Chapter 3: Enzymes
no inhibitor inhibitor A inhibitor B
v
v = velocity (rate) [S] = substrate concentration
[S]
Copy the graphs. a Label the graph for ‘no inhibitor’ to show the position of Vmax, ½Vmax and Km. b State the effect that inhibitor A had on Vmax and Km of the enzyme. c State the effect that inhibitor B had on Vmax and Km of the enzyme. d Which inhibitor is competitive and which is non-competitive? Explain your answer.
[3] [2] [2] [4]
Double-reciprocal plots of the data obtained produced the following graphs.
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X
1 v
Y Z
0
1 [S]
e Identify which line, X, Y or Z, corresponds to each of the following experiments: i inhibitor absent ii competitive inhibitor present iii non-competitive inhibitor present Briefly explain your answers to ii and iii.
[5] [Total: 16]