Glycolysis is the process of breaking down glucose (sugar) molecules into pyruvate molecules.
Pyruvate is then used in the Krebs cycle to produce energy.
The rate limiting enzyme of glycolysis is glyceraldehyde-3-phosphate dehydrogenase (G3PDH).
G3PDH is responsible for the conversion of glyceraldehyde-3-phosphate (G3P) to 13-bisphosphoglycerate (13BPG).
13BPG is then used in the Krebs cycle to produce energy.
The rate of glycolysis is limited by the rate of G3PDH.
If the rate of G3PDH is slow the rate of glycolysis will be slow.
If the rate of G3PDH is increased the rate of glycolysis will also increase.
The activity of G3PDH is affected by a number of factors including:
-Allosteric inhibitors: These bind to the enzyme and change its shape so that it can no longer bind to its substrate. A common allosteric inhibitor of G3PDH is 3-phosphoglycerate (3PG).
-Covalent inhibitors: These bind to the enzyme and modify it chemically. A common covalent inhibitor of G3PDH is bisphosphoglycerate (BPG).
-Temperature: The activity of enzymes is usually highest at moderate temperatures.
-pH: The activity of enzymes is usually highest at neutral pH.
The activity of G3PDH can also be affected by mutations. Mutations can either increase or decrease the activity of the enzyme.
Some mutations that increase the activity of G3PDH include:
-The R458W mutation: This mutation increases the affinity of the enzyme for its substrate glyceraldehyde-3-phosphate.
-The A207T mutation: This mutation increases the activity of the enzyme by stabilizing it in its active conformation.
-The A159V mutation: This mutation increases the activity of the enzyme by increasing its stability.
Mutations that decrease the activity of G3PDH include:
-The R123H mutation: This mutation decreases the affinity of the enzyme for its substrate glyceraldehyde-3-phosphate.
-The A207S mutation: This mutation decreases the activity of the enzyme by destabilizing it in its active conformation.
-The A159T mutation: This mutation decreases the activity of the enzyme by decreasing its stability.
In summary the rate limiting enzyme of glycolysis is glyceraldehyde-3-phosphate dehydrogenase (G3PDH). The activity of G3PDH is affected by a number of factors including allosteric inhibitors covalent inhibitors temperature pH and mutations.
What is the rate limiting enzyme of glycolysis?
Phosphofructokinase is the rate limiting enzyme of glycolysis.
What is the role of Phosphofructokinase in glycolysis?
Phosphofructokinase is the enzyme that catalyzes the conversion of fructose-6-phosphate andATP to fructose 16-bisphosphate and ADP.
What is the role of Glyceraldehyde 3-phosphate dehydrogenase in glycolysis?
Glyceraldehyde 3-phosphate dehydrogenase is the enzyme that catalyzes the conversion of glyceraldehyde 3-phosphate to 13-bisphosphoglycerate.
What is the role of Phosphoglycerate kinase in glycolysis?
Phosphoglycerate kinase catalyzes the conversion of 13-bisphosphoglycerate to 3-phosphoglycerate.
What is the role of Enolase in glycolysis?
Enolase catalyzes the conversion of 2-phosphoglycerate to phosphoenolpyruvate.
What is the role of Pyruvate kinase in glycolysis?
Pyruvate kinase catalyzes the conversion of phosphoenolpyruvate to pyruvate.
What is the role of Aldolase in glycolysis?
Aldolase catalyzes the conversion of fructose 16-bisphosphate to glyceraldehyde 3-phosphate and dihydroxyacetone phosphate.
What is the role of Triose phosphate isomerase in glycolysis?
Triose phosphate isomerase catalyzes the interconversion of glyceraldehyde 3-phosphate and dihydroxyacetone phosphate.
What is the role of Glucose 6-phosphate isomerase in glycolysis?
Glucose 6-phosphate isomerase catalyzes the interconversion of glucose 6-phosphate and fructose 6-phosphate.
What is the role of Phosphoglucomutase in glycolysis?
Phosphoglucomutase catalyzes the interconversion of glucose 6-phosphate and glucose 1-phosphate.
What is the role of Hexokinase in glycolysis?
Hexokinase catalyzes the conversion of glucose to glucose 6-phosphate.
What is the role of Phosphofructokinase-1 in glycolysis?
Phosphofructokinase-1 catalyzes the conversion of fructose 6-phosphate and ATP to fructose 16-bisphosphate and ADP.
What is the role of Glucokinase in glycolysis?
Glucokinase catalyzes the conversion of glucose to glucose 6-phosphate.
What is the role of Phosphoglycerate mutase in glycolysis?
Phosphoglycerate mutase catalyzes the conversion of 3-phosphoglycerate to 2-phosphoglycerate.
What is the role of Enolase in glycolysis?
Enolase catalyzes the conversion of 2-phosphoglycerate to phosphoenolpyruvate.
