An inhibitor binds elsewhere on the enzyme, lowering Vmax without changing Km.
The inhibitor binds to a site other than the active site on either the free enzyme or the enzyme-substrate complex, changing its shape and reducing catalytic efficiency. Adding more substrate cannot fix it, so Vmax falls while Km is unchanged.
Heavy metals such as lead and mercury often act this way.
An inhibitor binds elsewhere on the enzyme, lowering Vmax without changing Km.
Noncompetitive Inhibition is one of the 51 topics in Biomolecules & Biochemistry. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Michaelis-Menten Kinetics, Induced Fit Model, Active Site.
Cyanide binds cytochrome c oxidase and blocks respiration.
Work through the Beginner topics in Biomolecules & Biochemistry first, such as Water Properties, Carbon Chemistry, Carbohydrates, then return to Noncompetitive Inhibition. Advanced topics assume the Intermediate vocabulary.
The closest topics to Noncompetitive Inhibition are Michaelis-Menten Kinetics, Induced Fit Model, Active Site, Competitive Inhibition. Comparing them side by side is a good way to see how the ideas connect.
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Noncompetitive Inhibition. To practise the whole of Biomolecules & Biochemistry, use the Biomolecules & Biochemistry quiz.
Noncompetitive Inhibition: An inhibitor binds elsewhere on the enzyme, lowering Vmax without changing Km. Michaelis-Menten Kinetics: Models reaction velocity as Vmax times substrate over Km plus substrate, describing enzyme saturation. Read both side by side and note what each one explains.
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Michaelis-Menten Kinetics and explain the difference aloud. Finally, take the Biomolecules & Biochemistry quiz and come back to this page for any question you miss.
Models reaction velocity as Vmax times substrate over Km plus substrate, describing enzyme saturation.
⚗️ Biomolecules & BiochemistrySuggests the enzyme's active site changes shape slightly as the substrate binds, improving the fit.
⚗️ Biomolecules & BiochemistryThe specific pocket on an enzyme where the substrate binds and the reaction takes place.
⚗️ Biomolecules & BiochemistryAn inhibitor resembling the substrate binds the active site and can be overcome by more substrate.
⚗️ Biomolecules & Biochemistry