Hemoglobin Dallas (α97(G4)Asn→Lys):functional characterization of a high oxygen affinity natural mutant
| Autor: | Beatrice Vallone, Gino Amiconi, Andrea Bellelli, G.V. Sciarratta, C. Castello, S. Tomova, Rodolfo Ippoliti, Eugenio Lendaro, G. Ivaldi, Maurizio Brunori, Andrea Brancaccio |
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| Rok vydání: | 1992 |
| Předmět: |
Models
Molecular Bezafibrate Chemistry Stereochemistry Hemoglobins Abnormal Allosteric regulation Hemoglobin variants Bohr effect Cooperativity Abnormal hemoglobin Oxygen Kinetics Allosteric Regulation Biochemistry Mutation medicine Humans Molecular Medicine Asparagine Hemoglobin Molecular Biology medicine.drug |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease. 1180:15-20 |
| ISSN: | 0925-4439 |
| DOI: | 10.1016/0925-4439(92)90021-e |
| Popis: | Hemoglobin Dallas, an α-chain variant with a substitution of lysine for asparagine at position 97(G4), was found to have increased oxygen affinity ( p 1 2 = 1 mmHg at pH 7.3 and 20°C), diminished cooperativity (0n, the Hill coefficient = 1.7 ) and reduced Bohr effect (about 50%). Addition of allosteric effectors (such as 2,3-diphosphoglycerate, inositol hexakisphosphate and bezafibrate) led to a decrease in oxygen affinity and increase in cooperative energy. Kinetic studies at pH 7.0 and 20°C revealed that (i), the overall rate of oxygen dissociation is 1.4-fold slower than that for HbA and (ii), the carbon monoxide dissociation rate is unaffected. The abnormal properties of this hemoglobin variant can be atttributed to a more ‘relaxed’ T-state. |
| Databáze: | OpenAIRE |
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