Hypotaurine and Superoxide Dismutase

Abstract

Hypotaurine is able to prevent the inactivation of SOD by H₂O₂. The protectionis concentration-dependent: at 20 mM hypotaurine the inactivation of SOD is completely prevented. It is likely that hypotaurine exerts this effect by reacting with hydroxyl radicals, generated during the inactivation process, in competition with the sensitive group on the active site of the enzyme. According to this, spectral studies indicate that in presence of hypotaurine the integrity of the active site of SOD is preserved by the disruptive action of H₂O₂ An interesting outcome of the SOD/H2O2/hypotaurine interaction is that SOD catalyzes the peroxidation of hypotaurine to taurine. Indeed, the formation of taurine increases with the reaction time and with the enzyme concentration. Although the peroxidase activity of SOD is not specific and relatively slow compared to the dismutation of superoxide, it might represent another valuable mechanism of production of taurine.