Question

For an enzyme to have high catalytic efficiency it must have low turnover number and low km

Answer 1

Answer:

Turnover Number

kcat is the apparent first-order rate constant for the enzyme-catalyzed reaction at saturating concentrations of substrate.

Explanation:

Catalysis constant (kcat).

The catalysis constant (kcat) refers to the maximum number of substrate molecules converted to products per active site per unit time, or the number of times the enzyme “turns over” per unit time. Therefore the kcat is also called turnover number. For the majority of enzymes, the kcat is ≤103 sec−1, although it can range from 1 to 107 sec−1.

In the Michaelis–Menten mechanism, kcat is equal to k2, the first-order rate constant. In more general situations to which steady-state assumptions adequately apply, kcat is a combination of rate constants from several microscopic steps.