Glutathione is composed of:

Ans. (d) All of the aboveRef: Harpers Biochemistry 30th ed. pg. 22-23, 748* Glutathione (GSH) is a tripeptide with a gamma peptide linkage between the amine group of cysteine (which is attached by normal peptide linkage to a glycine) and the carboxyl group of the glutamate side chain.* It is an antioxidant, preventing damage to important cellular components caused by reactive oxygen species such as free radicals and peroxides.