Physiologic Role of Heme and Cytochrome P-450 in Hematopoietic Cells

Abstract

Heme (ferroprotoporphyrin IX) is a ubiquitous molecule that serves as the prosthetic group of a variety of important hemoproteins that are essential for hemopoietic processes. Heme is involved in oxygen transport as the prosthetic group of hemoglobin, in prostaglandin synthesis as the prosthetic group of cyclooxygenase, in the enzymatic decomposition of H2O2 as the prosthetic group of catalase and peroxidase, and in the inactivation of oxygen molecules, as the prosthetic group of mitochondrial and microsomal cytochrome P-450. The latter refers to a family of isozymes for which heme serves as the prosthetic group that oxidizes a wide variety of structurally unrelated compounds, inactivates leukotrienes (leukotriene B4), and metabolizes arachidonic acid (AA) to bioactive metabolites, some of which are involved in the signal transduction process for hematopoietic growth factors. However, the effect of heme on erythropoiesis appears to be distinct from its direct involvement as a prosthetic group.The expressi...