Which of the following is correct concerning the dissociation constant, K_d, of a drug X? A) A larger K_d implies tighter target to drug binding. B) The K_d corresponds to the concentration of drug that binds to 90% of the target. C) The K_d can be determined from the simple saturation curve of a binding reaction. D) The apparent K_d increases as the K_M of the true substrate increases. E) None of the answers is correct.

Question

Quizplus · Accepted Answer

The dissociation constant, $K_d$, is determined from the saturation curve of a binding reaction, reflecting the concentration at which half of the available binding sites are occupied by the drug. This makes option C correct. Options A, B, and D are incorrect as a larger $K_d$ indicates weaker binding, $K_d$ corresponds to the concentration at which 50% (not 90%) of the target is bound, and the apparent $K_d$ is not directly influenced by the $K_m$ of a substrate in the context provided.

Which of the Following Is Correct Concerning the Dissociation Constant