Digital ACT Science Practice Question #1221

Two biochemists debate the mechanism of enzyme inhibition for Enzyme X in the presence of Inhibitor Y: • Scientist 1 claims that Inhibitor Y is a competitive inhibitor that binds directly to the active site, increasing the apparent Michaelis constant ($K_m$) without altering the maximum reaction velocity ($V_{max}$). • Scientist 2 claims that Inhibitor Y is a noncompetitive inhibitor that binds to an allosteric regulatory site, decreasing $V_{max}$ while leaving $K_m$ unchanged. An experiment is conducted where the substrate concentration $[S]$ is increased to saturating levels ($100\times K_m$). The observed reaction velocity reaches the exact original uninhibited $V_{max}$. Which scientist's model is supported by this result?