Table of Contents

• Part I: Using intuition to think about the shape of the graph
• 1: Stalking the wild equation
• 2: What beast are we looking for?
• 3: The outline of the beast
• 4: The middle of the beast
• 5: The whole beast
• Part II: Exploring the M-M equation
• 6: The M-M equation
• 7: Notice the %
• 8: Different values for K_m
• 9: Using (and abusing) K_m
• 10: K_m in the crosshairs
• 11: What's special about K_m?
• 12: Fun with graphs
• 13: Michaelis Menten in a nutshell.
• Part III: Exploring the Lineweaver-Burke plot
• 14: Problem: how to measure K_m and V_max
• 15: Solution: a strange transformation
• 16: Measuring V_max
• 17: Measuring K_m
• Part IV: Using it all
• 18: Virtual experiment, real enzyme
• 19: Two preservatives, new kinetics
• 20: How do these preservatives work?

Analyzing the results

Here is a table of the Michaelis-Menten parameters you calculated:

Preservative	Vmax	Km
none	0.1	1.25 mM
PHBA	0.1	2.50 mM
phenylthiourea	0.05	1.25 mM

Here are the Michaelis-Menten graphs of for each of these sets of parameters:

graph

One of these preservatives works by disabling the enzyme itself. The other preservative works by competing for the active sites on the substrate. Can you tell which is which?

If a preservative (partially) disables an enzyme, would you expect the maximum rate of the reaction to stay the same, increase, or decrease?-> imagine the enzyme chained to a heavy weight or beat up by a schoolyard bully. Clearly it won't be able to work as fast as before, so V_max should decrease.

If a preservative competes for binding sites, would you expect the maximum rate of the reaction to stay the same, increase, or decrease? -> If the amount of substrate was infinite then it wouldn't matter that there was a competitor out there, so V_max should stay the same

If a preservative (partially) disables an enzyme, would you expect to reach half of V_max with the same, less, or more of the substrate? ->

If a preservative (partially) disables an enzyme, would you expect to reach half of V_max with the same, less, or more of the substrate? ->

 

 

 

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