Card Set Information
What is a catalyst?
A substance that lowers Ea by forming a temporary association with a reacant (so it can be reused)
What do enzymes do?
Enable cellular reactions to happen at reasonable/rapid rates (critical for life)
What is an enzyme?
A globular protein that functions as a biological catalyst
Enzymes lower Ea by...
1) Orienting the substrate to facilitate the rxn, 2) Physically stretching chemical bonds, 3) Chemically altering the substrate by adding chemical groups
What is a substrate?
Molecule (reactant) enzyme acts on
Where does the substrate fit on the enzyme?
Active site (very specific, usually just a few, close amino acids)
What is induced fit?
When a substrate binds to the active site, confirmation (shape) of the protein changes (substrate gripped tighter, essential to protein function)
What is the lock and key model?
Comparison of active site-subsrate to lock-key (Emil Fisher)
What was correct and incorrect about the lock and key model?
Correct- very specific, Incorrect- enzyme and active site=much more flexible (induced fit, enzyme confirmation change)
What is a cofactor?
Non protein molecule that helps the enzyme function efficiently (can help open/stabalize active site)
What are the 2 types of cofactors?
Ions as cofactors and coenzymes
How does temp. affect enzymes?
Rxn rates increase with temp. until enzyme denatures. Then rxn rate drops. (somewhat organism dependent)
How does pH affect enzymes?
Tertiary structure depends on attractions and interactions which are affected by H+ concentration (no general rule because dependent on enzyme/environment)