A comparative study on the phosphoglyceric acid cycle in mammalian erythrocytes

1. 1. The activities of the enzymes and intracellular concentrations of substrates and cofactors associated with phosphoglyceric acid metabolism in erythrocytes of nine mammals are reported. 2. 2. In every case 2,3-DPG phosphatase activity was lower than that of the other enzymes measured: glyceraldehyde phosphate dehydrogenase, diphosphoglycerate mutase, phosphoglycerate kinase and phosphoglycerate mutase. 3. 3. The red blood cells of man, rabbit, dolphin and pig contain high concentrations of 2,3-DPG and ATP whereas bovine, caprine and feline erythrocytes contain little of either compound. Equine erythrocytes contain large amounts of 2,3-DPG but little ATP. 4. 4. No 2,3-DPG and only very small amounts of diphosphoglyceric acid mutase was detected in the erythrocytes of the goat.