The Meaning of Km
- In the previous lecture, we introduced the Michaelis-Menten equation and briefly discussed the
meaning of Km, the Michaelis constant
- As shown above, it represents a ratio between the rate constants for the dissociation and
formation of the enzyme-substrate complex
- If k2 is much smaller than k-1 (as is often the case), then the Michaelis
constant is equivalent to
k-1 / k1, which is just the equilibrium constant
for the dissociation of ES to E + S
- This represents the affinity that the enzyme has for the substrate.
- However, for many enzymes, Km may be a more complex function of multiple rate constants