A thermodynamic model of hemoglobin suitable for physiological applications.
We propose a quantitative model of the thermodynamics of hemoglobin in contact with its five major ligands (O2, CO2, Cl-, 2,3-bisphosphoglycerate, and H+). Our model incorporates the two-state formalism of J. Monod, J. Wyman, and J.P. Changeux (J. Mol. Biol. 12: 88-118, 1965) for treatment of quanternary transitions and also the mean field formalism of K. Linderstrom-Lang (C. R. Trav. Lab. Carlsberg Ser. Chim. 15: 1-30, 1924) for treatment of electrostatic interactions. On the basis of this approach, we develop an algorithm for the efficient computation of observable quantities, such as the occupancy of various ligand binding sites, and an objective statistical procedure for determining both maximum likelihood values and confidence limits of all the intrinsic thermodynamic parameters of hemoglobin. Finally, we show that the predictions of our theory are in good agreement with independent experimental observations.
Yoshida
T
T
Isotope and Structural Chemistry, Group INC-4, Los Alamos National Laboratory, New Mexico 87545.
Dembo
M
M
D002245:Carbon Dioxide / Q000097:blood; D006454:Hemoglobins / Q000502:physiology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008024:Ligands; D008433:Mathematics; D008954:Models, Biological; D009994:Osmolar Concentration; D010108:Oxyhemoglobins / Q000378:metabolism; D013816:Thermodynamics
D006454:Hemoglobins; D008024:Ligands; D010108:Oxyhemoglobins; D002245:Carbon Dioxide