Fig. 1.
Elephant in the dark no more: the binding affinities of CO toward various targets in biologic systems. Various hemoproteins with different binding affinities to CO shown as the Kd on the left scale in the elephant figure, and they are also placed on top of the mountains with the height representing their Kd values. The Kd for binding between CO and hemoglobin in the T state and R state, respectively, is marked on the right scale in the figure and overlaid on the waterfalls. As water naturally flows to a lower level than that of the waterfall, CO is more likely to transfer from hemoglobin to a hemoprotein target with a higher binding affinity (lower Kd) on the left side.