Enzymes are highly efficient catalyst. An enzyme 'catalase' increases the rate of decomposition of H₂O₂(aq) into H₂O(l) and O₂(g) e²⁰ times at 300 K. The activation energy of enzyme catalysed reaction

Question

Enzymes are highly efficient catalyst. An enzyme 'catalase' increases the rate of decomposition of H₂O₂(aq) into H₂O(l) and O₂(g) e²⁰ times at 300 K. The activation energy of enzyme catalysed reaction is 2.0 kcal/mol. Which of the following information(s) is/are correct assuming that the value of pre-exponential factor is unaffected by temperature change or use of catalyst and the activation energy is independent of temperature.

Prashant Kotian · Accepted Answer

Correct answer: A,C,D. The ratio of rates is k_cat / k_uncat = e^{(Ea_uncat - Ea_cat)/RT} = e²⁰. So, (Ea_uncat - 2.0) / (2 × 10⁻³ × 300) = 20, yielding Ea_uncat = 14.0 kcal/mol. Enzyme-catalyzed reactions proceed via an intermediate complex, making them multi-step (complex). As temperature (T) increases, the exponent term (ΔEa / RT) decreases, making the ratio smaller than e²⁰. Therefore, correct answer is A,C,D.

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