Describe5 marksStandard
A student investigates the effect of substrate concentration on the rate of an enzyme-catalysed reaction. The enzyme is lactase and the substrate is lactose. The rate of product formation is measured at different lactose concentrations. The results are shown in the table.
| Lactose concentration (mM) | Rate of product formation (μmol/min) |
|---|---|
| 0.0 | 0 |
| 0.2 | 0.8 |
| 0.5 | 1.5 |
| 1.0 | 2.0 |
| 2.0 | 2.3 |
| 5.0 | 2.5 |
| 10.0 | 2.5 |
Describe why increasing the lactose concentration beyond 5.0 mM does not result in a further increase in the rate of product formation. In your answer, refer to the terms Vmax and Km.