This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
In glutathione which amino acid is reducing agent? 
Select and explain. 
A. Glutamic acid, B. Cysteine, C. Glycine, D. Alanine
B: Cysteine
Answer: B: Cysteine 
Explanation: -Glutathione is a tripeptide (Gamma Glutamic acid +Cysteine + Glycine)- Gamma glutamyl cysteinyl Glycine-Atypical peptide bond is present between Gamma Glutamic acid and cysteine.