Enzyme reaction rates are increased by increasing temperatures until they reach the point of denaturation at

Enzyme reaction rates are increased by increasing temperatures until they reach the point of denaturation at

• A. 40-60°C
• B. 25-35°C
• C. 100°C
• D. 37°C

Answer: (A)

Enzyme activity rises with temperature because hotter molecules collide more energetically, speeding up reactions. But that only holds until the protein begins to lose its shape. Denaturation happens when heat disrupts the noncovalent bonds that hold an enzyme’s folded structure, changing or destroying the active site and drastically reducing or stopping catalysis. For many enzymes, the structural integrity starts to fail around 40–60°C, so reaction rates climb with temperature up to that range and then fall off as denaturation occurs. At 37°C, human enzymes are often near their typical operating range; at 25–35°C the rate is slower due to less kinetic energy; at 100°C denaturation is rapid and complete. Thus, the temperature range where denaturation begins for many enzymes is about 40–60°C.

Enzyme activity rises with temperature because hotter molecules collide more energetically, speeding up reactions. But that only holds until the protein begins to lose its shape. Denaturation happens when heat disrupts the noncovalent bonds that hold an enzyme’s folded structure, changing or destroying the active site and drastically reducing or stopping catalysis. For many enzymes, the structural integrity starts to fail around 40–60°C, so reaction rates climb with temperature up to that range and then fall off as denaturation occurs. At 37°C, human enzymes are often near their typical operating range; at 25–35°C the rate is slower due to less kinetic energy; at 100°C denaturation is rapid and complete. Thus, the temperature range where denaturation begins for many enzymes is about 40–60°C.