Two methyl groups of α-L-glutamyl-α-aminoisobutyric acid which were equivalent in the acidic solution became unequivalent in the aqueous and basic solutions. Such an unequivalence of two methyl groups was not manifested in the cases of γ-L-glutamyl-α-aminoisobutyric acid, α- and γ-L-glutamylisopropylamide, N-glutaryl-α-aminoisobutyric acid and N-glutarylisopropylamine.
