The glutathione analogue gamma-(H-Glu-OH)-Cys-Cys-OH (5), containing the 8-
membered disulfide ring -Cys-Cys replacing the native -Cys-Gly fragment, ha
s been synthesized and characterized together with its reduced dithiol form
gamma-(H-Glu-OH)-Cys-Cys-OH (6).