part of the glycolytic pathway characteristic of human erythrocytes in which 2,3-bisphosphoglycerate (2,3-P2Gri) is formed as an intermediate between 1,3-bisphosphoglycerate and 3-phosphoglycerate; 2,3-P2Gri is an important regulator of the affinity of hemoglobin for oxygen. [S. M. Rapoport, J. Luebering]