Details

Reaction Pathways

values come from respective reaction coefficients

represents the concentration of an enzyme-substrate complex

represents the concentration of an enzyme-inhibitor complex

represents the concentration of an enzyme-inhibitor-substrate complex

is the total enzyme concentration

,

,

.

The Linweaver–Burk method in a method of linearizing experimental data. The slope and intercept from experimental data can be used to determine , , and from plotted data.

The line is given by

,

where is the slope, is the intercept, and is the intercept (the value of when ).

Competitive Inhibition: The inhibitor competes with the substrate for the enzyme to form an inactive complex.

(1) (2) (3) (4) (inactive) (5)

,

,

,

,

.

Uncompetitive (Anti-Competitive) Inhibition: The inhibitor binds to the enzyme-substrate complex forming an inhibitor-enzyme-substrate complex.

(1) (2) (3) (4) (inactive) (5)

,

,

,

,

.

Noncompetitive Inhibition (Mixed Inhibition): Mixed inhibition is most commonly seen for enzymes with two or more substrates. The inhibitor can bind to the enzyme or enzyme-substrate complex. The substrate can also bind to the inhibitor-enzyme complex.

(1) (2) (inactive) (3) (4) (inactive) (5) (inactive)

,

,

,

,

.

Substrate Inhibition: In the case of uncompetitive inhibition, the inhibitor ties up the enzyme-substrate complex to form an inactive substrate-enzyme-substrate complex.

(1) (2) (3) (4) (inactive) (5)

,

;

this plot in not linear because the intercept depends on the substrate concentration .

Reference

[1] H. S. Fogler, Essentials of Chemical Reaction Engineering, 1st ed., Upper Saddle River, NJ: Pearson Higher Education, 2010 pp. 364–370.