Carp hemoglobin. II. The alkaline Bohr effect.

摘要: The Bohr effect of carp hemoglobin has been determined by differential titration, direct acid-base and calculation from precise oxygen equilibrium data over a wide pH variation. results for the hemolysate two major components are essentially identical. At 6.9 in vicinity maximum cooperativity effect, protein releases 3.7 protons absence added ions. This curve above 7 is not changed presence 0.05 M 2,2-bis(hydroxymethyl)-2,2',2"-nitrilotriethanol (bis-Tris) buffer, but below pK bis-Tris amine, giving 4.3 at 6.65. In 0.1 phosphate, increased to 6.1 shifted 7.25. Addition 1.4 mM P6-inositol lowers magnitude shifts its an even higher pH. limit high (9.02), without buffer or bis-Tris, there net uptake about 0.5 proton upon oxygenation. average heat ionization groups 5500 +/- 800 cal. Even though chloride ion pronounced on oxygenation properties hemoglobin, it small influence up NaCl. 5 NaCl, reduced approximately 30%., Acid base titrations give three four oxygen-linked water; this six 2.5 suggest that functionally versatile may provide one way regulate CO2 transport via heterotropic allosteric interactions. phosphate value where strongly cooperative, release linear with respect ligand saturation. Lowering either increase decrease nonlinear relationships.