2,3-bisphospho-D-glycerate

2,3-Bisphosphoglyceric acid

Names
IUPAC name 2,3-diphosphonooxypropanoic acid
Other names 2,3-Diphosphoglyceric acid; 2,3-Diphosphoglycerate; 2,3-Bisphosphoglycerate
Identifiers
CAS Number	138-81-8
3D model (JSmol)	Interactive image
Abbreviations	2,3-BPG; 2,3-DPG; 23BPG
ChEBI	CHEBI:17720 Y
ChemSpider	161681 Y 60 (Racemic) Y
PubChem CID	61
InChI InChI=1S/C3H8O10P2/c4-3(5)2(13-15(9,10)11)1-12-14(6,7)8/h2H,1H2,(H,4,5)(H2,6,7,8)(H2,9,10,11)/t2-/m1/s1 Y Key: XOHUEYCVLUUEJJ-UWTATZPHSA-N Y Key: XOHUEYCVLUUEJJ-UWTATZPHBL
SMILES O=P(O)(OC(C(=O)O)COP(=O)(O)O)O
Properties
Chemical formula	C3H8O10P2
Molar mass	266.03 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
(what is Y ?)
Infobox references

2,3-Bisphosphoglyceric acid (conjugate base 2,3-bisphosphoglycerate) (2,3-BPG), also known as 2,3-diphosphoglyceric acid (conjugate base 2,3-diphosphoglycerate) (2,3-DPG), is a three-carbon isomer of the glycolytic intermediate 1,3-bisphosphoglyceric acid (1,3-BPG). 2,3-BPG is present in human red blood cells (RBC; erythrocyte) at approximately 5 mmol/L. It binds with greater affinity to deoxygenated hemoglobin (e.g. when the red blood cell is near respiring tissue) than it does to oxygenated hemoglobin (e.g., in the lungs) due to spatial changes: 2,3-BPG (with an estimated size of about 9 angstroms) fits in the deoxygenated hemoglobin configuration (11 angstroms), but not as well in the oxygenated (5 angstroms). It interacts with deoxygenated hemoglobin beta subunits by decreasing their affinity for oxygen, so it allosterically promotes the release of the remaining oxygen molecules bound to the hemoglobin, thus enhancing the ability of RBCs to release oxygen near tissues that need it most. 2,3-BPG is thus an allosteric effector.

Its function was discovered in 1967 by Reinhold Benesch and Ruth Benesch.

2,3-BPG is formed from 1,3-BPG by the enzyme BPG mutase. It can then be broken down by 2,3-BPG phosphatase to form 3-phosphoglycerate. Its synthesis and breakdown are, therefore, a way around a step of glycolysis, with the net expense of one ATP per molecule of 2,3-BPG generated as the high-energy carboxylic acid-phosphate mixed anhydride bond is cleaved by bisphosphoglycerate mutase.

The normal glycolytic pathway generates 1,3-BPG, which may be dephosphorylated by phosphoglycerate kinase (PGK), generating ATP, or it may be shunted into the Luebering-Rapoport pathway, where bisphosphoglycerate mutase catalyzes the transfer of a phosphoryl group from C1 to C2 of 1,3-BPG, giving 2,3-BPG. 2,3-BPG, the most concentrated organophosphate in the erythrocyte, forms 3-PG by the action of bisphosphoglycerate phosphatase. The concentration of 2,3-BPG varies proportionately to the [H+], which is inhibitory to catalytic action of bisphosphoglycerate phosphatase.