Describe6 marksChallenge
A bacterial enzyme, hydrolase X, catalyses the breakdown of a pollutant substrate S. The initial rate of reaction was measured at different substrate concentrations. The results are shown in the table.
| [Substrate] / mM | Initial rate / μmol min⁻¹ |
|---|---|
| 0.1 | 0.8 |
| 0.2 | 1.5 |
| 0.5 | 3.0 |
| 1.0 | 4.5 |
| 2.0 | 5.8 |
| 5.0 | 6.5 |
| 10.0 | 6.8 |
| 20.0 | 6.9 |
Describe the effect of increasing substrate concentration on the initial rate of reaction, and explain why the rate eventually stops increasing. In your answer, explain how the maximum rate (Vmax) is used to derive the Michaelis constant (Km) and how the addition of a competitive inhibitor would alter the relationship between substrate concentration and initial rate.