Osmotic pressure measurements of the ligand-linked dissociation equilibrium of human oxyhemoglobin.
The tetramer/dimer equilibrium of human oxyhemoglobin has been measured by an osmometric method as a function of pH, chloride and 2,3-bisphosphoglycerate concentrations at 21 degrees C. The binding constants of chloride and 2,3-bisphosphoglycerate to the tetramer and the dimer were thus evaluated at various pH values. 2,3-Bisphosphoglycerate is bound to the dimer more strongly than to the tetramer. The dimer has a second binding site for 2,3-bisphosphoglycerate. The data for 2,3-bisphosphoglycerate binding were corroborated by direct binding measurements with the ultrafiltration method.
Abteilung für Biopolymere, RWTH Aachen, Federal Republic of Germany.
H
H
Schönert
B
B
Stoll
D019794:2,3-Diphosphoglycerate; D001665:Binding Sites; D002712:Chlorides / Q000378:metabolism; D004163:Diphosphoglyceric Acids / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D008433:Mathematics; D009997:Osmotic Pressure; D010108:Oxyhemoglobins / Q000378:metabolism*
D002712:Chlorides; D004163:Diphosphoglyceric Acids; D008024:Ligands; D010108:Oxyhemoglobins; D019794:2,3-Diphosphoglycerate