Since, Vmax is reached in the presence of an infinite amount of substrate and is therefore impossible to determine Km and Vmax from a hyperbolic graph. Due to this issue the equation of Michaelis-Menten was converted into an equation of straight lines using Lineweaver along with Burk.
The lineweaver-burk graph (or the double reciprocal plot) is a graph of the Lineweaver Burk equation of enzyme kinetics. It was first described in 1934 by Hans Lineweaver and Dean Burk in 1934. The plot is a reinterpretation from the Michaelis-Menten formula and is depicted asfollows:
where V is the reaction velocity (the reaction rate), Km is the Michaelis–Menten constant, Vmax is the maximum reaction velocity, and [S] is the substrate concentration.
It is straight lines that has the line’s intercept on the y-axis being equal to 1Vmax and the intercept on the x-axis is equal to Km/Vmax. The line’s slope will be Km/Vmax.
Vmax and Km are determined by measuring the V0 in different concentrations of substrate. A double reciprocal or Lineweaver-Burk graph of 1/V0 and the ratio 1/[S] can be constructed.
Reversible enzyme inhibitors are classified as competitive or not, and are distinguished by an Lineweaver-Burk chart. It’s a good method to determine how inhibitors bind to an enzyme. It is possible to detect competitive inhibition through a Lineweaver-Burk graph in the event that V0 is determined at different concentrations of substrate with a predetermined amount of inhibitor.
An inhibitor that is competitive enhances that line’s slope in the Lineweaver-Burk plot. It also affects the angle on the x-axis (since Km is increased) However, it keeps the intercept on y-axis unaltered (since Vmax remains constant). Noncompetitive inhibition may also be detected on a Lineweaver Burk plot because it increases that slope of the experiment line, and alters direction of the intercept along the y-axis (since Vmax decreases) however, it does not alter the x-axis intercept unaltered (since Km is constant).
Uses of Lineweaver–Burk Plot
- The method is used to define crucial terms in enzyme kinetics like Km and Vmax prior to the widespread access to powerful computers and non-linear regression software.
- Provides a brief, visual glimpse of the various types of inhibition of enzymes.