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The following kinetic data was obtained using a substrate and an inhibitor. Find Km and Vmax for the substrate in mM and mM/min, then determine the type of inhibition and determine the Ki or Ki's.

[S] mM [I] mM Rate mM/min
10 0 600
20 0 667
30 0 692
40 0 706
50 0 714
60 0 720
10000 0 750
10 30 273
20 30 400
30 30 474
40 30 522
50 30 556
60 30 581
10000 30 749
10 60 176
20 60 286
30 60 360
40 60 414
50 60 455
60 60 486
10000 60 748
10 100 120
20 100 207
30 100 273
40 100 324
50 100 366
60 100 400
10000 100 746

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Solution Preview

Please open up the Excel file that I attached.

The first thing I did was to transfer the data from the Word document into Excel. No problem there.
Then, I reformatted the data so that it looked uncluttered. Essentially, remove all formatting for the cells.

Next, we want to obtain double-reciprocal data so that we can plot and analyze the data easily. This is important so that we can create a Lineweaver-Burke plot. Therefore, you will see that I created two new columns, 1/[S] and 1/rate.

Then we create a plot to visualize the data.

To do this, highlight everything from D2 to E8. Make sure you understand this. Start your highlighting in D2 and go to E8. You should have a block of 14 cells highlighted.

Once you've done that, go to Chart Wizard and select XY (Scatter) and select the subtype with no connecting line. All you want is the data points. Click "Finish."

You will see a preliminary graph for the data set with no inhibitor present.

Right click on ...

Solution Summary

The expert examines enzyme and inhibitors. The type of inhibition and Ki and Ki's are determined.

See Also This Related BrainMass Solution

Enzyme inhibitor in a reaction

Five reaction mixtures containing equal concentrations of an enzyme are prepared to the substrate concentrations indicated in the table below, and the initial rates are measured. The experiment is then repeated with an enzyme inhibitor present at a concentration of 2.2 x 10-4 M in each reaction mixture. By use of Lineweaver-Burke plots (or other plots) of these data, graphically determine KM for the substrate, KI for the inhibitor, and Vmax in the presence and absence of inhibitor. Is this a competitive or noncompetitive inhibitor?

*Note: I have included a small table with this problem as an attachment. It should be straight forward; please let me know if you have any problem opening it.

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