Mercury Toxicity on Sodium Pump and Organoseleniums Intervention: A Paradox

Abstract

Mercury is an environmental poison, and the damage to living system is generally severe. The severity of mercury poisoning is consequent from the fact that it targets the thiol-containing enzymes, irreversibly oxidizing their critical thiol groups, consequently leading to an inactivation of the enzyme. The Na+/K+-ATPase is a sulfhydryl protein that is sensitive to Hg2+assault. On the other hand, organoseleniums are a class of pharmacologically promising compounds with potent antioxidant effects. While Hg2+oxidizes sulfhydryl groups of Na+/K+-ATPase underin vitroandin vivoconditions, the organoselenium compounds inhibit Na+/K+-ATPasein vitrobut enhance its activities underin vivoconditions with concomitant increase in the level of endogenous thiols. Paradoxically, it appears that these two thiol oxidants can be used to counteract one another underin vivoconditions, and this hypothesis serves as the basis for this paper.