The Binding of Asparagine,Glutamine and Homoserine to Human Erythrocytes Containing Hemoglobins S and CS and to Soluble Hemoglobins S and CS |
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Authors: | N M Rumen A Chrambach |
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Institution: | 1. National Institutes of Child Health &2. Human, Development National Institutes of Health , Bethesda, Md., 20014;3. Laboratory of Immunology , Albert Einstein Medical Center , York and Tabor Roads, Philadelphia, Pa., 19141 |
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Abstract: | Abstract Tritium labeled asparagine binds to oxyhemoglobin S and to a mixture of hemoglobins C and S in the molar ratio of 3.38:1 and 8.2:1 respectively. From the dialysis equilibrium studies it appears that labeled asparagine does not bind to oxy- or deoxy- hemoglobin A nor to deoxyhemoglobin S. The constant for equilibrium association of asparagine for oxyhemoglobin S is 7.38 × 107 M?1 and for'oxyhemoglobin CS 4.8 × 104 M?1 at 23°C. Tritium labeled asparagine is bound to oxyhemoglobin S and CS sufficiently strongly to prevent dissociation under the conditions of gel electrophoresis at pH 9.50. The protein with and without bound asparagine, gluta-mine or homoserine, is indistinguishable in molecular net charge and size by the criteria of quantitative polyacrylamide gel electrophoresis (PAGE). Also there were no significant differences in mobility between hemoglobin S and hemoglobin C in the presence and absence of asparagine, glutamine and homoserine as detectable in agar coated cellulose acetate electrophoresis at pH 6.3. Erythrocytes containing hemoglobin S and CS, after incubation with tritium labeled asparagine and lysis under the conditions of gel electrophoresis at pH 9.5, release hemoglobin S and C with bound tritiated asparagine. No tritiated asparagine remains bound to the ghost. |
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