In the double-reciprocal plot of Michaelis-Menten kinetics in the presence and absence of an inhibitor, which of the following are true?

Question

(A) This is a competitive inhibition.

(B) This is an uncompetitive inhibition.

(C) The binding site of the inhibitor is different to that of the substrate.

(D) The number 3 represents the enzymatic reaction without inhibitor. 

(E) The number 1 represents the enzymatic reaction without inhibitor

Please give explanation of correct answer(s)

Answer 1

We can't answer this without seeing the plot or knowing which parameters (Km, Vmax, both, neither) change. If only the slope of the double-reciprocal plot changes, it is competitive inhibition.

If only the y-intercept changes, it is uncompetitive inhibition.

If both the slope and the y-intercept change, it is non-competitive inhibition.