Explain5 marksChallenge
A researcher investigates the effect of an inhibitor X on the enzyme 'Formase', which catalyses the conversion of formate to carbon dioxide. The initial rate of reaction was measured at various substrate concentrations in the presence and absence of inhibitor X, with all other conditions (optimal pH 7.4 using phosphate buffer, 37°C) kept constant. The results are shown in the table:
| [Substrate] / mM | Rate without inhibitor (arbitrary units) | Rate with inhibitor X (arbitrary units) |
|---|---|---|
| 0.5 | 10 | 5 |
| 1.0 | 16 | 9 |
| 2.0 | 22 | 14 |
| 5.0 | 27 | 21 |
| 10.0 | 30 | 29 |
Explain whether inhibitor X is a competitive or non-competitive inhibitor. Use the data to support your answer, and explain how the values of Vmax and Km change in the presence of the inhibitor.