Heme is central to functions of many biologically important enzymes (hemoproteins). It is an
assembly of four porphyrin rings joined through methylene bridges with a central Fe (II). Heme is present
in all cells, and its synthesis and degradation balance its amount in the cell. The deregulations of
heme networks and incorporation in hemoproteins lead to pathogenic state. This article addresses the
detailed structure, biosynthesis, degradation, and transportation associated afflictions to heme. The
article is followed by its roles in various diseased conditions where it is produced mainly as the cause of
increased hemolysis. It manifests the symptoms in diseases as it is a pro-oxidant, pro-inflammatory and
pro-hemolytic agent. We have also discussed the genetic defects that tampered with the biosynthesis,
degradation, and transportation of heme. In addition, a brief about the largest hemoprotein group of enzymes-
Cytochrome P450 (CYP450) has been discussed with its roles in drug metabolism.
Synthesis and degradation of poly(A) in permeable cells of Escherichia coli