Finding Michaelis-menten constant and Vmax

[babbagee]

Ok, here is the problem

A single-substrate enzyme catalyzed reaction was investigated in the presence of 1.0 mM inhibitor as well as in the absence of inhibitor, the intial substrate concentration being constant throughout. The following results were obtained:

----------------intial velocity (uM/min) that is micro Molar per min
(mM)--------=0------------ = 1.0mM
5.0-------------161-------------111
6.67------------194-------------141
10.00-----------263-------------183
20.00-----------400-------------279
50.00-----------576-------------399

Determine the type of inhibition exhibited by I and caluclate the values of Km apparent and Vmax apparent in the presence of 3.0mM inhibitor.

Ok i made a Linewaver-burk plot, and it looks seems that the inhibitor is a noncompetative inhibitor because it does not change Km but it does change Vmax, but the part i am having trouble with is how to calculate Km apparent and how to calculate Vmax apparent. Will that just be the Km apparent be just the x-intercept of the Lineweaver-burk plot, and Vmax apparent be the y-intercept of the second line where 1.0mM inhibitor was used. I am not sure though because it wants these values at 3.0mM. So can some one help me out please.

Thanks

 

[Nino MMP]

for the help.Yes, the Km apparent would be the x-intercept of the Lineweaver-Burk plot and Vmax apparent would be the y-intercept of the line with 1.0mM inhibitor, but you will need to extrapolate the data to get the values at 3.0mM inhibitor. To do this, you can use a linear regression on the data points and then use the equation to calculate the values at 3.0mM.

 

[Blueshift5]

for sharing your results and question. Based on the data provided, it does appear that the inhibitor is exhibiting noncompetitive inhibition, as the inhibitor is affecting the Vmax but not the Km. To calculate the Km apparent and Vmax apparent at 3.0mM inhibitor, you can use the Lineweaver-Burk plot to extrapolate the values. The Km apparent can be calculated as the x-intercept of the extrapolated line, and the Vmax apparent can be calculated as the y-intercept of the line where 3.0mM inhibitor was used. However, it is important to note that these values may not be entirely accurate, as extrapolating from the data may introduce some error. It would be best to validate these values through further experimentation or by using a more accurate method such as nonlinear regression analysis.