How do you determine inhibition from a Lineweaver-Burk plot?
As shown in Figure 13.14, when we display kinetic data using as a Lineweaver-Burk plot it is easy to determine which mechanism is in effect. For example, an increase in slope, a decrease in the x-intercept, and no change in the y-intercept indicates competitive inhibition.
How do you calculate Vmax and Km?
This is usually expressed as the Km (Michaelis constant) of the enzyme, an inverse measure of affinity. For practical purposes, Km is the concentration of substrate which permits the enzyme to achieve half Vmax….plotting v against v / [S] gives a straight line:
- y intercept = Vmax.
- gradient = -Km.
- x intercept = Vmax / Km.
How do you find Vmax and Km from a graph?
From the graph find the maximum velocity and half it i.e. Vmax/2. Draw a horizontal line from this point till you find the point on the graph that corresponds to it and read off the substrate concentration at that point. This will give the value of Km.
How do you calculate Km and Vmax?
How do you calculate Vmax and Km from Lineweaver-Burk plot?
Ease of Calculating the Vmax in Lineweaver-Burk Plot Next, you will obtain the rate of enzyme activity as 1/Vo = Km/Vmax (1/[S]) + 1/Vmax, where Vo is the initial rate, Km is the dissociation constant between the substrate and the enzyme, Vmax is the maximum rate, and S is the concentration of the substrate.
What does the slope of a Lineweaver-Burk plot represent?
On the graph, the x-intercept can be used to determine the Michaelis constant, the y-intercept can be used to determine the maximal velocity and the slope represents the ratio of the Michaelis constant to the maximal velocity.
What does the Lineweaver Burk plot tell you?
The Lineweaver–Burk plot was widely used to determine important terms in enzyme kinetics, such as Km and Vmax, before the wide availability of powerful computers and non-linear regression software. The y-intercept of such a graph is equivalent to the inverse of Vmax; the x-intercept of the graph represents −1/Km.
What is the Lineweaver-Burk equation?
Created by Hans Lineweaver and Dean Burk in 1934, the Lineweaver-Burk equation is a modification of the Michaelis-Menton Equation dealing with enzyme kinetics; allowing it to be represented in graphical-linear form with respect to time.
How do you use the Lineweaver Burk plot?
The Lineweaver–Burk plot puts 1/ [S] on the x-axis and 1/V on the y-axis. When used for determining the type of enzyme inhibition, the Lineweaver–Burk plot can distinguish competitive, pure non-competitive and uncompetitive inhibitors. The various modes of inhibition can be compared to the uninhibited reaction.
What is the value of km V Max in Lineweaver Burk equation?
In the equation’s markup, KM V max K M V max is the slope of the equation with intercepts of 1 V max 1 V max on the vertical axis and − 1 KM – 1 K M on the horizontal axis. The Lineweaver-Burk equation is: 1/V 0 = Inverse Velocity in seconds-liters per mole (s·L/mol), where v0 v 0 is the reaction rate
Why is the Lineweaver Burk plot used for enzyme kinetics?
While the Lineweaver-Burk is useful for determining important variables in enzyme kinetics, it is prone to error. The y-axis of the plot takes the reciprocal of the rate of reaction, meaning small errors in measurement are more noticeable.