Catalysis-12 Flashcards
WHat do enzymes do
lower activation energy
stabilize transition state
What do enzymes NOT do
change delta G (free energy difference between energy of the reactants and the products) of the reaction
Irreversibly change shape
Which constant is used when the reaction is NOT at equilibrium?
Which constant is used when the reaction is at equilibrium
Q
K
What is the formula of delta G when the reaction is NOT at equilibrium
deltaG= delta G prime + RTlnQ
What are the two biochemical strategies used to drive an unfavorable reaction
create a pathway to use up the products and shift the reaction toward equilibrium
couple the reaction to a more energetically favorable reaction
Define the following thermodynamics terms
transition state
activation energy
transition state- the highest energy point in the reaction and is the most unstable
activation energry: energy barrier that must be overcome for the reaction to proceed
explain the induced fit model
when substrate binds to enzyme and the enzyme changes shape so the substrate binds more tightly and is forced into the transition state
What occurs in covalent catalysis
electron transfer
What occurs in acid- base catalysis
proton transfer to substate
Why is approximation important to enzyme catalysis
enzymes bring substates together which decreases the entropy which will lead to lowering the delta G of the reaction
What occurs in electrostatic catalysis
unfavorbale charges are stabilized by polarizable side chains in the enzyme and or metal ions
What catalytic strategies occur in chymotrypsin reaction
covalent catalysis
acid- base catalysis
What catalytic strategies occur in carbonic anhydrase reaction
acid base catalysis
approximation
electrostatic catalysis
What amino acids make up the catalytic triad found in chymotrypsin
serine,
histidine
aspartic acid
in the Chymotryspin enzyme mechanism what is the oxyanion hole? what composes it?
Step in the chymotrypsin mechanism that stabilizes the tetrahedral intermediate and containes serine and glycine
