3Foszfoglicerát

3-Foszfoglicerát, or 3-phosphoglycerate (3-phosphoglyceric acid), is a three-carbon phosphorylated carboxylic acid that serves as a central metabolic intermediate in many biological pathways. In biology, the commonly encountered form is the D-enantiomer, and the molecule is highly water-soluble and negatively charged at physiological pH.

In glycolysis, 3-phosphoglycerate is formed when 1,3-bisphosphoglycerate transfers a phosphate to ADP, producing ATP and 3-phosphoglycerate, a reaction catalyzed by phosphoglycerate kinase. 3-PG is then rearranged by phosphoglycerate mutase to 2-phosphoglycerate, which is dehydrated to phosphoenolpyruvate and ultimately converted to pyruvate, with additional ATP generation along the way. Thus, 3-PG is an intermediate linking glycolysis to ATP production and downstream metabolism.

In photosynthetic organisms, 3-phosphoglycerate is the first stable product of CO2 fixation by RuBisCO in the Calvin cycle. CO2 is fixed to ribulose-1,5-bisphosphate to yield two molecules of 3-PGA per CO2; these molecules are phosphorylated by ATP and reduced by NADPH to glyceraldehyde-3-phosphate, which is used for carbohydrate synthesis and regeneration of the cycle.

Beyond glycolysis and photosynthesis, 3-PG serves as a precursor for serine biosynthesis and participates in glycerol phosphate metabolism. Its role as a bridge between energy production and biomolecule synthesis makes it a foundational metabolite in many organisms.