Weber, Roy E.4; Hiebl, Inge2; Braunitzer, Gerhard3
1 Department of Bioscience - Zoophysiology, Department of Bioscience, Science and Technology, Aarhus University2 Max Planck Institute of Biochemistry3 unknown4 Department of Bioscience - Zoophysiology, Department of Bioscience, Science and Technology, Aarhus University
Functional characteristics of the stripped composite hemoglobins (Hbs) of lhevultures Gyps rueppellii and Aegypills monachus that can fly at extremely high altitudes, and of component Hbs of G. rueppellii are reported, in relation to influences of pH, temperalure and inositol hexaphosphate. G. rueppellii Hbs A, A' and D represent a sequence of increasing oxygen affinity, which is opposite to earlier results onavian Hb components, but correlates with two a-chain substitutions that predictably affect oxygen affinity. The homo- and heterotropic interactions in oxygen binding are related to primary structures of the constituent polypeptide chains to trace molecular adaptations to high-altitude respiration, and to physiological factors (pulmonary hypoxia and hypocapnia, body temperature shifts, and lung and nasal gas and heat exchange) to discern their possible survival value at altitudes of 11300 m.
Biological Chemistry Hoppe-seyler, 1988, Vol 369, p. 233-240