Phosphoglycerate

Phosphoglycerate is a biochemically significant 3-carbon molecule that is a metabolic intermediate in both glycolysis and the Calvin cycle. This chemical compound is a glycerate, a sub-category of sugar acids, which are in turn a subset of the sugar family. Phosphoglycerate is vital in the processes of life as it is involved in the metabolic pathway that converts glucose into pyruvate in the process of glycolysis.

Structure and Properties

Phosphoglycerate is a 3-carbon molecule. It has a phosphate group attached to the third carbon atom in the molecule. This phosphate group is negatively charged, making phosphoglycerate an anion. The molecule also has a carboxyl group attached to the second carbon atom, which is also negatively charged.

Role in Metabolic Pathways

Glycolysis is the metabolic pathway that converts glucose into pyruvate. The free energy released in this process is used to form the high-energy molecules ATP (adenosine triphosphate) and NADH (nicotinamide adenine dinucleotide). Phosphoglycerate is a key intermediate in this process.

In the Calvin cycle, phosphoglycerate is also an important intermediate. The Calvin cycle is the set of chemical reactions that occur in chloroplasts during photosynthesis. The cycle is light-independent because it takes place after the energy has been captured from sunlight.

Medical Significance

Phosphoglycerate has been implicated in several diseases, including cancer. In cancer cells, the enzyme phosphoglycerate mutase is often overexpressed. This enzyme catalyzes the conversion of 3-phosphoglycerate to 2-phosphoglycerate, a step in the glycolytic pathway. This overexpression may contribute to the "Warburg effect", a phenomenon in which cancer cells predominantly produce energy by a high rate of glycolysis followed by lactic acid fermentation in the cytosol, rather than by a comparatively low rate of glycolysis followed by oxidation of pyruvate in mitochondria as in most normal cells.