Which factor can denature enzymes and reduce activity?

• A. Low temperatures or neutral pH.
• B. Enzymes are unaffected by temperature and pH.
• C. High temperatures or extreme pH can denature enzymes and reduce activity.
• D. Only solvents can affect enzymes, not temperature or pH.

Answer: (C)

Enzymes rely on their specific folded shape to place the active site correctly for catalysis. When environmental conditions disrupt the bonds that hold that shape, the enzyme can unfold or misfold, reducing or eliminating activity. High temperatures increase molecular motion enough to break hydrogen bonds and other interactions that stabilize the structure, causing denaturation. Extreme pH levels change the charge states of amino acids, breaking ionic and hydrogen bonds and altering the active site geometry. As a result, the enzyme loses its functional shape and activity drops. Low temperatures or near-neutral pH don’t denature proteins; they may slow reactions but keep the structure intact. So, high temperatures or extreme pH can denature enzymes and reduce activity.