title: Oxygen equilibrium of hemoglobin J Cape Town.
abstract: Polycythemia in carriers of hemoglobin J Cape Town or hemoglobin Chesapeake is thought to be produced by increased oxygen affinity of their blood. Both hemoglobins involve substitution of amino acid residue alpha FG-4. Measurements reported here, of the oxygen equilibrium of purified hemoglobin J Cape Town, permit direct comparison of the two hemoglobins. J Cape Town exhibits lower oxygen affinity, and greater heme-heme interaction, than Chesapeake; both exhibit normal Bohr effects. Substitution of one polar amino acid residue for another of opposite charge (arginine --> glutamic acid) thus appears to create less disruption of the interface between alpha- and beta-chains than substitution of a nonpolar residue (arginine --> leucine).
mesh_terms: D000595:Amino Acid Sequence; D001797:Blood Protein Electrophoresis; D006418:Heme / Q000378:metabolism; D006455:Hemoglobins, Abnormal / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010100:Oxygen / Q000097:blood*; D011086:Polycythemia / Q000097:blood*
chemical_list: D006455:Hemoglobins, Abnormal; D006418:Heme; D010100:Oxygen