An Allosteric Model for the Influence of $\text{H}^+$ and $\text{CO}_2$ on Oxygen-Hemoglobin Binding
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arXiv
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| Format: | Preprint |
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2024
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| _version_ | 1866929258188767232 |
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| author | Huang, Heming Peskin, Charles S. |
| author_facet | Huang, Heming Peskin, Charles S. |
| contents | In the physiology of oxygen-hemoglobin binding, an important role is played by the influence of $\text{H}^+$ and $\text{CO}_2$ on the affinity of hemoglobin for $\text{O}_2$. Here we extend the allosteric model of hemoglobin to include these effects. We assume purely allosteric modulation, i.e., that the modulatory effects of $\text{H}^+$ and $\text{CO}_2$ on oxygen binding occur only because of their influence on the T $\leftrightarrow$ R transition, in which all four subunits of the hemoglobin molecule participate simultaneously. We assume, moreover, that these modulatory influences occur only through the interaction of $\text{H}^+$ and $\text{CO}_2$ with the amino group at the N-terminal of each of the four polypeptide chains of the hemoglobin molecule. We fit the model to experimental data and obtain reasonable agreement with the observed shifts in oxygen-hemoglobin binding that occur when the concentrations of $\text{H}^+$ and $\text{CO}_2$ are changed. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2402_17796 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | An Allosteric Model for the Influence of $\text{H}^+$ and $\text{CO}_2$ on Oxygen-Hemoglobin Binding Huang, Heming Peskin, Charles S. Biological Physics Chemical Physics Biomolecules In the physiology of oxygen-hemoglobin binding, an important role is played by the influence of $\text{H}^+$ and $\text{CO}_2$ on the affinity of hemoglobin for $\text{O}_2$. Here we extend the allosteric model of hemoglobin to include these effects. We assume purely allosteric modulation, i.e., that the modulatory effects of $\text{H}^+$ and $\text{CO}_2$ on oxygen binding occur only because of their influence on the T $\leftrightarrow$ R transition, in which all four subunits of the hemoglobin molecule participate simultaneously. We assume, moreover, that these modulatory influences occur only through the interaction of $\text{H}^+$ and $\text{CO}_2$ with the amino group at the N-terminal of each of the four polypeptide chains of the hemoglobin molecule. We fit the model to experimental data and obtain reasonable agreement with the observed shifts in oxygen-hemoglobin binding that occur when the concentrations of $\text{H}^+$ and $\text{CO}_2$ are changed. |
| title | An Allosteric Model for the Influence of $\text{H}^+$ and $\text{CO}_2$ on Oxygen-Hemoglobin Binding |
| topic | Biological Physics Chemical Physics Biomolecules |
| url | https://arxiv.org/abs/2402.17796 |