Parallel lines on a Lineweaver-Burk plot indicate
(I) an increase in K_M.
(II) decrease in K_M.
(III) decrease in V_max.
(IV) uncompetitive inhibition.

Question

Quizplus · Accepted Answer

Parallel lines on a Lineweaver-Burk plot indicate either an increase (I) or decrease (II) in the value of the slope (K_M), but they do not indicate anything about the value of V_max. These types of parallel lines can be seen in noncompetitive inhibition or when the enzyme is allosterically regulated by the inhibitor. Therefore, option IV (uncompetitive inhibition) can be ruled out. Option B is incorrect because it includes choice III, which is not always true for all situations that result in parallel lines.

Parallel Lines on a Lineweaver-Burk Plot Indicate