Vitamins, Harmones and Hemoglobin
The catabolism of hemoglobin:
|A||Occurs in red blood cells.|
|B||Involves the oxidative cleavage of the porphyrin ring.|
|C||Results in the liberation of carbon dioxide.|
|D||Results in the formation of protoporphyrinogen.|
a. The cyclic heme molecule is oxidatively cleaved to form biliverdin. The catabolism occurs in the cells of the reticuloendothelial system, particularly the spleen, and results in the liberation of carbon monoxide.
b. Protoporphyrinogen is an intermediate in the synthesis, not degradation, of heme. Hemoglobin and tissue cytochromes are precursors of bilirubin.