Antioxidant chemistry: Hypotaurine-taurine oxidation by chlorite

Extensive experimental data have been collected on the oxidation of hypotau rine, H2NCH2CH2SO2H, by chlorite and chlorine dioxide. Hypotaurine is stabl e and reacts slowly with chlorite to give taurine, hypotaurine sulfonic aci d, and monochloro- and dichlorotaurine. However, it reacts rapidly with chl orine dioxide with a second-order rate constant of 801 M-1 s(-1) to give ta urine. Oxidation occurs simultaneously at the sulfur center (to give the su lfonic acid) and at the nitrogen center (to give the chloramines). The stoi chiometry of the reaction was experimentally determined to be ClO2- + H2NCH 2CH2SO2H + H+ --> ClHNCH2CH2SO3H + H2O. The formation of dichlorotaurine is favored only in high acid environments.