Carbon monoxide heme catabolism producing

Bilirubin and carbon monoxide are always produced in equimolar proportions under normal conditions of heme catabolism the process is oxidative and requires molecular oxygen. Labelling studies using 02 show that the labelled oxygen ends up in the bilirubin at the terminal lactam positions, and in the carbon monoxide that is liberated (by removal of the C-5 carbon). The overall process is shown in Figure 5.5. 

Not only is carbon monoxide produced during catabolism of hemes, but it is also necessary for maintenance of neuronal function and cell signaling in the vasculature and therefore is present normally in the vicinity of Mb and Hb. For synthetic systems of picket-fence, pocket, or capped porphyrins, CO affinity exceeds that for O2 sometimes by many orders of magnitude. The in... 

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