Described the Modes of Inhibition

Describe Competitive Inhibition

• Reversible

• Binds at Catalytic Site but NOT CATALYZED

• Looks like substrate

• Can be reversed by increasing [Substrate]

• Km Increases, Vmax stays the same

What form of Inhibition does this Graph Represent? What is Changing?

Competitive.

Km is increasing. Vmax stays the same.

Describe Noncompetitive Inhibition

• Allosteric

• Inhibitor binds to Allosteric site (not catalytic site)

• Has no effect on Substrate binding

• Prevents Catalysis by altering catalytic site

• Km stays the same, Vmax decreases

What form of Inhibition does this Graph Represent? What is Changing?

Noncompetitive.

Km stays the same, Vmax decreases

Describe Uncompetitive Inhibitors

• Doesn’t bind to enzyme until substrate binds first

• Binds to enzyme-substrate complex (pseudo binding site)

• Prevents catalysis

• Km decreases, Vmax decreases

What form of Inhibition does this Graph Represent? What is Changing?

Uncompetitive

Km and Vmax decrease

Describe Transition State inhibitors

• Inhibitor mimics the transition State of the substrate to lock enzyme in transition State (most stable)

• IRREVERSIBLE

• Binds to catalytic site and creates enzyme + inhibitor complex

• Increasing substrate doesn’t reverse inhibition

Describe Suicide Inhibition

• Binds to catalytic site and is catalyzed

• Becomes COVALENTLY BOUND

• Less potent that transition State inhibitors

• Single use

• Mimics substrate and won’t leave catalytic site

• IRREVERSIBLE

• Time dependent