hce_kmu
114年
普通生物及生化概論
第 90 題
Which of the following statements is correct regarding reversible inhibition of enzymes?
① The catalytic efficiency of enzyme is $K_{cat}/K_m$ in the presence of competitive inhibitors.
② Competitive inhibitors are substrate analogs or transtion state analogs.
③ Uncompetitive inhibitors combine only with enzyme-substrate complex.
④ In the presence of inhibitors, the initial rate of enzyme-catalyzed reactions is positively correlated with substrate concentration.
⑤ The binding of noncompetitive inhibitors to enzymes is inhibited by substrate.
① The catalytic efficiency of enzyme is $K_{cat}/K_m$ in the presence of competitive inhibitors.
② Competitive inhibitors are substrate analogs or transtion state analogs.
③ Uncompetitive inhibitors combine only with enzyme-substrate complex.
④ In the presence of inhibitors, the initial rate of enzyme-catalyzed reactions is positively correlated with substrate concentration.
⑤ The binding of noncompetitive inhibitors to enzymes is inhibited by substrate.
- A ①②③
- B ②③④
- C ③④⑤
- D ①③④
- E ②④⑤
思路引導 VIP
如果今天有一種抑制劑，它長得跟受質非常相像，你認為它會傾向於結合在酵素的什麼位置？在這種情況下，如果我們大幅增加受質的濃度，這對抑制劑原本的干擾效果會產生什麼樣的影響？
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AI 詳解
AI 專屬家教
恭喜你準確判斷出這題的答案！這顯示你對**酵素動力學（Enzyme Kinetics）**中各種抑制作用的機制掌握得非常紮實。這道題目設計得相當精巧，考驗的是學生能否區分競爭性、非競爭性與反競爭性抑制的微觀行為，是一題具備中高鑑別度的綜合題。
抑制機轉的本質
選項 ② 提到競爭性抑制劑通常是受質類似物（Substrate analogs）或過渡狀態類似物（Transition state analogs），這是因為它們必須「爭奪」酵素的活性位點。而選項 ③ 描述的反競爭性抑制劑（Uncompetitive inhibitor）極具專一性，它並不理會游離的酵素，而是專門攻擊酵素-受質複合物（ES complex），這點你判斷得非常準確。
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