The Glutathione structure (γ-L-Glutamyl-L-cysteinylglycine) is unique due to the gamma-peptide bond between the amine group of cysteine and the side-chain carboxyl group of the glutamate residue. This specific linkage protects the molecule from degradation by most intracellular peptidases. The presence of a chemically active thiol (-SH) group on the cysteine residue allows Glutathione to serve as a high-capacity electron donor, enabling the neutralization of reactive oxygen species (ROS) and the maintenance of other antioxidants like vitamins C and E in their active forms.