title: Activation of human erythrocyte 2,3-bisphosphoglycerate phosphatase at physiological concentrations of substrate.
abstract: In human erythrocytes the reactions of the 2,3-bisphosphoglycerate shunt are catalyzed primarily by one protein, 2,3-bisphosphoglycerate synthase-phosphatase. At low concentrations of 2,3-bisphosphoglycerate the phosphatase is activated by several anions including inorganic phosphate and sulfite, and the phosphate activation is inhibited by low concentrations of 3-phosphoglycerate [Z. B. Rose and J. Liebowitz (1970) J. Biol. Chem. 245, 3232-3241]. Phosphate and sulfite also activate at high but physiological concentrations of 2,3-bisphosphoglycerate (5 mM), but the inhibition by 3-phosphoglycerate is much weaker. The basal activity (without added phosphate or sulfite) was also found to be higher and to be 3-phosphoglycerate sensitive; this is attributed to activation either by 2,3-bisphosphoglycerate itself or by a contaminant in it. These results allow previous observations of 2,3-bisphosphoglycerate hydrolysis in intact erythrocytes to be reconciled with the properties of the purified enzyme under near-physiological conditions.
mesh_terms: D019794:2,3-Diphosphoglycerate; D004163:Diphosphoglyceric Acids / Q000097:blood; D004789:Enzyme Activation / Q000187:drug effects; D004912:Erythrocytes / Q000201:enzymology*; D006801:Humans; D006868:Hydrolysis; D010710:Phosphates / Q000494:pharmacology; D010744:Phosphoric Monoester Hydrolases / Q000097:blood* / Q000302:isolation & purification; D013447:Sulfites / Q000494:pharmacology
chemical_list: D004163:Diphosphoglyceric Acids; D010710:Phosphates; D013447:Sulfites; C019794:bisphosphoglycerate phosphatase; D019794:2,3-Diphosphoglycerate; D010744:Phosphoric Monoester Hydrolases