本题目来源于试卷: Interaction & Interdependence C.1 Enzymes & Metabolism，类别为 IB生物学
[单选题]
The graph below shows the rate of reaction of a j-cxgxyfd6cv4 a .5 kr7h7(gqlmh 15an en *gf o1m9vv2zsn5 )jhjzyme with increasing substrate concentration. Similar concentrations of chemicals A, B, C and D were added independently to the react mv2g*znh 9 o f5s1jvj)ion, and the activity was monitored for each of the reactions. The curve marked A coincides with the activity of the enzyme with no inhibitor added.
Which of the chemicals is likely to be a non-competitive inhibitor?
A.
B.
C.
D.
参考答案: C
本题详细解析:
A non-competitive inhibitor does nop t 8edxzfxyp5e f,---t compete with the substrate for the binding site, it slows down reactions by binding to the allosteric site.
Increasing the concentration of the substrate does not prevent the binding of the inhibitor, so the same proportion of inhibition is maintained at all concentrations of substrate as seen in curve C. This shows that inhibitor C is binding at a different site than the substrate and therefore is a non-competitive inhibitor. Choice C is correct.
Curve A gives the same results as those obtained when there is no inhibitor present in the reaction. Choice A is incorrect. It is likely that inhibitor A does not bind to the enzyme under investigation.
Curve B is the result 8-zff -pxye5td ,xe- pof the presence of a competitive inhibitor. Increases in substrate concentration increase the rate of reaction since the substrate and inhibitor (chemical B) bind to the same site on the enzyme. Choice B is incorrect.
Curve D increases the rate of reaction as compared to A (with no inhibitor present) and could be an activator for the reaction but not an inhibitor. Choice D is incorrect.
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