What is the difference between a MichaelisMenten graph and a

What is the difference between a Michaelis-Menten graph and a Lineweaver-Burk plot? Why are both used?

Solution

Both Michaelis-Menten kinetics & Lineweaver-Burk plot are well known models of enzyme kinetics,

Michaelis-Menten kinetics:

It describes the rate of an enzyme reaction by relating reaction rate to substrate concentration.

V = V_max [s]/K_M + [s]

Determination of K_M and V_max values required algebraic manipulation of the basic Michaelis-Menten equation. The value for V_max forms a horizontal asymptote on the graph. K_M can be determined by the x-value at which Vmax is 1/2 its value. K_M is the concentration of substrate at V_max/2, it is likewise impossible to determine an accurate value of K_M.

Lineweaver-Burk Plot:

V_max can be accurately determined if the Michaelis-Menten equation is transformed into one that gives a straight-line plot. Taking the reciprocal of both sides of equation.

V = V_max [s]/K_M + [s]………………………………. Michaelis-Menten kinetics

1/V= 1/_Vmax + K_M/V_max X 1/[s]………………... Lineweaver-Burk Plot

It is also called as reciprocal plot.

This gives a straight line with an intercept of 1/Vmax and a slope of KM/Vmax.

The Lineweaver-Burk Plot is useful in determining the mechanism by which an enzyme reaction occurs. A sequential mechanism produces intersecting lines on the Lineweaver-Burk Plot.