BIO 435 BIO 435
ENZYMOLOGY ENZYMOLOGY
IV. WEEK
ENZYMATIC CATALYST
MECHANISMS
E + S ES EP E + P
SPECIFICITY is the Key to Enzyme
Action
ENZYM-SUBSTRAT ENZYM-SUBSTRAT
INTERACTION INTERACTION
There are two enzyme–substrate models:
1. Lock-and-key model 2. induced-fit model
1. 1. Lock-and-key modelLock-and-key model
The substrate fits in the active site much like a key fits in a lock.
II. induced-fit model
the active site is flexible and undergoes a conformational change
Weak interactions between the enzyme and substrate
are the most effective in the transition situation…
The weak between enzyme and substrate
interactions are important for enzymatic catalysis
routing power...
Non covalent (weak) bonds Non covalent (weak) bonds
Hydrogen bonds
Electrostatic bonds Van der Waals
interactions
