An intermediate in the Rapaport-Luebering shunt, formed between 1,3-P2Gri and 3-phosphoglycerate; an intermediate ofphosphoglycerate mutase. It is found in RBCs at nearly same concentration as hemoglobin. It is responsable for loweringthe oxygen affinity of hemoglobin to more efficiently release oxygen at typical P02 of tissues. One molecule of2,3-DPGinteracts with each hemoglobin tetramer. A rise of2,3-BPG in RBCs promotes the shift of hemoglobin to the Tform and thsubsequent release of oxygen (as in tissue hypoxia from anemia, high altitudes or pulmonary dysfunction etc.) Duringblood storage 2,3-BPG levels fall. Syn: 2,3-P2Gri.