di·phos·pho·gly·cer·ic acid 
(dī-fŏs′fō-glĭ-sĕrĭk)
(dī-fŏs′fō-glĭ-sĕrĭk)n.
Either of two isomers that are diphosphates of glyceric acid. 1,3-diphosphoglyceric acid is an important intermediate in glycolysis and other metabolic pathways. 2,3-diphosphoglyceric acid affects the binding of oxygen to hemoglobin in red blood cells.