Human glutathione transferase M2-2 prevents the formation of neurotoxic ami
nochrome and dopachrome by catalyzing the conjugation of dopamine and dopa
o-quinone with glutathione. NMR analysis of dopamine and dopa o-quinone-glu
tathione conjugates revealed that the addition of glutathione was at C-5 to
form 5-S-glutathionyl-dopamine and 5-S-glutathionyldopa, respectively. Bot
h conjugates were found to be resistant to oxidation by biological oxidizin
g agents such as O-2, H2O2, and O-2(.-), and the glutathione transferase-ca
talyzed reaction can therefore serve a neuroprotective antioxidant function
. (C) 2000 Academic Press.