Enzyme Inhibition: Competitive, Non-competitive, Uncompetitive
Start with the big picture
Competitive inhibitors compete with the substrate for the enzyme’s active site, increasing apparent Km while leaving Vmax unchanged; sufficiently high substrate concentration can overcome this inhibition. Non-competitive inhibitors bind at an allosteric site on either the enzyme or enzyme–substrate complex, lowering Vmax without changing Km. Uncompetitive inhibitors bind only to the enzyme–substrate complex, lowering both Km and Vmax by the same factor. Their Lineweaver–Burk patterns also differ: competitive lines meet on the y-axis, non-competitive lines on the x-axis, and uncompetitive lines remain parallel. The lesson also connects these mechanisms to clinical examples and outlines a diagnostic approach based on changes in kinetic parameters and plot intersections.
What you'll learn
- Distinguish the binding sites and complexes involved in the three inhibition types.
- Predict how competitive, non-competitive, and uncompetitive inhibition affect Km and Vmax.
- Identify each inhibition type from its Lineweaver–Burk plot pattern.
- Relate selected clinical examples to their inhibition categories.
- Use kinetic changes to guide identification of an inhibition type.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
