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arXiv · 2402.17796

An Allosteric Model for the Influence of $\text{H}^+$ and $\text{CO}_2$ on Oxygen-Hemoglobin Binding

Heming Huang·Charles S. Peskin
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Abstract

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.

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Heming Huang, Charles S. Peskin. 2024-02-26. An Allosteric Model for the Influence of $\text{H}^+$ and $\text{CO}_2$ on Oxygen-Hemoglobin Binding. https://arxiv.org/abs/2402.17796

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