4. Enzyme Specificity
• Lock and Key model
• Induced fit model
– “polyaffinity mechanism”- three point attachment
5. Catalyst
Catalyst- speeds up
reaction without being
consumed (no effect on
equilibrium)
do so by lowering the
activation energy of the
rxn
activation energy- the
amount of energy
required to reach the
transition state
6. Catalyst
Catalyst- speeds up
reaction without being
consumed
do so by lowering the
activation energy of the
rxn
activation energy- the
amount of energy
required to reach the
transition state
11. Cofactors and Coenzymes
Cofactor- depends on context
– either inorganic atom
– or inorganic molecule or coenzyme
Coenzyme- organic molecule required by an
enzyme for it’s catalytic activity, usually
vitamin or vitamin derivative
34. Enzyme Active Sites
Active site- that region of the enzyme where
substrate binds and is converted to product
why the enzyme has to be bigger than substrate
35. Ways in Which an Enzyme
Performs Catalysis
Increase the effective concentration
Stabilize transition state
Put a strain on susceptible bonds
Hold reactants near each other and in the proper
orientation
Form covalent bonds with substrate that result in
destabilization of substrate
Act as proton donors and acceptors
Nucleophilic/Electrophilic attacks
36. Amino Acids of the Active Site
get good example of each
X-ray crystallography
mutagenesis
amino acid modifying reagents
37. Enzyme Regulation
On vs. off
1. Isoenzymes
2. Covalent Modification
3. Allosterism
4. Repression
5. Proenzymes
42. Proenzymes
AKA zymogens
alters the concentration of active enzyme
particularly common with:
digestive enzymes
peptide hormones
clotting factors
proteolysis is selective
dibasic example
