Porphyrin Biosynthesis

Abstract

The enzymic system that catalyzes the total synthesis of protoporphyrin IX has been found in the Harderian gland of the rat. The presence of the enzyme δ‐aminolevulinic acid synthetase was demonstrated in mitochondria by the formation of [ 14 C]δ‐aminolevulinic acid. On incubation of homogenates of the Harderian glands with δ‐aminolevulinic acid and porphobilinogen, varying conditions such as temperature, time, aero‐or anaerobiosis and cofactor and substrate concentration, porphyrins with a carboxyl content ranging from 8–2 were formed. Thus, the presence of δ‐aminolevulinate dehydratase, porphobilinogenase, decarboxylase and coproporphyrinogenase systems were demonstrated.