The majority of carbon dioxide is carried through the blood by conversion from carbon dioxide, CO₂ into bicarbonate ions, HCO₃-,which allows it to dissolve as a salt in the blood and be carried along. This reaction is catalyzed by the protein carbonic an hydrase.As carbon dioxide is a waste product of our cellular respiration, it is shuttled to the lungs, where it can come out of solution back intogas, and exit our body when we breathe out.