How do uncompetitive inhibitors affect the apparent Km and Vmax of an enzyme, and why?

• A. They increase both Km and Vmax because they stabilize the enzyme-substrate complex.
• B. They increase Km and decrease Vmax because they compete with the substrate.
• C. They have no effect on Km and Vmax because they do not bind to the enzyme.
• D. They decrease both Km and Vmax because they bind to the enzyme-substrate complex, reducing its concentration.

Answer: (D)