Digital ACT Science Practice Question #838

Researchers investigated the catalytic reaction velocity (v) of an enzyme under varying substrate concentrations ([S]) and in the presence of two chemical inhibitors (Inhibitor X and Inhibitor Y). All assays were conducted at pH 7.4 and 37°C. Table 1: Reaction Velocity (µmol/min) vs. Substrate Concentration +-------------------+-------------------+-------------------+-------------------+ | [S] (mM) | No Inhibitor (v) | + Inhibitor X (v) | + Inhibitor Y (v) | +-------------------+-------------------+-------------------+-------------------+ | 1.0 | 15.2 | 6.1 | 4.8 | | 2.5 | 28.4 | 14.2 | 9.1 | | 5.0 | 42.1 | 27.8 | 13.5 | | 10.0 | 56.7 | 45.2 | 18.2 | | 25.0 | 68.3 | 66.9 | 22.0 | | 50.0 | 71.0 | 70.8 | 22.8 | +-------------------+-------------------+-------------------+-------------------+ Note: Competitive inhibitors bind to the active site and can be overcome by high substrate concentrations (achieving near-normal Vmax). Noncompetitive inhibitors bind to an allosteric site and reduce Vmax regardless of substrate concentration. Based on Table 1 and the provided information, which classification correctly identifies the mechanism of Inhibitor X and Inhibitor Y?