Question

Is determining the modality (competitive, uncompetitive, noncompetitive) of an inhibitory compound important? If so, why? Under what conditions ([S] vs. KM) is a competitive inhibitor the most effective? Under what conditions is an uncompetitive inhibitor the most effective?

Answer 1

Modality means a mode in which something exists, in case of enzymes inhibitors this can be understood as a mode when they work efficiently. Inhibitors are very important not only in industries but even in pharmaceutical. So, it is important to understand their modality to utilize them in more efficient way.

In [S vs Km], competitive inhibitors are tend to increase Km as they bind to free enzyme substrate rather ES( enzyme- substrate)complex which leds to fixed Vmax. Increase in free enzyme and decrease in substrate give ample opportunity for inhibitors to halt catalysis but if ES is much in number then inhibitors cant stop catalysis.

In uncompetitive inhibition, inhibitors become more active with increase of substrate concentration as it leads to increase in ES complex. Hence more place for inhibitors to act on and more effectively catalysis they can halt.

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