Iron Protoporphin to Bile Pigments

This process has been studied intensively, especially in connection with the breakdown of the hemoglobin of red blood cells to bile pigments, and our knowledge of the chemical steps taking place has been due primarily to Fischer and Libowitzky (40), Siedel (118,119), Watson (154,155), and Lemberg. 

Denatured globin-ferroheme 4- O2------- denatured globin-ferriheme + HjO (1) 

Denatured globin-ferriheme -+ reducing mechanism of the cell-----  

The heme molecule, once its normal iron linkage to globin is disrupted, thus has the property of catalytically destroying more hemoglobin. The importance of the peroxidative property of heme in this process becomes evident when one compares the action of 0.5% hydrogen peroxide on ferriheme and on protoporphin at pH 10. Under the same conditions, heme is destroyed within a few minutes whereas protoporphin is unaffected. If, however, a mixture of heme and protoporphin is treated with hydrogen peroxide as above, both are rapidly destroyed (50). 

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