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Lacking deoxygenation‐linked interaction between cytoplasmic domain of band 3 and HbF from fetal red blood cells
Author(s) -
Weber R. E.
Publication year - 2007
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/j.1748-1716.2007.01736.x
Subject(s) - band 3 , glycolysis , fetal hemoglobin , red blood cell , red cell , deoxygenation , fetus , chemistry , biochemistry , biophysics , membrane , biology , metabolism , membrane protein , medicine , pregnancy , genetics , catalysis
Aim: Several of the red blood cell’s metabolic and membrane functions display dependence on haemoglobin oxygenation. In adult human red cells, the increased glycolytic rate at low O 2 tension results from binding of deoxygenated HbA at negatively charged, N‐terminal, cytoplasmic domain of the membrane protein band 3, which liberates glycolytic enzymes from this site. This study aims to investigate the role of fetal HbF (that has lower anion‐binding capacity than HbA) in fetal red cells (that are subjected to low O 2 tensions), and to elucidate possible linkage (e.g. via the major red cell membrane organising centre, band 3) between the individual oxygenation‐linked reactions encountered in red cells. Methods: The interaction between band 3 and Hb is analysed in terms of the effects, measured under different conditions, of a 10‐mer peptide that corresponds to the N‐terminus of human band 3 protein, on the oxygenation reaction of HbF and HbA, isolated from umbilical chord red cells. Results: Contrasting with the unequivocal interaction of the peptide with HbA that with fetal HbF is weak, and annihilated in the presence of autochthonous red cell O 2 affinity modulators (chloride and organic phosphates). Conclusion: The data indicate that HbF does not function as a transducer mediating O 2 dependence of glycolysis in fetal red cells, in accordance with the different O 2 and metabolic profiles compared to those in HbA‐bearing adult red cells. In conjunction with the previously discovered O 2 dependence of K + transport in HbF‐rich fetal cells, they moreover argue against linkage between different, physiologically relevant, O 2 ‐dependent red cell functions.