STUDY OF HEME BIOSYNTHETIC PATHWAY, ITS REGULATION BY ENZYMES, DISORDERS AND DISEASES DUE TO HEREDITARY GENE ALTERCATIONS

Sikander Ali*, Maira Javed and Aniqa Zia

ABSTRACT

Heme is synthesized naturally in almost all living organisms. There are various steps involved in the pathway of heme biosynthesis. Eight enzymes are involved in the making of heme. Liver and erythrocytes are two main sites for the heme synthesis as it forms cytochrome P450 that is important for the detoxification of xenobiotic compounds that are injected by individuals. Reticuloendothelial system at extracellular sites is involved in the removal and degradation of the old blood cells. Heme is released from hemoglobin and is degraded. Various factors are involved in regulating the expression of gene coding for the enzymes used in heme synthesis pathways. Heme oxygenase activity can be inhibited by other Porphyrins that contain certain metal ions other than iron (ferrous ion). Various disorders in heme biosynthesis can hinder the process; Porphyria is the main among them. Porphyria‟s are inherited and acquired disorders that are linked with the partially defective enzymatic activities of the heme biosynthesis pathway and increased level of precursors. Various types of Porphyria have been studied in this review. Here, a case report has also been included in which disease manifestation and symptoms have been illuminated. These attacks could be controlled by proper medication and hospitalization.

Keywords: Heme, Metalloporphyrins, ALAS1, ALAS2, Feedback control, Protoporphyrin, Reticuloendothelial system, and AIP.