Proteins can be denatured by all the following except __________.

• A. organic solvents
• B. strong acids
• C. heat
• D. enzymatic hydrolysis

Answer: (D)

Verified step by step guidance

1. Understand the concept of protein denaturation: Protein denaturation refers to the process where a protein loses its native structure due to external stress or agents, such as heat, strong acids, or organic solvents. This disrupts the non-covalent interactions (e.g., hydrogen bonds, ionic bonds, hydrophobic interactions) that maintain the protein's structure.
2. Review the listed options: Organic solvents, strong acids, and heat are all common agents that can denature proteins by disrupting their secondary, tertiary, or quaternary structures. Enzymatic hydrolysis, however, is a different process.
3. Clarify enzymatic hydrolysis: Enzymatic hydrolysis involves breaking down proteins into smaller peptides or amino acids using enzymes like proteases. This is not denaturation but rather a chemical cleavage of peptide bonds, which is distinct from the structural disruption caused by denaturation.
4. Compare enzymatic hydrolysis to denaturation: Denaturation alters the protein's structure without breaking peptide bonds, whereas enzymatic hydrolysis breaks peptide bonds to degrade the protein into smaller components.
5. Conclude why enzymatic hydrolysis is the correct answer: Since enzymatic hydrolysis does not cause denaturation but instead chemically breaks down the protein, it is the exception among the listed options.