The role of the carbon skeleton of lysine in the biosynthesis of hemoglobin

1. 1. It has been shown that lysine-ϵ-C 14 , led to a dog, contributes significantly to the biosynthesis of the protoporphyrin IX in erythrocyte hemoglobin. 2. 2. The C 14 -activity of such hemoglobin protoporphyrin was found to be localized largely in carbon atoms C -10 and D -10 as ascertained by isolation of the two carbon atoms in question by means of the Schmidt reaction. 3. 3. A comparison of the specific millimolar C 14 -activities of protoporphyrin IX, and of glutamic and aspartic acids isolated from erythrocyte globin, suggests that the conversion of the carbon skeleton of lysine to the afore-mentioned metabolites occurs without preceding fragmentation through a five carbon intermediary metabolite which may be identical with α-ketoglutarate.