In a Lineweaver-Burk plot, where do the lines intersect during competitive inhibition?

In a Lineweaver-Burk plot, which is a double reciprocal plot of enzyme kinetics, the representation of competitive inhibition shows that the lines intersect on the Y-axis.

During competitive inhibition, the inhibitor competes with the substrate for the active site of the enzyme. This competition modifies the apparent affinity of the enzyme for the substrate, which is reflected in the plot. As competitive inhibitors increase the Michaelis-Menten constant (Km) but do not affect the maximum velocity (Vmax) of the enzyme, the slope of the line becomes steeper while the Y-intercept remains the same.

The Y-intercept of the Lineweaver-Burk plot is equal to 1/Vmax, which means that since Vmax is constant in competitive inhibition, the Y-intercept does not change regardless of the presence of the inhibitor. However, the X-intercept, which is related to -1/Km, moves closer to the origin with increasing concentrations of the competitive inhibitor since it effectively raises Km. This results in lines that intersect at the Y-axis, showcasing that while the slope changes with different levels of inhibition, the maximum rate of reaction remains unaltered.

Understanding this intersection point is vital because it visually demonstrates how competitive inhibitors affect enzyme activity in