Module 3: Lesson 7 Enzyme Inhibition

University:
Boston University
Course:
CAS BI 527 | Biochemistry Laboratory 1
Academic year:

2022
Views:

0

Pages:

1
Author:

asia adams lemar

**Enzyme Inhibition** **Irreversible Inhibitors (Suicide Inhibitors)** * Covalently bind to enzyme * One inhibitor molecule can permanently shut off one enzyme molecule * Often structural analogs of substrates or products * Can be used as drugs * Does not affect catalysis **Reversible Inhibitors** * Bind to and can dissociate from enzyme * No change in Vmax, apparent increase in Km **Competitive Inhibition** * Binds to active site * Often structural analogs of substrates or products * Lineweaver-Burk lines intersect y-axis * Can be overcome by increasing substrate concentration **Un-Competitive Inhibition** * Only binds to ES complex * Decreases Vmax, apparent decrease in Km * Lineweaver-Burk lines intersect x-axis **Enzyme Allosteric Regulation** Allostery: binding to a site *different* from the active site causes a change in shape of the enzyme, affecting its function. * Binding of a modulator to a regulatory site can either increase or decrease enzyme activity. * Allosteric enzymes often have multiple subunits. **Allosteric Regulation Kinetics** * **Sigmoidal Kinetics:** Cooperative binding of substrate to multiple subunits. * **T state:** Less active enzyme * **R state:** More active enzyme * **Allosteric Activator:** Binds to the regulatory site, stabilizing the R state. * **Allosteric Inhibitor:** Binds to the regulatory site, stabilizing the T state. **Examples of Allosteric Enzymes:** * Hemoglobin * Phosphofructokinase * Aspartate transcarbamoylase