Enzyme Kinetics Flashcards
Enzymes speed up reactions by
Lowering the AE of the reaction
What is the equation of rate?
Rate = k[reactants]
How can you increase the rate of a reaction?
- Increase substrate concentration
- Increase enzyme concentration
Vmax lets us know that
At really high concentrations of substrate, enzyme will be saturated and full of substrate
At Vmax, the enzyme will not be able to
React any more quickly
Protein synthesis or degradation does not change
Enzyme concentration
Environmental factors like changes in temperature do not influence
The rate constant K
The Steady-State Assumption is
At a concentration where enzyme-substrate complex is constant
What is the Michaelis-Menten Equation?
Vo = (Vmax [S]) / (Km + [S])
Km is the
Michaelis Constant
Km is the concentration of
Substrate at which reaction speed is 1/2Vmax
The lower the Km is the
Better our enzyme works
The Michaelis Constant can be used to
Quantify enzyme’s ability to catalyze reactions (called Catalytic Efficiency)
What is the equation for Catalytic Efficiency?
Kcat / Km
A covalent catalysis involves the
Sharing of electrons between two molecules
Proximity or orientation catalysis involves the
Rearrangement of molecular bonds by the basic collision of two molecules together
Keto-enol tautomerization is what kind of catalysis?
Acid/Base catalysis
What happens during competitive inhibition?
- Km changes
- Vmax stays constant
What happens during uncompetitive inhibition?
- Km decreases
- Vmax decreases
What happens during noncompetitive inhibition?
- Km stays constant
- Vmax decreases
Enzymes increase the rate of a reaction by
Stabilizing the transition state
What is Allosteric Inhibition?
The binding of a ligand to a protein outside of the active site
Uncompetitive inhibition involves the binding of an
Inhibitor to both the free enzyme and enzyme-substrate complex
What happens in feedback inhibition?
The product of a reaction inhibits the enzyme that helped produce it
A low Km indicates
Higher affinity for substrate
Which enzyme would be more easily saturated?
One with a lower Km
Compared to substrates, enzymes bind more tightly to
Transition states
Before induced fit occurs, the order of a reaction must undergo
The initial binding
What is a cofactor?
A non-protein chemical compound bound to an enzyme to assist in catalysis
What is a coenzyme?
A specific type of cofactor that carries chemical groups between enzymes
What is a holoenzyme?
The complex of an enzyme that has its cofactor bound and is considered ‘complete’
What has the effect of increasing the Vmax of a reaction upon binding to an enzyme?
An activator
