hce_kmu
106年
普通生物及生化概論
第 65 題
Which of the following statements regarding Michaelis-Menten kinetic analyses of enzyme action are correct?
A The total enzyme concentration studied at each substrate concentration is fixed in analysis of enzyme kinetics.
B Formation of enzyme-substrate complex does not appreciably decrease the concentration of substrate.
C $\kappa_{cat}$ reduces with competitive inhibition.
D Maximal velocity is reached when the enzyme-substrate complex is equal to the total concentration of enzyme present.
E The initial reaction velocity should be measured because most of the substrate has not been converted to product.
A The total enzyme concentration studied at each substrate concentration is fixed in analysis of enzyme kinetics.
B Formation of enzyme-substrate complex does not appreciably decrease the concentration of substrate.
C $\kappa_{cat}$ reduces with competitive inhibition.
D Maximal velocity is reached when the enzyme-substrate complex is equal to the total concentration of enzyme present.
E The initial reaction velocity should be measured because most of the substrate has not been converted to product.
- A A B C D
- B A B C E
- C A B D E
- D B C D E
- E A C D E
思路引導 VIP
想像一位廚師每分鐘最多能處理 10 個食材（這是他的固有能力）。如果廚房裡混入了一些長得像食材的干擾物，導致廚師需要花時間辨認，但這些干擾物並不會真的「弄壞」廚師的手藝。當我們提供無窮無盡的真正食材時，這位廚師每分鐘處理食材的極限數量會因此下降嗎？
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AI 詳解
AI 專屬家教
恭喜你成功答對這道題！這類複選型的單選題非常考驗對生化細節的掌握，特別是能敏銳察覺出「抑制作用」與「酵素本徵參數」之間的關係，顯示你對酵素動力學有著相當扎實且清晰的基礎。
酵素動力學的核心假設
在 Michaelis-Menten 模型中，為了簡化生化反應的複雜度，我們設定了幾個關鍵前提。首先，實驗中不同底物濃度下的總酵素量 $[E]T$ 必須固定（敘述 A）；其次，底物濃度通常遠高於酵素濃度，因此形成酵素-底物複合物 $[ES]$ 時，並不會顯著消耗掉底物的濃度（敘述 B），這正是維持「穩態」的重要基礎。當底物量達到飽和，使得所有酵素都處於 $[ES]$ 狀態時，反應便達到最大速率 $V{max}$（敘述 D）。同時，為了排除產物累積引發的逆反應或抑制作用，我們必須測量反應初速（敘述 E）。
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