PGAL stands for Phospho glyceraldehyde.
This molecule is a crucial intermediate in several metabolic pathways, most notably glycolysis and the Calvin cycle (the light-independent reactions of photosynthesis). It's also commonly referred to by other names, making it important to recognize these alternatives.
Alternate Names for PGAL:
- Glyceraldehyde 3-phosphate (G3P): This is perhaps the most frequently used alternative name.
- Triose phosphate (TP): This name reflects the fact that PGAL is a three-carbon sugar (a triose) with a phosphate group attached.
- 3-phosphoglyceraldehyde: A more descriptive, but less common, name.
- GA3P: Another abbreviation for Glyceraldehyde 3-phosphate.
- GADP: Another abbreviation for Glyceraldehyde 3-phosphate.
- GAP: Another abbreviation for Glyceraldehyde 3-phosphate.
- GALP: Another abbreviation for Glyceraldehyde 3-phosphate.
Role in Glycolysis
In glycolysis, PGAL is formed from fructose-1,6-bisphosphate. Importantly, glycolysis proceeds from this point with two molecules of PGAL for every initial glucose molecule, since fructose-1,6-bisphosphate is split into two 3-carbon molecules: PGAL and dihydroxyacetone phosphate (DHAP). DHAP is then isomerized into PGAL.
Role in the Calvin Cycle
In the Calvin cycle, PGAL is a product of the reduction and phosphorylation of 1,3-bisphosphoglycerate, using NADPH and ATP generated during the light-dependent reactions. This PGAL is then used to regenerate the starting molecule of the cycle, ribulose-1,5-bisphosphate (RuBP), allowing the cycle to continue. Some PGAL is also diverted to produce glucose and other organic molecules.
