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 mevalonate pathway is ) xz)3el , i,s/awbdft shown below. Inhibitors to the enzyme HMG- CoA reduc 7od8rlcq; fjq hp5 +f6tase can lower the producti f5 6qd7fhp lr;jq+o8con of cholesterol.
Statins lower cholesterol, reduce the risk of heart attacks, and prevent strokes. They are known to inhibit HMG-CoA reductase, which is the rate-limiting enzyme of cholesterol biosynthesis in the mevalonate pathway (image above).
Which of the following describes the mechanism of action of statins in lowering cholesterol?
A. Statins are competitive inhibitors of HMG-CoA reductase, the rate-limiting enzyme of cholesterol biosynthesis.
B. Statins bind to an allosteric site on HMG – CoA reductase, an enzyme in the pathway to cholesterol biosynthesis.
C. Statins bind to the enzyme-substrate complex of HMG- CoA reductase and thereby inhibit enzyme activity.
D. Statins are irreversible inhibitors of the enzyme HMG- CoA reductase.
参考答案: A
本题详细解析:
Statins are competitive inhibitors of the substrate for HMG-CoA reductasz -6:3qfpzgrm6 witq 0j:t3yee and bind at the active site of the enzyme (Choice A).
Statins do not bind at an allosteric site of the enzyme HMG-CoA reductase (Choice B), so they are not non-competitive inhibitors.
Statins do not inhibit by binding to the enzyme-substrate complex to inhibit activity (Choice C).
Statins are com y3q ifrpt06: zjt6emg-q:wz 3petitive inhibitors, so inhibition is reversible in the presence of increasing substrate concentrations (Choice D).
| 
