FECH and nutritional disorder: The insertion of ferrous iron (Fe2+) into the porphyrin ring to form heme is catalyzed by the mitochondrial enzyme ferrochelatase, which shows reduced activity in the presence of lead (Ponka 1997).This reduction in ferrochelatase activity frees protoporphyrin to accept zinc, resulting in the formation of zinc protophorphyrin, which is characteristically increased in both lead poisoning and iron deficiency.