What is the function of glyceraldehyde 3-phosphate dehydrogenase?

Question

BlackTom AI · Accepted Answer

Let’s examine what glyceraldehyde 3-phosphate dehydrogenase (GAPDH) actually does in metabolism. 
Option 1: 'oxidation of an aldehyde by NAD+ and formation of acyl-phosphate' correctly describes GAPDH activity. It oxidizes the aldehyde group of glyceraldehyde-3-phosphate and transfers the electrons to NAD+, forming NADH, while the inorganic phosphate is added to create the high-energy acyl-phosphate (1,3-bisphosphoglycerate). This is the canonical reaction in glycolysis and links the oxidation step to energy capture. 
Option 2: 'oxidation of an alcohol to an aldehyde by NAD+' is not correct here, because GAPDH acts on an aldehyde, not on an alcohol, and it oxidizes to a carboxylic acid derivative (as part of forming a phosphate acyl intermediate), not simply converting an alcohol to an aldehyde. 
Option 3: 'dehydration and dephosphorylation of GAP' describes a removal of water and phosphate, which GAPDH does not perform; dehydration/dephosphorylation would be characteristic of other enzyme activities (e.g., certain kinases or lyases) but not GAPDH’s function in glycolysis. 
Option 4: 'hydrolysis of GAP' would mean breaking GAP apart with water, which GAPDH does not do; hydrolysis would yield separate fragments rather than forming the high-energy acyl-phosphate intermediate. 
Option 5: 'removal of the 3-phosphoryl-group from GAP' would descriptively indicate dephosphorylation of GAP itself, but GAPDH does not remove the 3-phosphate from GAP; instead, NAD+-dependent oxidation occurs with phosphate incorporation into the product as part of 1,3-bisphosphoglycerate formation. 
In summary, option 1 accurately captures the dual redox and phosphoryl-transfer nature of GAPDH’s role, while the other options misstate the substrate, reaction type, or products involved.

What is the function of glyceraldehyde 3-phosphate dehydrogenase?

查看解析

登录即可查看完整答案

类似问题

Which enzyme of the ones shown below generates the first intermediate compound with a high phosphoryl‑transfer potential that is not ATP

What reaction is catalyzed by aldolase?

What two 3-carbon molecules are generated by the cleavage of fructose-1,6-bisphosphate?

Which of the following must be regenerated for glycolysis to proceed?

Which of the following is not an intermediate in the glycolytic pathway by which glucose is oxidized to pyruvate

Which of the following glycolytic reactions constitutes a major thermodynamic driving force for glycolysis in vivo

Which of the following best describes the net organic products formed during the oxidation of one molecule of glucose to two molecules of pyruvate via glycolysis

If glucose is labeled with 14C at the C1 position only, which of the following would occur if the glucose underwent glycolysis? Hint: Open chain form of Glucose has an aldehyde group at C1

更多留学生实用工具

考试浏览器助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单