High-altitude respiration of falconiformes. The primary structures and functional properties of the major and minor hemoglobin components of the adult White-Headed Vulture (Trigonoceps occipitalis, Aegypiinae).
The primary structures of the hemoglobin components Hb A and Hb D of White-Headed Vulture (Trigonoceps occipitalis) are presented. The globin chains were separated on CM-Cellulose in 8M urea buffer, the components by FPLC in phosphate buffers. The amino-acid sequences were established by automatic Edman degradation of the globin chains and of the tryptic peptides in liquid phase and gas-phase sequenators. The sequences differ from those of European Black Vulture by only one mutation in the alpha A-chains (alpha 137). The alpha D-chains and the beta-chains are identical. This means that for the first time identical minor components in birds have been found. An updated list of identical globin chains is presented. Hb D exhibited a higher oxygen affinity than Hb A. At pH 7.5 and 38 degrees C P50 values of 0.80 and 0.64 kPa (6.0 and 4.8 mm Hg), respectively. Both hemoglobins showed similar Bohr factors displayed a pronounced sensitivity to inositol hexakis(phosphate), which increased P50 values of Hbs A and D to 4.0 and 3.6 kPa (30 and 26 mm Hg), respectively. The molecular and physiological significance of the findings is discussed with special reference to oxygen transport by hemoglobin at high altitude.
Max-Planck-Institut für Biochemie, Abt. Proteinchemie, Martinsried bei München.
I
I
Hiebl
R E
RE
Weber
D
D
Schneeganss
G
G
Braunitzer
D000531:Altitude; D000595:Amino Acid Sequence; D000818:Animals; D001717:Birds / Q000097:blood*; D004912:Erythrocytes / Q000032:analysis / Q000378:metabolism; D005914:Globins / Q000032:analysis; D006454:Hemoglobins / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D010101:Oxygen Consumption; D010446:Peptide Fragments / Q000032:analysis; D011487:Protein Conformation; D014357:Trypsin
D006454:Hemoglobins; D010446:Peptide Fragments; D005914:Globins; D014357:Trypsin