BIO 435 BIO 435
ENZYMOLOGY ENZYMOLOGY
IX. WEEK
ENZYME
INHIBITION
•
Inhibitors
– molecules that reduce enzyme
activity
1. 1. Reversible inhibition Reversible inhibition occurs when the inhibitor occurs when the inhibitor
causes a
causes a temporary temporary loss of activity.
loss of activity.
Reversible inhibitors can be Reversible inhibitors can be
competitive or
competitive or
noncompetitive
noncompetitive
Competitive inhibitor
Inhibitor & substrate “compete” for active site
penicillin
blocks enzyme bacteria use to build cell walls
Noncompetitive inhibitor
Inhibitor binds to site other than active site
Cyanide poisoning Anti-cancer drugs
2. Irr
2. Irr eversible inhibition eversible inhibition
Inhibitor permanently binds to enzyme Inhibitor permanently binds to enzyme
competitor competitor
permanently binds to
permanently binds to active siteactive site allosteric
allosteric
nerve gas
sarin
many insecticides
