Hemopexin

Abstract

ACUTE, hemolytic episodes have long been recognized as a frequent cause of renal failure.^{1 , 2} Nevertheless, although most details of the biosynthetic pathway for heme and hemoglobin^{3 4 5 6 7} are known, the mechanism of hemoglobin degradation^{8 9 10 11 12} remains largely unexplored.During intravascular hemolysis, hemoglobin is released into the plasma, and both hemoglobin and heme may be detected in the circulation.¹³ Plasma contains three hemoglobin-binding or heme-binding proteins: haptoglobin, albumin and hemopexin. Haptoglobin¹⁴ binds hemoglobin but not heme; albumin¹⁵ and hemopexin¹³ bind the free heme† but not hemoglobin.The serums of patients who have suffered intravascular hemolysis invariably lack haptoglobin^{16 , 17} because the hemoglobin-haptoglobin complex is . . .