2-phosphoglycerate

2-Phosphoglycerate

2-Phosphoglycerate (2PG) is an important intermediate in the metabolic pathway of glycolysis, which is the process by which glucose is broken down to produce energy in the form of adenosine triphosphate (ATP). It is a three-carbon molecule that plays a crucial role in the conversion of glucose to pyruvate.

Structure

2-Phosphoglycerate is a phosphorylated derivative of glyceric acid. It has the chemical formula C₃H₇O₇P and consists of a glycerate backbone with a phosphate group attached to the second carbon atom. The presence of the phosphate group is essential for its role in glycolysis.

Role in Glycolysis

In the glycolytic pathway, 2-phosphoglycerate is formed from 3-phosphoglycerate through the action of the enzyme phosphoglycerate mutase. This reaction involves the transfer of the phosphate group from the third carbon to the second carbon, converting 3-phosphoglycerate to 2-phosphoglycerate.

The next step in glycolysis involves the conversion of 2-phosphoglycerate to phosphoenolpyruvate (PEP) by the enzyme enolase. This reaction is a dehydration process, where a molecule of water is removed, resulting in the formation of the high-energy compound PEP, which is a key precursor to the production of ATP.

Importance

The conversion of 2-phosphoglycerate to phosphoenolpyruvate is a critical step in glycolysis because it sets the stage for the subsequent generation of ATP. The high-energy phosphate bond in PEP is used to phosphorylate ADP to ATP in the final steps of glycolysis, catalyzed by the enzyme pyruvate kinase.

Clinical Relevance

Abnormalities in glycolysis, including the steps involving 2-phosphoglycerate, can lead to various metabolic disorders. Understanding the role of 2-phosphoglycerate and its associated enzymes is important in the study of diseases such as cancer, where glycolysis is often upregulated, and in conditions like hemolytic anemia, where glycolytic enzyme deficiencies can occur.

Also see

• Glycolysis
• Phosphoglycerate mutase
• Enolase
• Phosphoenolpyruvate
• Pyruvate kinase
• Metabolic pathway

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Glycolysis metabolic pathway

Glucose Hexokinase ATP ADP Glucose 6-phosphate Glucose-6-phosphate isomerase Fructose 6-phosphate Phosphofructokinase-1 ATP ADP Fructose 1,6-bisphosphate Fructose-bisphosphate aldolase Dihydroxyacetone phosphate + + Glyceraldehyde 3-phosphate Triosephosphate isomerase 2 × Glyceraldehyde 3-phosphate 2 ×  Glyceraldehyde-3-phosphate dehydrogenase NAD++ Pi NADH + H+ NAD++ Pi NADH + H+ 2 × 1,3-Bisphosphoglycerate 2 ×  Phosphoglycerate kinase ADP ATP ADP ATP 2 × 3-Phosphoglycerate 2 ×  Phosphoglycerate mutase 2 × 2-Phosphoglycerate 2 ×  Phosphopyruvate hydratase (enolase)   H2O   H2O 2 × Phosphoenolpyruvate 2 ×  Pyruvate kinase ADP ATP 2 × Pyruvate 2 ×