Question

Which amino acid is responsible for forming disulfide bridges in a protein structure?

• A. Glycine
• B. Cysteine
• C. Lysine
• D. Alanine

Hint:

Two cysteine residues → Oxidation → Disulfide bond (S–S)

Answer 1

The Correct Option is B

Concept:
Proteins are stabilized by several types of chemical interactions such as hydrogen bonds, ionic interactions, hydrophobic interactions, and disulfide bonds. These disulfide bonds are important for maintaining the three-dimensional structure of proteins.
Step 1:Understanding disulfide bridges.
A disulfide bridge (–S–S–) is a covalent bond formed between two sulfur atoms of amino acids.
Step 2:Identifying the amino acid involved.
The amino acid cysteine contains a sulfhydryl group (–SH). When two cysteine residues come close together during protein folding, their sulfhydryl groups oxidize and form a disulfide bond.
Step 3:Role in protein structure.
Disulfide bonds help stabilize:

• Tertiary protein structure
• Quaternary protein structure
• Extracellular proteins such as antibodies and hormones

Conclusion:
Therefore, the amino acid responsible for forming disulfide bridges is cysteine.