Carbon monoxide is a dangerous molecule to inhale. In your blood stream, carbon monoxide can get into your cells and bond tightly with iron, a co-factor of an important enzyme in the production of ATP. Without this enzyme function ATP cannot be formed. Why can’t the enzyme function? Answer- A. The enzyme substrate complex cannot be formed. B. The carbon monoxide prevents oxygen from getting into the lungs. C. It still can, once it causes the carbon monoxide to undergo a reaction.