Question

Question 14 1 pts What effect is seen on a Lineweaver-Burke graph when a competitive inhibitor is added to an enzymatic reaction? o the line is inversed o the slope of the line changes O neither the y-intercept nor the slope change O both the y-intercept and the slope change O the y-intercepts changes

Answer 1

Lineweaver-Burk plot is a graphical representation of Lineweaver-Burk equation. It is a 1 graph between “ visgi graph between = v/s The Michaelis-Menten equation is given as follows: 1 K. 11 V Vmax [s] Vmax - +- Here, V is the rate of the reaction K. is the Michaelis-Menten constant [S] is the concentration of the substrate Vm, is the maximum rate of the reaction The competitive inhibition is a type of enzyme inhibition in which the inhibitor competes with the substrate. The binding of the inhibitor with the active site of the enzyme blocks the binding site of the enzyme for the substrate. The Lineweaver-Burk plot without any inhibition is shown below:

Slope =Km / max 1/V x-intercept y-intercept 1/ max 1/(S) -1/Km max Vmax is the maximum rate of the reaction and Kn is the amount of the substrate needed to reach half of the Vmax. K. is also the measure of how tightly the enzyme is bound to the substrate.

To overcome the competitive inhibition, more substrate is added to the reaction, hence, the chances of binding of the substrate to the active site of the enzyme increases. As a result, Km of the reaction alters and Vmax of the reaction remains the same in competitive reaction. This is because, increasing of substrate concentration does not increase Vmax Since only K. is increasing, then (-1/K.) (that is, the x-intercept of Lineweaver-Burk plot) will also increase. The value of K. is increasing and the value of Vmax remains the same, hence, the slope of the graph increases. Hence, both the x-intercept and the slope of the line will change. The Lineweaver-Burk plot for competitive inhibition is shown below:

Slope is higher Slope =Km/max No inhibitor 1/V X-intercept y-intercept 1/max 1/(S) -1/Km Increase in x-intercept Hence correct option is 2nd , that is slope of the line changes.