Environmental Impacts on Enzyme Function Practice Test

A membrane-associated enzyme is assayed in solutions containing different detergent concentrations while keeping pH, temperature, and substrate constant. With 0% detergent, activity is 18 units; with 1% detergent, activity is 3 units. Detergents can insert into hydrophobic regions of proteins and disrupt hydrophobic interactions that help maintain tertiary structure and the shape of the active site. The enzyme amount added is the same in both trials. Which outcome is most likely at 1% detergent?

Trypsin activity is tested at 37°C in two buffered solutions containing equal enzyme and substrate concentrations. In buffer at pH 8.0, 70% of substrate is digested in 5 minutes; in buffer at pH 3.0, only 5% is digested. The enzyme is not degraded and is transferred directly between buffers. Which outcome is most likely when trypsin is returned from pH 3.0 to pH 8.0? Changes in pH can alter amino acid side-chain charges that stabilize tertiary structure and the active site.