Cho các chất sau:
(1) H2N-CH2-CO-NH-CH(CH3)-COOH
(2) H2N-CH(CH2-C6H5)-CO-NH-CH2-COOH
(3) H2N-CH2-CH2-CO-NH-CH2-COOOH
(4) H2N-CH2-COOH
(5) H2N-CH(CH3)-CO-NH-CH2-COOH
(6) H2N-CH2-CO-NH-CH2-COOH
Đăng ký qua Google: