title: An extended Monod-Wyman-Changeaux-model expressed in terms of the Herzfeld-Stanley formalism applied to oxygen and carbonmonoxide binding curves of hemoglobin trout IV.
abstract: An extended Monod, Wyman, Changeaux (MWC)-model, the mathematical basis of which had been formulated by Herzfeld and Stanley (J. Mol. Blol. 82:231. 1974.) was used to fit oxygen and CO-binding curves of hemoglobin trout IV measured at different pH-values between pH = 8.0 and 6.0. From this calculation one obtains that even the fully liganded molecule exhibits a R----T quaternary transition upon approaching the acid pH-region. In the case of O2-binding, the cooperativity becomes negative below pH = 6.5. This can be related to the difference between the equilibrium constants of proton binding to the alpha- and beta-subunits. Furthermore, it can be shown that the interaction between the quaternary T----R- and the tertiary t----r-transitions is different for the alpha- and beta-subunits.
authors.affiliation: University of Bremen, FB 1-Physics Department, Federal Republic of Germany.
authors.forename: R
authors.initials: R
authors.lastname: Schweitzer-Stenner
authors.forename: W
authors.initials: W
authors.lastname: Dreybrodt
mesh_terms: D000818:Animals; D002248:Carbon Monoxide / Q000097:blood*; D002263:Carboxyhemoglobin / Q000378:metabolism*; D006454:Hemoglobins / Q000378:metabolism*; D007700:Kinetics; D008024:Ligands; D008433:Mathematics; D008962:Models, Theoretical; D010100:Oxygen / Q000097:blood*; D010108:Oxyhemoglobins / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D013816:Thermodynamics; D014337:Trout
chemical_list: D006454:Hemoglobins; D008024:Ligands; D010108:Oxyhemoglobins; D002248:Carbon Monoxide; D002263:Carboxyhemoglobin; D010100:Oxygen