Question

If a Lineweaver-Burk plot was made for an enzyme-catalyzed reaction, both with and without a competitive inhibitor present, what difference would be seen?

a) Parallel lines
b) Intersecting lines
c) Shift along the x-axis
d) Shift along the y-axis

Answer 1

The presence of a competitive inhibitor in an enzyme-catalyzed reaction will cause the Lineweaver-Burk plot to show intersecting lines, indicating that the Km has increased but the Vmax remains unchanged.

Step-by-step explanation:

The Lineweaver-Burk plot is a graphical representation used to illustrate the kinetics of enzyme-catalyzed reactions. When a competitive inhibitor is present, it will bind to the active site of the enzyme, competing with the substrate. This results in an increase in the apparent Michaelis constant (Km), which is seen as a shift along the x-axis, because more substrate is needed to achieve half-maximal velocity. However, Vmax, the maximum reaction velocity, remains unchanged because the inhibitor can be outcompeted by high substrate concentrations. Therefore, if a Lineweaver-Burk plot is made with and without a competitive inhibitor, the lines will intersect on the y-axis, indicating that the Vmax is the same for both reactions but the Km has increased in the presence of the inhibitor.