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Biochemistry A. For a Michaelis-Menten reaction, k 1 = 7 x 10 7 per molar per se

ID: 950247 • Letter: B

Question

Biochemistry

A. For a Michaelis-Menten reaction, k1 = 7 x 107 per molar per second; k2 = 1 x 103 per second; and k3 = 2 x 104 per second. Given this information, what is the value of Km, the Michaelis-Menten constant. Report your answer in terms of micromolar to the nearest ones. Use the convention followed in class to characterize rate constants for forward and reverse steps in an enzyme-catalyzed reaction.

B. For a Michaelis-Menten reaction, k1 = 7 x 10^7 per molar per second; k2 = 1 x 10^3 per second; and k3 = 2 x 10^4 per second. Given this information, what is the value of Kd, the dissociation constant for the enzyme-substrate complex? Report your answer in terms of micromolar to the nearest ones.

Explanation / Answer

To obtain the value of Km:

Km = (k2 + k3) / k1

Km = (1 x 103 1/s + 2 x 104 1/s) / (7 x 107) 1/M-s

Km = 3 x 10-4 M = 300 micromolar

To obtain Kd:

Kd = k2 / k1

Kd = (1 x 103)1/s / (7 x 107)1/M-s = 1 x 10-4 M = 100 micromolar