1. 1. The reaction of methyl phenyldiazenecarboxylate ("azoester", C6H6H5N = NCOOCH3) with GSH produces methyl phenyldiazanecarboxylate ("hydrazoester", C6H5NHNHCOOCH3) and GSSG. The stoichiometry of the reaction follows the equation: 2 GSH + C6H5N = NCOOCH3 → C6H5NHNHCOOCH3 + GSSG 2. 2. The rate of the reaction depends upon the concentration of azoester and GSH. 3. 3. Evidence for an intermediate composed of GSSG and hydrazoester is presented. 4. 4. The mechanism of the overall reaction between azoester and GSH involves two intermediates. 5. 5. Other reactions of azoester of importance to the GSH oxidation procedure are described.