Glutathione conjugation of dopamine o-quinone and aminochrome. GST M2-2 catalyzes conjugation of both aminochrome and its precursor dopamine o-quinone to 4-S-glutathionyl-5,6-dihydroxyindoline and 5-glutathionyl-dopamine, respectively. 5-Glutathionyl-dopamine undergoes degradation to 5-cysteinyl dopamine that have been found in both the cerebrospinal fluid and neuromelanin.
