This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Proteins and Amino Acids, Subject name: Biochemistry
[{'content': 'Glutathione is composed of: \nSelect and explain. \nA. Glycine, B. Cycteine, C. Glutamate, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: 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.', 'role': 'assistant'}]