium with Mn(II) or Fe(II). Nevertheless, in the presence of paraquat, inductions of superoxide dismutase by these metals could be seen even in the Trypticase-yeast extract-glucose medium. On the basis of these observations we propose that the apo-superoxide dismutases may act as autogenous repressors and that Mn(II) and Fe(II) increase the cell content of the corresponding enzymes by speeding the conversion of the apo- to the holoenzymes.
在富含锰（II）的简单培养基中培养大肠杆菌B，会导致含锰超氧化物歧化酶含量升高；而在富含铁的此类培养基中生长，则会使含铁超氧化物歧化酶含量增加。培养基中添加钴（II）、铜（II）、钼（VI）、锌（II）或镍（II）则没有影响。锰（II）或铁（II）对超氧化物歧化酶的诱导作用依赖于氧气，但这些金属并不影响大肠杆菌B对氰化物抗性的呼吸作用，也不影响百草枯引起的对氰化物抗性呼吸作用的增加。锰（II）和百草枯在提高超氧化物歧化酶含量方面具有协同作用，并且锰（II）减轻了百草枯对生长的抑制作用。在复杂的3%胰蛋白胨大豆肉汤（BBL微生物系统）-0.5%酵母提取物-0.2%葡萄糖培养基中生长的大肠杆菌比在简单培养基中生长的细胞含有更多的超氧化物歧化酶，并且对培养基中添加锰（II）或铁（II）的反应较小。然而，在百草枯存在的情况下，即使在胰蛋白胨-酵母提取物-葡萄糖培养基中，这些金属对超氧化物歧化酶的诱导作用也能被观察到。基于这些观察结果，我们提出脱辅基超氧化物歧化酶可能作为自身阻遏物起作用，并且锰（II）和铁（II）通过加速脱辅基酶向全酶的转化来增加相应酶的细胞含量。
