Glutathione is a tripeptide composed of which amino acids?

• A. Glutamate, Cysteine, Histidine
• B. Glutamate, Cysteine, Glycine
• C. Glutamate, Glycine, Alanine
• D. Glutamate, Cysteine, Methionine

Answer: (B)

Glutathione is a short peptide made from the amino acids Glutamate, Cysteine, and Glycine in that order, connected as a gamma-glutamyl–cysteinyl–glycine tripeptide. The cysteine provides the reactive thiol group that gives glutathione its antioxidant power, while glycine completes the trio. Among the options, only Glutamate, Cysteine, and Glycine match this exact composition, whereas the other lists replace one of the needed amino acids with histidine, alanine, or methionine, so they don’t form glutathione.