Which of the Following Is Correct Concerning the Dissociation Constant

Multiple Choice

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.