Question

During deturation which bonds in protein structure are NOT broken:

• A. Disulphide bonds
• B. Hydrogen bonds
• C. Ionic bonds
• D. Peptide bonds

Hint:

Deturation affects higher-order structures ($2^\circ, 3^\circ, 4^\circ$) while keeping the primary structure ($1^\circ$ peptide bonds) intact.
Proteolysis is required to break peptide bonds, which is distinct from deturation.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
The question asks to identify which chemical bonds remain intact during protein deturation.

Step 2: Key Formula or Approach:
Protein structure is organized into four levels:
• Primary structure: Sequence of amino acids linked covalently by peptide bonds.

• Secondary, Tertiary, Quaterry structures: Maintained by non-covalent interactions (hydrogen bonds, ionic bonds, hydrophobic interactions) and covalent disulfide bridges.
Deturation disrupts higher-order structures without breaking primary covalent backbone bonds.

Step 3: Detailed Explation:

• Definition of Deturation: Deturation refers to the unfolding of a protein's tive three-dimensiol tertiary or secondary structure under stress conditions such as high heat, extreme pH, organic solvents, or chaotropic agents (e.g., urea, guanidinium chloride).

• Bonds Affected: Deturation disrupts weak non-covalent interactions (hydrogen bonds, ionic interactions/salt bridges, van der Waals forces) and can reduce disulfide linkages if reducing agents are present.

• Preservation of Peptide Bonds: The covalent peptide bonds (amide linkages) forming the primary backbone of the polypeptide chain are robust and require enzymatic cleavage or harsh chemical acid/base hydrolysis to break. Thus, primary structure remains completely intact after deturation.

Step 4: Fil Answer:
Peptide bonds holding together the primary amino acid sequence are NOT broken during protein deturation.