Bile pigment formation in vitro from haematin and haem derivatives

Abstract

Spectroscopic studies were made on the in vitro conversion of hematin and some other heme derivatives into bile pigments through the action of ascorbic acid and oxygen. The. conversion of hematin into bile pigments is associated with increased optical density in the range 630-700 m[mu] and evidence was obtained for the presence of verdohematin and cholehematin in the reaction products. The yield of bile pigment derived from metmyoglobin was approx. 11 times that from oxyhemoglobin under similar exptl. conditions. Cholemyoglobin was observed spectroscopically. Horse-radish peroxidase was converted into bile pigment in 2.9% yield of its heme content, and the bile pigment hematin content of horse-liver catalase was increased from 27 to 39%. With the exception of cytochrome c, all heme derivatives in the series suffered, in varying degree, oxidative breakdown to bile pigment in the presence of ascorbic acid and O2.