Biomaterial Database

pH dependence of 2,3-diphosphoglycerate binding to human hemoglobin A0 at 21.5 degrees C. 1986

M K Hobish, and D A Powers

Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218.

Rate equilibrium dialysis was used to measure the binding of 2,3-diphosphoglycerate (DPG) to human oxy- and deoxyhemoglobin A0 over the range pH 5-9, at 21.5 degrees C. This approach yielded an accurate, precise, and self-consistent set of model-independent association constants. These data were successfully fitted to a thermodynamic model which is functionally similar to a Hill equation. The isotherms generated by this fitting procedure appear to intersect at low pH and converge at high pH. This apparent convergence at high pH is consistent with results obtained by oxygen equilibria studies performed under conditions of saturating DPG. These calculated isotherms were used to determine the enhancement of the Bohr effect as a function of pH. These results are consistent with data obtained by pH stat measurements by other investigators. This paper presents the first in a series of studies that will provide a systematic characterization of the interaction between hemoglobin and DPG.

UI	MeSH Term	Description	Entries
D008956	Models, Chemical	Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.	Chemical Models,Chemical Model,Model, Chemical
D010108	Oxyhemoglobins	A compound formed by the combination of hemoglobin and oxygen. It is a complex in which the oxygen is bound directly to the iron without causing a change from the ferrous to the ferric state.	Oxycobalt Hemoglobin,Oxycobalthemoglobin,Oxyhemoglobin,Hemoglobin, Oxycobalt
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D011522	Protons	Stable elementary particles having the smallest known positive charge, found in the nuclei of all elements. The proton mass is less than that of a neutron. A proton is the nucleus of the light hydrogen atom, i.e., the hydrogen ion.	Hydrogen Ions,Hydrogen Ion,Ion, Hydrogen,Ions, Hydrogen,Proton
D004163	Diphosphoglyceric Acids	Glyceric acids where two of the hydroxyl groups have been replaced by phosphates.	Bisphosphoglycerates,Acids, Diphosphoglyceric
D006441	Hemoglobin A	Normal adult human hemoglobin. The globin moiety consists of two alpha and two beta chains.
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D013696	Temperature	The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.	Temperatures
D013816	Thermodynamics	A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)	Thermodynamic