Enzyme Inhibition Flashcards
What do inhibitors do
Compounds that decrease enzymes activity
Powerful toxins are often what in terms inhibitors
Irreversible inhibitors (inactivactors). Permanently shut off one enzyme molecule
Drugs that slow down a specific enzyme are often what inhibitor
Reversible inhibitors that can bind to and dissociate from the enzyme.
Reversible inhibitors are often what
structural analogs of substrates or products
Reversible inhibitors can bind to what 2 things
1) to the free enzyme and prevent the binding of the substrate
2) to the enzyme substrate complex and prevent the reaction
Name 3 types of reversible inhibitors
Competitive inhibitor, uncompetitive inhibitor and noncompetitive inhibitor
what is competitive inhibition
inhibitor competes with the substrate for binding to the enzyme
Competitive inhibition binds what and doesnt affect what
Bind active site
Does not affect catalysis
Competitive inhibition
1) Vmax
2) Km
3) Lineweaver and yaxis
1) No change in Vmax
2) Increase in Km
3) lines intersect at y axis, lineweaver-burk
Uncompetitive Inhibitor binds where?
At a distinct site from the active site but only to Enzyme Substrate
Uncompetitive Inhibitor does and doesn’t affect what
Doesn’t affect substrate binding
Inhibits catalytic function, prevents product formation
Uncompetitive inhibition
1) Vmax
2) Km
3) Lineweaver Burks?
1) Decrease in Vmax
2) Decrease Km
3) Lines are parallel
Uncompetitive Inhibitor lowers the concentration of what
Functional enzyme
Uncompetitive inhibitor cannot be overcome by what
Increasing substrate concentration
What does mixed inhibition bind to
Mixed inhibitors can bind to Enzymes or Enzyme substrates at a site separate from Substrates
Mixed inhibition inhibits what 2 things?
Binding of substrates and catalysis
Mixed inhibitors
1) Vmax
2) Km
3) Lineweaver Burk
1) Decrease
2) Change Km
3) Lines intersect left from the Y axis
Noncompetitive inhibitors are mixed inhibitors but what happens in terms of Km and Lines on axis
Km has no change
Lines meet on Xaxis
Noncompetitive binding of inhibitor has no effect on binding of
substrate
In practice uncompetitive and mixed inhibition are observed only for enzymes with what
2 or more substrates
effectively removes E
Uncompetitve inhibitor - [S] required to reach one-half Vmax decreases by what?
By the factor alpha’
What type of inhibitors for drugs for AIDS?
Irreversible inhibitors and transition state analogs
