BIOCHEMISTRY-Reaction Velocity Question

Question

For an enzyme that obeys Michaelis-Menten kinetics, what is the reaction velocity, V, observed at the following substrate concentrations?

Express the result as a percentage of V_max.

(a) If [S] = K_M, then V/V_max = ___% .

(b) If [S] = 0.100K_M, then V/V_max = __% .

Answer 1

v = V_max [S] / K_m + [S] ... Michaelis Menton equation

(a) If [S] = K_m

v = V_max (K_m) / K_m + K_m

v = V_max (K_m) / 2K_m

v = V_max / 2

v = 1/2 V_max = 50% V_max

(b) if [S] = 0.1 K_m

v = V_max (0.1 K_m) / K_m + 0.1 K_m

v = V_max (0.1K_m) / 1.1K_m

v = 0.091V_max = 9.1% V_max