enzymes€¦ · 4) enzymes lower activation energy & speed up reactions by: • acting as...
TRANSCRIPT
Enzymes
Learning Goals• Understand how enzymes do and how they
function
• Understand factors affecting enzyme activity
What is an Enzyme?•
Lock and Key Model• Enzymes are specific to their substrate(s)
Enzyme-Substrate Complex• Substrates bind to an active site
Forms an
• Active site undergoes a
to better accommodate the substrate
Why Enzymes?• Heat usually speeds up reactions.
•
Enzyme Energy Profile
Enzyme Energy Profile
An
abo
lic
Rea
ctio
ns 1) Substrate binds to active site
2) Enzyme changes shape to
“embrace” substrate (Induced Fit)3) Substrates held in active
site by weak interactions:
- H-bonds
- Ionic bonds
4) Enzymes lower
activation energy &
speed up reactions by:
• acting as template for
substrate orientation
• Stressing substrate &
stabilizing transition
state
• Providing favorable
microenvironment
• Participating in
catalytic reaction
5) Substrates converted into products6) Products are
released
7) Active
site
available
again
Cat
abo
lic
Rea
ctio
ns
ATP ADP + Pi
ENZYME(ATPase)
Factors that Affect Enzyme Activity
Factors that Affect Enzyme Activity
Enzyme Cofactors• Activate enzyme/protein
• Coenzyme -
Allosteric Regulation
Competitive Inhibitors
Fee
db
ack
In
hib
itio
n
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