Enzymatic Mechanism of Class I Aldolase

Questions and Answers

What is the function of aldolase?

Regulates blood sugar levels

Breaks down fatty acids

Catalyzed reaction 4 of glycolysis (correct)

Synthesizes amino acids

What is the first step of the enzymatic mechanism of aldolase?

Substrate fructose-1,6-bisphosphate binds to enzyme.

What happens in step 2 of the reaction mechanism?

Epsilon amino group of Lys attacks the carbonyl of the substrate, forming protonated Schiff base with loss of H2O.

What occurs during step 3 of aldolase action?

Asp acts as a general base, leading to aldol cleavage between the 3rd and 4th carbon, forming enamine intermediate and releasing product 1, glyceraldehyde-3-phosphate. Signup and view all the answers

What is formed in step 4 after the enamine intermediate is protonated?

A new protonated Schiff base complex is formed. Signup and view all the answers

What happens in step 5 of the aldolase mechanism?

The protonated Schiff base is hydrolyzed, releasing product 2, dihydroxyacetone phosphate, and the enzyme is free to begin a new cycle of catalysis. Signup and view all the answers

Study Notes

Function of Aldolase

Catalyzes reaction 4 in glycolysis
Cleaves biphosphorylated hexose into two 2-phosphorylated trioses

Substrate Binding

Fructose-1,6-bisphosphate is the substrate that binds to the aldolase enzyme
This initiates the first step of the enzymatic mechanism

Formation of Schiff Base

The epsilon amino group of lysine attacks the carbonyl of the substrate
This leads to the formation of a protonated Schiff base and the loss of water

Aldol Cleavage

Aspartate acts as a general base, facilitating aldol cleavage
Cleavage occurs between the 3rd and 4th carbon of the substrate
Produces glyceraldehyde-3-phosphate and forms an enamine intermediate

Tautomerization Process

The enamine intermediate is protonated by aspartate
Undergoes tautomerization to create a new protonated Schiff base complex

Hydrolysis of Schiff Base

The protonated Schiff base is hydrolyzed
Results in the release of the second product, dihydroxyacetone phosphate
The enzyme is now free to begin a new catalytic cycle

Description

Explore the enzymatic mechanisms of Class I aldolase through these flashcards. Each card delves into the specific steps involved in the reaction, providing insights into substrate interaction and catalytic action. Perfect for students looking to master glycolysis and enzyme function.