Enzyme Kinetics And Inhibition Flashcards
How do enzymes increase the rate of reaction?
Lower activation energy of the reaction
Give 6 key features of Enzymes
Proteins Specific No effect on equilibrium Increase rate of reaction Unchanged after reaction Cofactors may be required
Define active site
Place where substances bind and the chemical reaction occurs
Few aa’s long
Exclude water
What are the two models for enzyme substrate interaction at active site
Induced fit
Lock and key
Describe relationship between [S] and rate.
Rate increases until enzyme saturated
What effect does increased the concentration of enzyme have on maximal velocity?
Increases it
Define enzyme activity
Decrease in [s] /unit time
Increase in[p]/ unit time
Define Vmax
Maximal rate when all enzymes are saturated with substrate
Define Km
Substrate concentration that gives half the maximal velocity
What is the international uni of enzyme activity?
The amount of enzyme that converts 1 umole of substance per minute under standard conditions
How do you work out rate from graph?
Gradient at time =0 on time vs product graph
only time [S] is known
What is a Km a measure of?
Affinity of enzyme for it substrate
Low km= high affinity
High km = low affinity
What does the x intercept of a line weaver Burke plot show?
-1/Km
What does the y intercept of a lineweaver Burke plot show?
1/Vmax
What is the effect of a competitive inhibitor on Vmax and km?
Vmax remains the same
Km increases
