Which is an inhibitor of ferrochelatase ?

Ans. is 'a' i.e., Lead o Ferrochelatase, also called heme synthase, catalyses the last reaction in heme synthesis.o Heme synthesis takes place in all cells, but occurs to greatest extent in bone marrow and liver. The first step in the synthesis of heme is the condensation of glycine and succinyl Co-A to form d-aminolevulinic acid (d-ALA), which occurs in mitochondria. This reaction is catalyzed by d-ALA synthase which requires pyridoxal phosphate (PLP) as cofactor. This is the rate limiting step in heme synthesis.o Lead inhibits ALA dehydratase. Therefore, lead poisoning causes inhibition of heme synthesis and excessive amount of d-ALA is excreted in urine. Lead can also inhibit ferrochelatase (heme synthase).