Type 4: final discrimination

Your results confirmed that, for increasing modifier concentration:

  • kcat decreases as hyperbola
  • 1/kcat increases as hyperbola
  • Km decreases as hyperbola

For the final discrimination we exploit the dependence of kcat/Km on [X]. Choose one of the following three possibilities.

<em>k</em><sub>cat</sub>/<em>K</em><sub>m</sub> is independent of modifier concentration

The sought mechanism is:

Hyperbolic catalytic inhibition, HCaI

Examples of HCaI

<em>k</em><sub>cat</sub>/<em>K</em><sub>m</sub> decreases as hyperbola

The sought mechanism is:

Hyperbolic mixed, predominantly catalytic inhibition, HMx(Sp<Ca)I

Examples of HMx(Sp<Ca)I

<em>k</em><sub>cat</sub>/<em>K</em><sub>m</sub> increases as hyperbola

The sought mechanism is:

Hyperbolic mixed, dual modification (activation → inhibition)

Examples of HMxD(A/I)

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