Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oxygen equilibrium curves (OEC) for human red blood cells (RBC) have revealed a large asymmetry with an nmax value reached at approximately 90% saturation. This contrasts with the symmetrical shape of the OEC for diluted HbA solutions. We prepared resealed red blood cells (RRBC) through controlled hemolysis and resealing in order to obtain a low Hb concentration (approximately equal to 60 g/L) and DPG/Hb4 molar ratio ranging from 0.2 to 4. When the DPG/Hb4 was close to unity, OEC still showed a large asymmetry. On the contrary, the OEC became symmetrical when DPG/Hb4 was either negligible or 3-4 fold the normal value. The asymmetrical OEC for intact RBC can be fitted with a theoretical model taking into account the variations of free DPG concentration during oxygenation. We conclude that the asymmetrical shape of OEC observed in intact fresh RBC is not due to the high protein concentration present in the RBC but to a functional heterogeneity of Hb due to the changes of the free 2,3-diphosphoglycerate (DPG) concentration during oxygenation.
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PMID:Functional properties of hemoglobin in human red cells. I. Oxygen equilibrium curves and DPG binding. 360 19

Double-headed aspirin [bis(3,5-dibromosalicyl)fumarate] selectively cross-links hemoglobin molecules between Lys 82 beta 1 and Lys 82 beta 2 and increases solubility of deoxy-Hb S (Walder et al., J. Mol. Biol., 141:195, 1980 and Kikugawa et al., J. Biol. Chem., 257:7525, 1982). We reacted this reagent with the mixture of Hb A and Hb S and the mixture of Hb S and Hb York (beta 146His replaced by Pro). Cross-linked asymmetrical hybrid hemoglobins (alpha 2 beta - beta S and alpha 2 beta Y - beta S) were produced in high yields in addition to the cross-linked parent hemoglobin molecules. Results on electrophoresis, gel electrofocusing, ion exchange column chromatography, mechanical stability and oxygen binding properties showed that the cross-linked asymmetrical hybrid hemoglobins had properties intermediate between those of the cross-linked parent hemoglobins. Oxygen affinities of the cross-linked asymmetrical hybrids were not affected by the addition of 2,3-diphosphoglycerate (DPG) or inositol hexaphosphate, probably due to the presence of a fumaryl group at the DPG binding site.
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PMID:Formation of cross-linked asymmetrical hybrid hemoglobins by double-headed aspirin. 666 87