Enzyme Kinetics: Answer Sheet Example

Example Problem:
You are given a 4.0 mg/ml solution of an enzyme (M_r = 40,000 Da).
You determine initial velocities (v_o) at several concentrations of substrate, [A].

a) Determine K_m and V_max.

b) Calculate k_cat for the reaction.

c) Submit your calculations and a graph of 1/v_o vs. 1/[A].

What we know from the problem:

1) Concentration of the enzyme = 4.0 mg/ml.

2) Enzyme M_r = 40,000 Da

What we found in the experiment:

  0.25
  0.4
  0.7
  1.0
  2.0
  3.0
  5.0
  8.0
 12
 20

0.060
0.080
0.130
0.160
0.250
0.310
0.360
0.390
0.430
0.460

4.00
2.50
1.43
1.00
0.50
0.33
0.20
0.13
0.08
0.05

16.67
12.50
 7.69
 6.25
 4.00
 3.23
 2.78
 2.56
 2.33
 2.17

MM.xls is the Excel spreadsheet used to calculate and graph these results; it can be copied to your disk.