Oxygen binding constants for human hemoglobin tetramers
- 30 June 1987
- journal article
- research article
- Published by American Chemical Society (ACS) in Biochemistry
- Vol. 26 (13), 3995-4002
- https://doi.org/10.1021/bi00387a038
Abstract
High-precision studies of oxygen binding in hemoglobin (HbA0) solutions at near-physiological concentrations (2-12 mM heme; pHs 7.0-9.1; various buffers) have led to an unanticipated result: an unmeasurably low contribution from the triply ligated species. We have obtained this result from new differential oxygen-binding measurements for human hemoglobin through the use of a thin-layer apparatus, which enables study of solutions at high Hb concentrations. The effect of tetramer dissociation into dimers, which becomes significant at hemoglobin concentrations below 1 mM in heme, is avoided. The analysis of the binding reactions is thus cast in terms of the tetramer-binding polynomial written with overall Adair equilibrium constants which directly reflect the contributions of intermediate ligated species. The unmeasurable contribution of the triply ligated species renders the equilibrium constants of the third and fourth stepwise reactions practically undeterminable.This publication has 12 references indexed in Scilit:
- Ligand-linked phase equilibria of sickle cell hemoglobinJournal of Molecular Biology, 1980
- Oxygen binding to sickle cell hemoglobinJournal of Molecular Biology, 1979
- Quaternary enhancement in binding of oxygen by human hemoglobinProceedings of the National Academy of Sciences, 1979
- Aggregation Effects on Oxygen Binding of Sickle Cell HemoglobinScience, 1978
- Membrane-covered thin-layer optical cell for gas-reaction studies of hemoglobinAnalytical Biochemistry, 1978
- Role of Bohr group salt bridges in cooperativity in hemoglobinBiochimica et Biophysica Acta (BBA) - Protein Structure, 1978
- The hemoglobin-oxygen equilibrium associated with sub-unit dissociation I. An approach with the hill schemeBiochimica et Biophysica Acta (BBA) - Protein Structure, 1977
- Oxygenation-linked subunit interactions in human hemoglobin: experimental studies on the concentration dependence of oxygenation curvesBiochemistry, 1976
- Oxygenation-linked subunit interactions in human hemoglobin: analysis of linkage functions for constituent energy termsBiochemistry, 1976
- Effect of organic and inorganic phosphates on the oxygen equilibrium of human erythrocytesArchives of Biochemistry and Biophysics, 1967