DAVID SHEMIN 



TABLE V 



Comparison of G*^ Activities of Hemin Synthesized from 5-Aminolevulinic 

 AciD-5-C*^ (0.05 mc./mM), from Glycine-2-C'* (0.05 mc./mM) and from Succinic 

 AciD-2-C'* (0.05 mc./mM) in Different Duck Red Blood Cell Preparations" 



(23,29) 



" Each preparation represented 25 ml. of duck blood prepared as previously de- 

 scribed (14,15) and contained 1 mg. of iron (ferric). 

 * Plus 0.1 mM of nonradioactive a-ketoglutaric acid. 

 ' Plus 0.33 mM of nonradioactive glycine. 



three different laboratories that a highly purified protein fraction 

 from ox liver (10), duck erythrocytes (21) and chicken erythro- 

 cytes (11) can convert 5-aminolevulinic acid to porphobilinogen. 

 In our laboratory we obtained a highly purified fraction from 

 duck blood, which on incubation with 5-aminolevulinic acid- 

 5-C^^ produced labeled porphobilinogen. Since the porpho- 

 bilinogen is presumably synthesized from 2 moles of 5-amino- 

 levulinic acid (Figure 5), its molar radioactivity should be twice 

 that of the 5-aminolevulinic acid used as the substrate. The 

 molar radioactivities of the substrate, 5-aminolevulinic acid, and 

 of the product, porphobilinogen, were found to be 242 X 10^ 



530 



