REGULATION OF THE PERIPLASMIC [FE] HYDROGENASE BY FERROUS IRON IN DESULFOVIBRIO-VULGARIS (HILDENBOROUGH)

The periplasmic [Fe] hydrogenase from the sulfate-reducing bacterium Desulfovibrio vulgaris (Hildenborough) DSM 8303 was found to be regulated by ferrous iron availability. During growth with 5 ppm of iron, the enzyme derepressed and the specific activity increased approximately fourfold, whereas the presence of 100 ppm of ferrous iron repressed the enzyme. The repression-derepression phenomenon with ferrous iron was found to be operative when the cells were cultured under either hydrogen or nitrogen gas. This is the first reported case showing that the hydrogenase enzyme is regulated by iron, and the implications of this finding relative to the corrosion industry are discussed.