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GATE 2026 BT – Question 32

Fundamentals of Biological Engineering · Bioreaction Engineering: Rate law, zero and first order kinetics, Michaelis-Menten kinetics and enzyme inhibition · 1 mark · Numerical answer

You are characterizing a new enzyme isolated and purified in the laboratory. If the maximum velocity of the enzyme is 1800 $\mu$moles L$^{-1}$ min$^{-1}$ and the total concentration of the enzyme in the reaction mixture is 1.5 $\mu$M, then the turnover number of the enzyme is _______ s$^{-1}$. (answer in integer)

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Correct answer: 20

Explanation

The turnover number is $k_{cat} = \frac{V_{max}}{[E]_0}$. $V_{max} = \frac{1800}{60} = 30\ \mu M\,s^{-1}$, so $k_{cat} = \frac{30}{1.5} = 20$ s$^{-1}$.