Question

The following value is a measure of an enzyme's affinity for its substrate:

A) Vmax

B) kcat

C) Km

D) A, B, and C

When a substrate concentration is MUCH greater than Km, the rate of catalysis is almost equal to:

A) Kd

B) kcat

C) Vmax

D) none of the above

Answer 1

1)

C) Km is right option.

The Michaelis constant, Km is a measure of an enzyme's affinity for its substrate.

If Km is lower, the more effective the enzyme is at low substrate concentrations and if Km is higher, the less effective the enzyme is.

1)

C) Vmax is correct option.

Michaelis-Menten equation: V_o = V_max [S]/[S] + Km states, at high substrate concentration, when [S] is much greater than KM,

V₀ = Vmax

The rate is maximal and independent of substrate concentration.