Question

The Km of an enzyme is

• A. One half of the Vmax
• B. A dissociation constant
• C. The substrate concentration that gives maximal velocity
• D. The substrate concentration that gives half maximal velocity

Answer 1

Answer: (D)

This value is numerically equal to the substrate concentration at which half of the enzyme molecules are associated with the substrate. Km value is an index of the affinity of the enzyme for its particular substrate. This is usually expressed as the Km (Michaelis constant) of the enzyme, an inverse measure of affinity.