# Why does the Michaelis-Menten constant decrease in the presence of non-competitive inhibitor?

Non-competitive inhibitors don't bind to the active sites of enzymes. However, in the presence of non-competitive inhibitors, the Michaelis-Menten constant is found to decrease. Why is this so?

• The premise of the question is wrong. In MM kinetics, non-competitive inhibition does not change $K_M$. – Curt F. Jun 23 '17 at 19:57