A chemist at a pharmaceutical company is measuring

Chapter , Problem 15.40

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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 1.50 * 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 and for the Bprotein binding reaction. Assuming that the drug that binds more strongly will be more effective, which drug is the better choice for further research?