Luebering–Rapoport pathway

Pathway of generation of 2,3-bisphosphoglycerate

The Luebering–Rapoport pathway is a metabolic pathway involved in the breakdown of glucose in red blood cells. It is also known as the Embden–Meyerhof–Parnas pathway, which is the main pathway of glycolysis. The Luebering–Rapoport pathway consists of a series of enzymatic reactions that convert glucose into pyruvate, producing ATP and NADH in the process.

The pathway begins with the phosphorylation of glucose by the enzyme hexokinase, forming glucose-6-phosphate. This molecule is then converted to fructose-6-phosphate by the enzyme glucose-6-phosphate isomerase. Fructose-6-phosphate is further phosphorylated to fructose-1,6-bisphosphate by the enzyme phosphofructokinase-1.

The next step involves the cleavage of fructose-1,6-bisphosphate into two three-carbon molecules: glyceraldehyde-3-phosphate and dihydroxyacetone phosphate. This reaction is catalyzed by the enzyme aldolase. Glyceraldehyde-3-phosphate is then converted to 1,3-bisphosphoglycerate by the enzyme glyceraldehyde-3-phosphate dehydrogenase, generating NADH in the process.

Subsequently, 1,3-bisphosphoglycerate is converted to 3-phosphoglycerate by the enzyme phosphoglycerate kinase, producing ATP. The pathway continues with the conversion of 3-phosphoglycerate to 2-phosphoglycerate by the enzyme phosphoglycerate mutase, followed by the conversion of 2-phosphoglycerate to phosphoenolpyruvate by the enzyme enolase.

The final step of the Luebering–Rapoport pathway involves the conversion of phosphoenolpyruvate to pyruvate by the enzyme pyruvate kinase, generating ATP. Pyruvate can then enter the citric acid cycle or be converted to lactate under anaerobic conditions.

Overall, the Luebering–Rapoport pathway plays a crucial role in energy production and the metabolism of glucose in red blood cells.