Now use the data and determine the V_max and K_Mfor plot A:
V_max =                    K_M=                   
Calculate this by substituting one set of data into the Michaelis-Menton equation and solving for either V_max or K_M.

     Repeat the same calculations for plot B: V_max =                      K_M=              

     What calculation do you need to make for plot C?                     What is the result?                                                                  

2. The chart in exercise 1 was made in Excel using this formula for calculating v₀ :
  = (a2*V_max )/(a2+K_M)   where a2 was the first cell with a value for [S] and numbers were assigned for V_max and K_M. If you have access to Excel, prepare to make a similar chart by entering a column of values for [S] ranging from 0 to 1000 mM, increasing by 50 mM for each line. (If you're lazy, you can do this by making the second cell = the first cell + 50 and then copying and pasting.)
a. Calculate v₀ with V_max = 800 and K_M= 100.
b. Calculate v₀ with V_max = 600 and K_M= 100. If you do this by copying the formula from
     the second column, make sure this still uses a2, not b2.
c. Calculate v₀ with V_max = 1,000 and K_M= 200.
Make a scatter plot with lines using all three sets of data. Show major gridlines for the x axis and adjust the x axis scale to a maximum of 1,000 (800 also works well).

3. Evaluate the curves generated in question 2 by answering the questions.
a. Can you identify the V_max for each curve?
b. Can you tell that the V_max for each curve is different?
c. Given the V_max for each curve, would you be able to identify the K_M?

4. Now return to column a ([S]) and add [S] up to 10,000 in increments of 1,000. Copy and paste the formulas for v₀ so that you have the additional values, and prepare a chart for all three curves that includes these values. Adjust the x axis scale to maximum of 10,000.
Answer a-c from question 3 for the revised chart.
d. From what you have been told about enzyme behavior in the cell, is it more important
     to know the V_max or the K_Mto be able to compare two different enzymes?

5. If time permits, repeat question 2 with these values:
a. Calculate v₀ with V_max = 800 and K_M= 100.
b. Calculate v₀ with V_max = 800 and K_M= 200.
c. Calculate v₀ with V_max = 800 and K_M= 300.
Make a scatter plot with lines using all three sets of data as before. This is your Michaelis-Menton chart to show competitive inhibition.

     Convert the data to Lineweaver-Burk data by following these steps:
a. Prepare a column = 1/[S] in column f. Do not use [S] = 0, but start with
     1/[S] = 1/50 in cell f3.
b. Prepare a column of 1/v₀ for Lineweaver-Burk by entering this formula:
     = (100/800)*f3+1/800.
c. Repeat this for the other two plots. The formulas will be =(200/800)*f3+1/800 and
    =(3/8)*f3+1/800.

     Plot the data. In order to see the y-intercepts, you will have to add a linear trendline for each plot, and in order to see the x-intercepts each trendline must extend backward by 0.010 (check options for each trendline). I've found it difficult to see the y-axis without changing its weight, and I also find it helpful to adjust the scales on both axes.

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