推 sa36599809:這題我也覺得很怪 08/04 12:25
→ fangtu:我也寫B的樣子 08/04 12:48
推 cestlavie523:我也寫B~~ 08/04 12:53
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推 lewdster0128:推~ 08/04 14:21
※ 引述《timothy70417 (絕地武士)》之銘言：
27 下列調控酵素活性的方式，何者為不可逆的（irreversible）？
A 異位調節（allosteric regulation）
B 共價修飾（covalent modification）
C 酶原（zymogen）的蛋白水解切割（proteolytic clevage）
D 非競爭型抑制劑（uncompetitive inhibitor）的結合
答案C
線上的stryer也寫到: fructose 1,6-bisphosphatase 是一個allosteric enzyme
他也會造成irreversible的例子
所以建議答案應該是 A或B或C
不知道這樣可以嗎?
16.3.4. The Conversion of Fructose 1,6-bisphosphate into Fructose 6-phosphate
and Orthophosphate Is an Irreversible Step
On formation, phosphoenolpyruvate is metabolized by the enzymes of glycolysis
but in the reverse direction. These reactions are near equilibrium under
intracellular conditions; so, when conditions favor gluconeogenesis, the
reverse reactions will take place until the next irreversible step is
reached. This step is the hydrolysis of fructose 1,6-bisphosphate to fructose
6-phosphate and Pi.
The enzyme responsible for this step is fructose 1,6-bisphosphatase. Like its
glycolytic counterpart, it is an allosteric enzyme that participates in the
regulation of gluconeogenesis. We will return to its regulatory properties
later in the chapter.
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