Proteins are more readily attacked by digestive enzymes when they're

• A. Native
• B. Denatured
• C. Gelatinised
• D. Coagulated

Answer: (B)

Proteolytic enzymes can only cut peptide bonds that are accessible. In native, folded proteins, many of the peptide bonds are tucked inside the structure and shielded from enzymes. When a protein is denatured, it loses its folded shape and unfolds, exposing more peptide bonds and increasing surface area for the enzymes to act on. This makes digestion faster because the proteases can bind and hydrolyze the bonds more readily.

Coagulation tends to form a tighter, networked structure that can actually reduce access to bonds, and native (unfolded) proteins are less accessible than denatured ones. Gelatinisation is mainly a starch-related process, not the mechanism that makes proteins more susceptible to proteases. So, denatured proteins are the ones more readily attacked by digestive enzymes.