What type of proteins do drugs target?
Enzymes, Receptors, Ion channels, Structural proteins
Each type serves a specific function in drug interactions.
What is the role of enzymes in drug interactions?
Enzymes bind tightly to the transition state (TS) and accelerate reactions by lowering the energy barrier
This does not change the reactants (R) or products (P) of the reaction.
What is the ES complex?
The complex formed by the binding of an enzyme (E) and a substrate (S)
This complex is reversible and in equilibrium.
What happens to the shape of an enzyme during substrate binding?
The enzyme changes shape to better fit the substrate
This is part of the induced fit model of enzyme activity.
What is the Michaelis-Menten kinetics?
It describes the rate of enzymatic reactions with initial substrate concentration (S)
It includes parameters such as Vmax and Km.
Define Vmax in enzymatic reactions.
The maximum velocity at which an enzyme can convert substrate to product
It occurs when all active sites of the enzyme are saturated.
What does Km represent?
The substrate concentration at which the reaction rate is half of Vmax
It indicates the affinity of the enzyme for its substrate.
What is Kcat?
The turnover rate of an enzyme, indicating how efficiently an ES complex produces product
Larger Kcat values indicate faster reaction rates.
What is competitive inhibition?
Inhibition where the inhibitor competes with substrate for the active site
Vmax remains unchanged; Km increases.
What occurs during non-competitive inhibition?
Inhibitor binds to the enzyme but not at the active site, reducing the number of active enzymes
Vmax decreases, Km remains the same.
What defines uncompetitive inhibition?
Inhibitor binds only to the ES complex, preventing the reaction from proceeding
Vmax decreases, Km decreases.
What characterizes irreversible inhibition?
Inhibitor forms a permanent bond with the enzyme, preventing its function
Example: Penicillin binds to and inhibits transpeptidase.
What is the role of messengers in cellular signaling?
They induce shape changes in receptors upon binding, transmitting signals
This can also create or destroy catalytic functions.
What is an agonist?
A substance that binds to a receptor and activates it, mimicking the effect of a natural messenger
Example: Adrenaline as an agonist for bronchodilation.
Define antagonist in pharmacology.
A substance that blocks the normal function of a receptor
Example: Tagamet blocks histamine receptors to reduce acid production.
What is a partial agonist?
A substance that activates a receptor but produces a weaker response than a full agonist
Example: Buprenorphine, which provides milder opioid effects.
What is an inverse agonist?
A substance that binds to a receptor and decreases its baseline activity
This contrasts with regular antagonists that only block receptor activity.
