Oxygen-Hemoglobin System: A Model for Facilitated Membranous Transport

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Science  20 Aug 1965:
Vol. 149, Issue 3686, pp. 874-876
DOI: 10.1126/science.149.3686.874


Enhanced transport of oxygen in a Millipore filter containing a solution of hemoglobin can be accounted for by the diffusion of free oxygen as well as of hemoglobin-bound oxygen. A model shows that, at oxygen tensions at which the hemoglobin is fully saturated in a portion of the membrane, the enhanced transport is due to a steeper gradient for free oxygen, whereas in the rest of the membrane an "(oxy)hemoglobin shuttle" operates. A similar model may be useful for explaining facilitated diffusion in other systems.