RESUMEN

An NAD(P)H-dependent oxidoreductase has been purified approximately 40-fold from the soluble protein fraction of the dissimilatory iron-reducing, anaerobic, thermophilic bacterium Carboxydothermus ferrireducens. The enzyme, a flavoprotein, has broad-substrate specificity-reducing Fe(3+), Cr(6+), and AQDS with rates of 0.31, 0.33, and 3.3 U mg(-1) protein and calculated NADH oxidation turnover numbers of 0.25, 0.25, and 2.5 s(-1), respectively. Numerous quinones are reduced via a two-electron transfer from NAD(P)H to quinone, thus participating in managing oxidative stress by avoiding the formation of semiquinone radicals.

Asunto(s)

Bacterias/enzimología , Oxidorreductasas/genética , Animales , Flavoproteínas/química , Cobayas , Concentración de Iones de Hidrógeno , Hierro/química , Cinética , NAD/química , NADP/metabolismo , Estrés Oxidativo , Oxidorreductasas/química , Oxígeno/química , Quinonas/química , Solubilidad , Especificidad por Sustrato