Mixed inhibition on a Lineweaver–Burk plot
On a Lineweaver–Burk plot, the line for an inhibited reaction crosses the uninhibited line to the left of the y-axis and above the x-axis. Which type of inhibition is this?
Answer C: explanation for every choice
Competitive inhibition lines cross on the y-axis, because Vmax is unchanged.
Uncompetitive inhibition gives parallel lines, because Km and Vmax fall by the same factor.
Correct. Mixed inhibition lowers Vmax and changes Km, so the lines cross off both axes. Crossing above the x-axis means the inhibitor prefers free enzyme, so apparent Km increases.
Irreversible inhibition removes active enzyme, lowering Vmax with Km unchanged. On a plot it resembles noncompetitive inhibition, with lines crossing on the x-axis.
Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID bb4.