13bisfosfoglycerata

1,3-Bisphosphoglycerate, often abbreviated as 1,3-BPG, is a vital intermediate molecule in cellular respiration. It is formed during the third step of glycolysis, the metabolic pathway that breaks down glucose. Specifically, 1,3-BPG is produced when 3-phosphoglycerate is phosphorylated by the enzyme phosphoglycerate kinase. This reaction requires ATP and magnesium ions as cofactors.

The primary significance of 1,3-BPG lies in its high-energy phosphate bond. This bond is crucial for the subsequent step of glycolysis, where it is used to generate ATP. In the presence of the enzyme glyceraldehyde-3-phosphate dehydrogenase, 1,3-BPG is dephosphorylated, transferring a phosphate group to ADP to form ATP. This process is an example of substrate-level phosphorylation. In addition to its role in ATP production, 1,3-BPG is also a precursor for the synthesis of 2,3-bisphosphoglycerate (2,3-BPG) in red blood cells. 2,3-BPG plays a critical role in regulating oxygen binding to hemoglobin, facilitating the release of oxygen to tissues.