Noncompetitive Inhibition

Allosteric inhibitor binds equally to the enzyme and the ES complex

• $K_m$ unaffected
  • Binding affinity of the enzyme for the substrate is unaffected, so $K_m$ is also unaffected
• $v_{\text{max}}$ decreased
  • Less enzyme to react, so $v_{\text{max}}$ decreased

Lineweaver-Burk Plot

Mnemonic

• Noncompetitive sounds like no k ($K_m$ unchanged)
• N is horizontally asymmetric, which corresponds with how its reaction diagram is asymmetric