Question

A chemist at a pharmaceutical company is measuring equilibrium constants for reactions in which drug candidate molecules bind to a protein involved in cancer. The drug molecules bind the protein in a 1:1 ratio to form a drug-protein complex. The protein concentration in aqueous solution at 25 ∘C is 1.88×10⁻⁶ M . Drug A is introduced into the protein solution at an initial concentration of 2.00×10⁻⁶M. Drug B is introduced into a separate, identical protein solution at an initial concentration of 2.00×10⁻⁶M. At equilibrium, the drug A-protein solution has an A-protein complex concentration of 1.00×10⁻⁶M, and the drug B solution has a B-protein complex concentration of 1.40×10⁻⁶M.

Part A: Calculate the Kc value for the A-protein binding reaction. Express your answer using two significant figures.

Part B: Calculate the Kc value for the B-protein binding reaction. Express your answer using two significant figures.

Answer 1