640 



•XIII. HEMOGLOBIN AND PORPHYRIN SYNTHESIS 



Alternatively the synthesis might take place by condensation of 

 glutamic acid with ketoglutaric acid, by intramolecular condensation 

 of a dipeptide of /3-hydroxyglutamic acid and glutamic acid, or by 

 oxidation of a dipeptide of glutamic acid alone (Fig. 6). A dipeptide 



CO,H 



CO2H 



CO2H CH2 CO2H CH. 



CH, CH2 CH. CH2 



CH(OH) CHNHo 



HO.C N 



H. 



AC P 



H 



Figure 6 



of hydroxyglutamic acid with proline has been isolated from the liver 

 by West and Howe (3039). Finally glycine may be condensed with the 

 semialdehyde of succinic acid (Fig. 7). 



CO2H 



CO2H CH2 



I I 



CH2 CH2 _ 



CH2 CHO 



I i 



CHO CH> — CO2H 



\^ ■ 



H2 



AC P 



^N'^co2n 



H 



Figure 7 



