Question

A receptor‑ligand complex has a dissociation constant of Kd=20 nM. The rate of receptor‑ligand complex formation with an added ligand concentration of 10 μM is 5×10³ s⁻¹. What is the value of the reverse rate constant, ⁻¹?

Answer 1

The value of the reverse rate constant (k⁻¹) can be calculated using k and Kd by dividing k by Kd.

Step-by-step explanation:

The reverse rate constant, represented as k-1, can be calculated using the equation:

k-1 = k / Kd

Given that the rate of receptor‑ligand complex formation (k) is 5×10³ s⁻¹ and the dissociation constant (Kd) is 20 nM, we can substitute these values into the equation:

k-1 = 5×10³ s⁻¹ / (20 × 10⁻⁹ M)

Converting 20 nM to M:

Kd = 20 × 10⁻⁹ M = 2 × 10⁻⁸ M

Now we can calculate the reverse rate constant:

k-1 = 5×10³ s⁻¹ / 2 × 10⁻⁸ M

k-1 = 2.5 × 10¹¹ s⁻¹ M⁻¹