Lineweaver-Burk

[406003397]

In enzyme kinetics, how do competitive and non-competitive inhibitors affect the reaction rate, and how can these effects be distinguished graphically using Lineweaver-Burk plots?

[305878818]

In enzyme kinetics, competitive inhibitors compete with the substrate for binding to the active site of the enzyme, thus increasing the apparent KM (Michaelis constant) value without affecting the maximum reaction rate (Vmax). This leads to a decrease in substrate binding efficiency, resulting in a higher substrate concentration being required to achieve half-maximal velocity. Conversely, non-competitive inhibitors bind to the enzyme at a site distinct from the active site, altering the enzyme's conformation and reducing its catalytic activity. Non-competitive inhibitors decrease the maximum reaction rate (Vmax) without affecting the apparent KM value. Graphically, these effects can be distinguished using Lineweaver-Burk plots: competitive inhibition results in lines that intersect on the y-axis (1/Vmax), while non-competitive inhibition produces intersecting lines on the x-axis (-1/KM), reflecting distinct changes in the kinetic parameters of the reaction.

[Sarah Egan 3A]

Competitive inhibitors affect the Michaelis constant but not the maximum reaction rate, which would look like intersecting lines with different slopes on Lineweaver-Burk plots. Non-competitive inhibitors change the maximum reaction rate only which looks like lines with the same slope but different y-intercepts on Lineweaver-Burk plots.