Enzyme Inhibition Kinetics

inhibition type

competitive

uncompetitive

mixed

self inhibited

plot type

Lineweaver-Burk

Michaelis-Menten

inhibitor concentration (mol/L)

2

The rate of substrate disappearance

(-

rate

s

)

depends on the substrate and inhibitor concentrations as well as the parameters

V

max

,

K

M

, and

K

I

. The Lineweaver–Burk plot of

(-1/rate)

versus (

1/substrateconcentration

) is a straight line (except for the self-inhibited case). Increasing the inhibitor concentration increases the intercept for competitive inhibition (with slope not changing), but increases the slope for uncompetitive inhibition leaves the intercept unchanged. Increasing the inhibitor concentration increases both the slope and intercept for noncompetitive or mixed inhibition. The effect of changing inhibitor concentration can also be seen on the Michaelis–Menten plot, which plots

(-1/rate)

versus (

1/substrateconcentration

). When a reaction is self inhibiting, the substrate concentration (

x

-axis) is the inhibitor concentration, so the slider is disabled.