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?

View Explanation

Log in for full answers

Similar Questions

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

More Practical Tools for Students Powered by AI Study Helper

Homework AI Solver

Stylized AI Paper Writer

Plagiarism Checker Assistant

Citation AI Academic Writing Tool

In-Class Translation Assistant

AI Note Generator

AI Quiz Answers

Past Exam Questions from University Test Bank

Smart Practice Assistant

Adaptive Practice

Making Your Study Simpler