Following several experiments,the data presented on the graph below was obtained.What can you determine from this graph?
A)This data may have been collected both in the absence (solid line)and presence (dashed line)of a competitive inhibitor.
B)This data may have been collected both in the absence (solid line)and presence (dashed line)of a mixed (noncompetitive)inhibitor.
C)This data may have been collected both in the absence (solid line)and presence (dashed line)of mechanism based inhibitor.
D)This data may have been collected both in the absence (solid line)and presence (dashed line)of an inhibitor which binds the active site.
E)More than one of the above are correct.

Question

Following several experiments,the data presented on the graph below was obtained.What can you determine from this graph? 
A)This data may have been collected both in the absence (solid line)and presence (dashed line)of a competitive inhibitor. 
B)This data may have been collected both in the absence (solid line)and presence (dashed line)of a mixed (noncompetitive)inhibitor. 
C)This data may have been collected both in the absence (solid line)and presence (dashed line)of mechanism based inhibitor. 
D)This data may have been collected both in the absence (solid line)and presence (dashed line)of an inhibitor which binds the active site. 
E)More than one of the above are correct.

Quizplus · Accepted Answer

The graph shows two lines, one solid and one dashed, indicating that the experiment was carried out both in the absence and presence of an inhibitor. The fact that the dashed line is shifted downwards suggests that the inhibitor is reducing enzyme activity. The shape of the inhibition curve is indicative of a noncompetitive inhibitor, as the maximum reaction rate (Vmax) is decreased and the apparent affinity for the substrate (Km) remains unchanged. Therefore, the best choice is B, which suggests that the data may have been collected in the presence of a mixed (noncompetitive) inhibitor.

Following Several Experiments,the Data Presented on the Graph Below Was