Inhibition of selenite-catalyzed superoxide generation and formation of elemental selenium (Se degrees) by copper, zinc, and aurintricarboxylic acid (ATA)

Selenite catalyzes the oxidation of glutathione (GSH) with the subsequent generation of superoxide (O-2 .(-)). Copper, zinc, and aurintricarboxylic acid (ATA) were tested for their ability to inhibit both the selenite-catalyzed generation of superoxide and the conversion of selenite to elemental selenium (Se degrees). As measured by lucigenin-dependent chemiluminescence (CL), copper, zinc, and ATA were shown to inhibit significantly (P < 0.05) selenite-catalyzed CL in a concentration dependent manner. The inhibition of the selenium-catalyzed generation of superoxide by copper(II) was greater than by either zinc or ATA. In addition, Copper, zinc, and ATA all inhibited the conversion of selenite to Se degrees. Inhibition of selenite-catalyzed CL by copper, zinc, and ATA is believed to occur as the result of inhibition of Se2- and/or GSSe(-), the catalytic selenopersulfide anion of GSH.