Lecture 10 - Enzyme kinetics Flashcards
In a reaction of the form A + B → P, rate of the reaction can be expressed in terms of:
- Rate of disappearance of one of the reactants
- Rate of appearance of the product
Overall order of a reaction is the sum total of
all exponents
A first order reaction describes a reaction whose rate depends on
the first power of the concentration of a single reactant
A second order reaction describes a reaction whose rate depends on
the product of the concentrations of two reactants
A zero-order reaction describes a reaction whose rate
is independent of the concentration of the reactant
In a zero-order reaction, the rate depends on the
presence of catalysts
Enzyme catalyzed reactions exhibit zero-order kinetics when
the reactant concentrations are so high that the enzyme is completely saturated with reactant molecules
k1
Rate constant for the formation of ES from the enzyme, E, and the substrate, S
k-1
Rate constant for the dissociation of the ES complex
k2
Rate constant for the conversion of the ES complex to product
In a steady state, the concentration of the ES complex
remains practically constant
A steady state requires equal rates for
ES generation and ES decomposition
For many enzymes, v0 varies with
substrate concentration
The relationship between v0 and substrate concentration is described by the
Michaelis-Menten equation
Km stands for
Michaelis constant
