Question

What does it mean when Kcat for an enzyme is 10^4 sec^-1 and Km is 10^-2 micromolar

Answer 1

the rate of catalysis is equal to Kcat .so the rate of catalysis of enzyme is 10^4 sec ^-1 . Enzyme catalysis is the increase in the rate of a chemical reaction by the active site of a protein.

The relationship between rate of reaction and concentration of substrate depends on the affinity of the enzyme for its substrate. This is usually expressed as the Km (Michaelis constant) of the enzyme, an inverse measure of affinity.Km is the concentration of substrate which permits the enzyme to achieve half Vmax. In this question Km value is 10^-2 micromolar which means the substrate attains half Vmax at 10^-2 molar .  

The rate of reaction when the enzyme is saturated with substrate is the maximum rate of reaction, is called Vmax.