Bilirubin Inhibition of Heme Biosynthesis

Abstract

The conversion of protoporphyrin and iron to heme is catalyzed by a soluble enzyme prepared from rat liver. This reaction is inhibited by bilirubin, and initial kinetic studies suggest that the inhibition is due in part to a competition between protoporphyrin and the bile pigment. Implications of this finding in hyperbilirubinemia are mentioned.