Enzymes Flashcards
What is an apoenzyme?
Inactive protein component that requires coenzyme to activate
What is a holoenzyme?
Enzyme with its cofactor
What bonds are used in substrate binding at active site?
H-bonds
Electrostatic interactions
Hydrophobic interactions
Van der waal’s forces
What effects reaction velocity?
Temperature
pH
Concentration of enzyme
Substrate concentration
What is the Michaelis Menton equation?
Vi = (Vmax [S])/(Km + [S])
What is Km?
Rate constant
Km = [S] at half maximal velocity
If large, affinity is low
What is the lineweaver burke equation?
1/Vi = Km/(Vmax + [S]) + 1/Vmax
What are the three types of reversible inhibition?
Competitive
Non-competitive
Uncompetitive
What is competitive inhibition and its effects on MM?
Inhibitor binds at same site as substrate
Vmax stays the same
Km has apparent increase
What is noncompetitive inhibition and its affects on MM?
Inhibitor binds at different site than substrate, and can bind to free enzyme or ES complex
Vmax decreases
Km stays the same
What is uncompetitive inhibition and its effects on MM?
Inhibitor binds to active site of ES complex
Km decreases
Vmax decreases
What are three processes of enzyme regulation?
Allosteric enzymes
Covalent modifications
Induction or repression of enzyme synthesis
How are allosteric enzymes regulated?
Use effectors at allosteric site that alter affinity for substrate or modify Vmax
What is a homotropic effector and how do they effect enzymes?
The substrate itself
Exhibit cooperativity, binding of one substrate increases affinity for more
What is a heterotropic effector?
Different than substrate
