Functional heterogeneity and pH-dependent dissociation properties of human transferrin
| Autor: | Joseph V. Princiotto, E.J. Zapolski |
|---|---|
| Rok vydání: | 1976 |
| Předmět: |
Reticulocytes
Macromolecular Substances Iron Biophysics Ph dependent Biochemistry Dissociation (chemistry) Metal chemistry.chemical_compound Reticulocyte medicine Animals Humans Neutral ph Molecular Biology Incubation HEPES chemistry.chemical_classification Binding Sites Transferrin Hydrogen-Ion Concentration Kinetics medicine.anatomical_structure chemistry visual_art visual_art.visual_art_medium Rabbits Protein Binding |
| Zdroj: | Biochimica et biophysica acta. 428(3) |
| ISSN: | 0006-3002 |
| Popis: | Human diferric transferrin was partially labeled with 59Fe at low or neutral pH (chemically labeled) and by replacement of diferric iron previously donated to rabbit reticulocytes (biologically labeled). Reticulocyte 59Fe uptake experiments with chemically labeled preparations indicated that iron bound at near neutral pH was more readily incorporated by reticulocytes than iron bound at low pH. The pH-dependent iron dissociation studies of biologically labeled transferrin solutions indicated that Fe3+, bound at the site from which the metal was initially utilized by the cells, dissociated between pH 5.8 and 7.4. In contrast, lower pH (5.2--5.8) was required to effect dissociation of iron that has remained bound to the protein after incubation with reticulocytes. These findings suggest that each human transferrin iron-binding site has different acid-base iron-binding properties which could be related to the observed heterogenic rabbit reticulocyte iron-donating properties of human transferrin and identifies that the near neutral iron-binding site initially surrenders its iron to these cells. |
| Databáze: | OpenAIRE |
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