Enzymes Flashcards
What is a cofactor?
Inorganic ion that typically aids the enzyme in its ability to bind substrate
What is a holoenzyme?
Catalytically active enzyme with cofactors and coenzymes bound
Enzymes push the substrate into the ________ state in order to drive the rxn
Transition
What are the 4 activation barriers? (How are they overcome?
1-entropy of molecules in solution(organize subs reduces entropy)
2-solvation shell (weak bonds desolvate)
3-substrate conformation (weak bonds alter conformation)
4-substrate orientation (enzyme induce fit)
In the enolase rxn example, how did magnesium specifically drive the rxn?
Causes a shift in electrons allowing other factors to act on the substrate
What is velocity in a rxn?
Rate of change of substrate to product
What is the michaelis-menten constant (Km)?
Substrate concentration at which 1/2 vMax has been reached
What two types of inhibition are there?
- irreversible
- reversible
What are the 4 types of reversible inhibition?
- competetive
- uncompetitive
- mixed
- Noncompetitive
How does competitive inhibition affect the rate of rxn?
Increases the Km (rxn reaches vMax slower)
How does uncompetetive inhibition mainly affect rxn rate?
VMax is reduced
How does mixed inhibition affect the rxn rate?
Both Km and vMax are affected
What does allosteric regulation do?
Increases or decreases an enzymes efficiency by binding and changing its confirmation
Since allosteric enzymes do not follow michaelis-menten kinetics, what two types of regulation do they have?
- homotropic (1 modifier)
- heterotropic (multiple levels of modifiers)
What three things do enzymes do?
- increase reaction rate
- reduce free energy needed for rxn
- increase probability of rxn
