Question

Which of the following is not an amino acid?

• A. Glycine
• B. Alanine
• C. Histidine
• D. Benzidine

Answer 1

Answer: (D)

Benzidine is not an amino acid but it is a aromatic amine. Its molecular formula is $C_{12}{H}_{12}{N}_2$.
Its IUPAC name is $4,4^{\prime }$-diaminobiphenyl, which is used as part of a test for cyanide and also in the synthesis of dyes.