Enzyme Inhibition
What is Inhibition?
A process by which enzyme activity is stopped, either permanently (inactivity) or
temporarily (inhibition)
Enzyme inhibitors are substance which interfere with enzyme activity
Competitive Inhibition
Inhibitor has similar shape to substrate and competes with it
Molecule with highest concentration binds to substrate
When inhibitor concentration is greater, the inhibitor blocks the substrate
With a fixed amount of competitive inhibitor, the rate of reaction increases more slowly
as inhibitor and substrate compete for the active site
Eventually the substrate overwhelms the inhibitor and the same maximum rate is
achieved
This is a reversible reaction
Non-competitive Inhibition
Inhibitor covalently binds to a separate site called the allosteric site and doesn’t
compete with substrate
Changes the 3D, tertiary structure of the enzyme and distorts the shape of the active
site, preventing substrate from binding to it
Usually irreversible due to permanent binding of inhibitor
What is Inhibition?
A process by which enzyme activity is stopped, either permanently (inactivity) or
temporarily (inhibition)
Enzyme inhibitors are substance which interfere with enzyme activity
Competitive Inhibition
Inhibitor has similar shape to substrate and competes with it
Molecule with highest concentration binds to substrate
When inhibitor concentration is greater, the inhibitor blocks the substrate
With a fixed amount of competitive inhibitor, the rate of reaction increases more slowly
as inhibitor and substrate compete for the active site
Eventually the substrate overwhelms the inhibitor and the same maximum rate is
achieved
This is a reversible reaction
Non-competitive Inhibition
Inhibitor covalently binds to a separate site called the allosteric site and doesn’t
compete with substrate
Changes the 3D, tertiary structure of the enzyme and distorts the shape of the active
site, preventing substrate from binding to it
Usually irreversible due to permanent binding of inhibitor
