Changes in the enzymes related to 2,3-bisphosphoglycerate metabolism in developing erythroid cells.

Measurements of glycerate-2,3-P2 and hemoglobin in the developing erythroid cells indicated that the glycerate-2,3-P2 level rose during erythroid differentiation in a linear relationship to the hemoglobin level, suggesting the presence of regulation to accumulate both substances synchronously. The accumulation of glycerate-2,3-P2 was found to be primarily attributable to the increase in glycerate-2,3-P2 synthase activity. The activities of phosphofructokinase and pyruvate kinase changed so as to be favourable for glycerate-2,3-P2 accumulation. The increase in glycerate-2,3-P2 synthase activity was shown to be caused by an increase in the enzyme protein. Synthesis of glycerate-2,3-P2 synthase protein was proved in bone marrow erythroid cells and in reticulocytes.