Problem: 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 oC is 1.72×10−6 M . Drug A is introduced into the protein solution at an initial concentration of 2.00 10-6 M. Drug B is introduced into a separate, identical protein solution at an initial concentration of 2.00 10-6 M. At equilibrium, the drug A-protein solution has an A-protein complex concentration of 1.00 10-6 M, and the drug B solution has a B-protein complex concentration of 1.40 10-6 M.Calculate the Kc value for the A-protein binding reaction.

FREE Expert Solution

We have to calculate the equilibrium constant (Kc) for the reaction of binding of a drug “A” with a protein.


We have the information that the drug A form a 1:1 complex with the protein. The equation for the reaction is:

A + Protein A-Protein complex

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Problem Details

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 oC is 1.72×10−6 M . Drug A is introduced into the protein solution at an initial concentration of 2.00 10-6 M. Drug B is introduced into a separate, identical protein solution at an initial concentration of 2.00 10-6 M. At equilibrium, the drug A-protein solution has an A-protein complex concentration of 1.00 10-6 M, and the drug B solution has a B-protein complex concentration of 1.40 10-6 M.

Calculate the Kc value for the A-protein binding reaction.

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