Bisphosphorylated metabolites of glycerate, glucose, and fructose: functions, metabolism and molecular pathology

2,3-Bisphosphoglycerate, glucose 1,6-P2 and fructose 2,6-P2 have been recognized as regulatory signals implicated in the control of metabolism, oxygen affinity of red cells and other cellular functions. The alterations of their metabolism constitute a novel area in molecular pathology. The concentration of 2,3-bisphosphoglycerate in erythrocytes changes in a number of pathological conditions. An inherited deficiency of the multifunctional enzyme involved in the synthesis and breakdown of 2,3-bisphosphoglycerate in erythrocytes has been reported. The levels of glucose 1,6-P2 are reduced in the liver and in the muscle of rats with experimentally induced diabetes. In muscle of genetically dystrophic mice a decrease in the levels of glucose 1,6-P2 has been found, probably resulting from enhancement of glucose 1,6-P2 phosphatase activity. Fructose 2,6-P2 levels are decreased in the liver of experimental diabetic mice and rats, and elevated in the liver of genetically obese animals.