Final answer:
Uncompetitive inhibition is when an inhibitor binds only to the enzyme-substrate complex, which decreases both the Vmax and Km, indicating a lower turnover rate and increased enzyme affinity for the substrate respectively.
Step-by-step explanation:
Uncompetitive inhibition is a form of enzyme inhibition where the inhibitor binds only to the enzyme-substrate complex, not to the enzyme alone. This binding decreases both the maximal reaction rate (Vmax) and the Michaelis constant (Km). Since the inhibitor only binds to the enzyme-substrate complex, it does not compete with the substrate for enzyme binding, thus uncompetitive inhibition cannot be overcome by increasing the substrate concentration. In this scenario, the Km decreases because the enzyme has a higher affinity for the substrate when the inhibitor is bound. Nonetheless, the Vmax also decreases, signifying a reduction in the maximum rate of reaction that can be achieved regardless of the substrate concentration.
A high Km value typically indicates a weaker affinity between the enzyme and the substrate, whereas a low Km value implies a stronger affinity. Since uncompetitive inhibitors lower the Km, they imply an increase in affinity between the enzyme and substrate. Nonetheless, the binding of the inhibitor results in a lower turnover rate of the enzyme, as reflected by the lowered Vmax.