Editing Lineweaver–Burk plot (section)

==Applications==
[[File:Inhibition-types.jpg|thumb|upright=2|Effects of different types of inhibition on the double-reciprocal plot]]
When used for determining the type of enzyme inhibition, the Lineweaver–Burk plot can distinguish between [[Competitive inhibition|competitive]], pure [[Non-competitive inhibition|non-competitive]] and [[Uncompetitive inhibition|uncompetitive]] inhibitors. The various modes of inhibition can be compared to the uninhibited reaction.

=== Competitive inhibition ===
The apparent value of <math>V</math> is unaffected by competitive inhibitors. Therefore competitive inhibitors have the same intercept on the ordinate as uninhibited enzymes.

Competitive inhibition increases the apparent value of <math>K_\mathrm{m}</math>, or lowers substrate affinity.  Graphically this can be seen as the inhibited enzyme having a larger intercept on the abscissa.

=== Pure non-competitive inhibition ===
With pure noncompetitive inhibition the apparent value of <math>V</math> is decreased. This can be seen on the Lineweaver–Burk plot as an increased ordinate intercept with no effect on the abscissa intercept <math>-1/K_\mathrm{m}</math>, as pure noncompetitive inhibition does not effect substrate affinity.

=== Mixed inhibition ===
Pure noncompetitive inhibition is rare, and mixed inhibition is much more common. In mixed inhibition the apparent value of <math>V</math> is decreased, and that of <math>K_\mathrm{m}</math> is changed—usually increased, meaning that the affinity usually decreases with mixed inhibition.

Cleland recognized that pure noncompetitive inhibition was very rare in practice, occurring mainly with effects of protons and some metal ions, and he redefined ''noncompetitive'' to mean ''mixed''.<ref>{{cite journal | doi= 10.1016/0926-6569(63)90226-8 | journal =Biochim. Biophys. Acta  | volume = 67 | number = 2 | pages = 173–187 | title = The kinetics of enzyme-catalyzed reactions with two or more substrates or products: II. Inhibition: Nomenclature and theory | author = Cleland, W. W.}}</ref> Many authors have followed him in this respect, but not all.

=== Uncompetitive inhibition ===
The apparent value of <math>V</math> decreases with uncompetitive inhibition, with that of  <math>V/K_\mathrm{m}</math>. This can be seen on the Lineweaver–Burk plot as an increased intercept on the ordinate with no change in slope.

Substrate affinity increases with uncompetitive inhibition, or lowers the apparent value of <math>K_\mathrm{m}</math>. Graphically uncompetitive inhibition can be identified in the plot parallel lines for the different concentrations of inhibitor..