The KM of an enzyme is always decreased by which class of inhibitor?A.MixedB.NoncompetitiveC.CompetitiveD.Uncompetitive

The KM of an enzyme is always decreased by the Uncompetitive class of inhibitor.

Here's a step-by-step explanation:

1. Enzyme inhibitors are molecules that interact in some way with the enzyme to prevent it from working in the normal manner. There are a variety of types of inhibitors including: nonspecific, irreversible, reversible - competitive and noncompetitive.

2. Competitive inhibitors are substances that compete with the substrate for the same active site on the enzyme. They do not change the KM of an enzyme.

3. Noncompetitive inhibitors are substances that bind to the enzyme at a location other than the active site. They also do not change the KM of an enzyme.

4. Mixed inhibitors can bind to the enzyme at the same time as the enzyme's substrate. However, the binding of the inhibitor affects the binding of the substrate, and vice-versa. This type of inhibition can be reduced, but not overcome by increasing concentrations of substrate. They do not decrease the KM of an enzyme.

5. Uncompetitive inhibitors, on the other hand, bind to the enzyme-substrate complex, locking them together. This type of inhibition is rare and causes a decrease in both the enzyme's maximum rate of reaction (Vmax) and the Michaelis-Menten constant KM.

So, the answer is D. Uncompetitive.