Question

Glutathione can be an example of which one of the following?

• A. Lipids
• B. Carbohydrate
• C. Protein
• D. Peptide

Hint:

Glutathione (GSH): Natural antioxidant TRIPEPTIDE ($\gamma$-Glu-Cys-Gly). Maintains cellular redox balance via Glutathione Peroxidase/Reductase.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Glutathione (GSH) is a low-molecular-weight biological antioxidant tripeptide containing an atypical $\gamma$-glutamyl linkage.
Key Formula or Approach:
\[ \text{Glutathione (GSH)} = \gamma\text{-L-Glutamyl-L-Cysteinyl-Glycine} \]

Step 2: Detailed Explanation:
Glutathione (GSH):
- A non-protein tripeptide composed of three amino acids: Glutamate, Cysteine, and Glycine ($\gamma$-L-glutamyl-L-cysteinylglycine).
- It features an atypical isopeptide bond between the $\gamma$-carboxyl group of glutamate's side chain and the $\alpha$-amino group of cysteine, protecting it from degradation by standard cellular peptidases.
- The active sulfhydryl ($-SH$) group of cysteine acts as the cell's principal endogenous reducing agent and free-radical scavenger.

Step 3: Final Answer:
Therefore, Glutathione is an example of a Peptide, corresponding to option (D).