Enzyme Kinetics Flashcards
What is an enzyme?
An enzyme is a biological catalyst that speeds up chemical reactions. They do not change the equilibrium constant
How is rate calculated?
Rate = Distance in meters divided by the time in seconds
Units of rate is: meters/second
Why do we need to study enzyme kinetics?
Determine the maximum rate of an enzyme
Determine the binding affinities of substrates and inhibitors
Determine the reaction mechanism
Understand the role of the enzyme in a metabolic pathway
Explain the vale for rate for product and substate
Products = positive
Substate = negative
Define rate
Rate V (velocity) is the change of concentration per unit time
Explain what the rate law and rate constant is
Rate Law (Rate Equation) : The expression which indicates how the rate of reaction depends on the concentration of the reactants and catalysts
Every chemical reaction has its own rate law because, every chemical reaction is different
Give the general equation for rate constant and rate law
Rate ∝ [Substrate]
Rate = k [Substrate]
Explain the Michaelis - Menten Kinetics model
Model that accounts for the kinetic characteristics that exists between the rate of reaction and [Substrate]
Relevant at the beginning of the reaction
E + S (reversible) Es —> E + P
Explain what the Lineweaver- Burk plot is
The Lineweaver-Burk plot can also tell us what kind of inhibition, if any, is occurring
What is an inhibitor?
Molecule which binds to an enzyme that affects the rate of an enzyme-catalysed reaction
Reversible and non-reversible inhibition
Name the main 3 types of reversible inhibition
Competitive
Uncompetitive
Non-competitive
Explain what happens in reversible inhibition
Substrate binds to active site in enzyme, this reaction is reversible
Explain what happens in competitive inhibition
An inhibitor binds to the active site of the enzyme, preventing substarte from binding
Inhibitor has no effect on V max but does increase Km
Explain what happens in uncompetitive inhibition
Inhibitor only binds to the enzyme-substrate complex
Inhibitor reduces V max and Km by equivalent amounts
Explain what happens in con-competitive inhibition
Inhibitor binds to different sites in enzyme than substrate
Inhibitor decreases V mac but has no effect on Km
