Bilirubin binding to myelin basic protein, histones and its inhibition in vitro of cerebellar protein synthesis

Abstract

SummaryThe binding of unconjugated bilirubin to bovine CNS myelin basic protein and to lysine and arginine rich histones has been demonstrated by means of difference spectroscopy and circular dichroism spectroscopy. This is the first demonstration of a brain specific protein that can bind bilirubin and provides a mechanism for bilirubin retention in brain as well as a mechanism for interfering with the normal acidic lipid-basic protein binding interaction. The inhibition of protein synthesis in cerebellar homogenates by bilirubin has also been demonstrated. The inhibition is about 50 per cent in the presence of 100 [mu]M bilirubin and 85 per cent in the presence of 700 [mu]M bilirubin, These results require that the current mechanisms for bilirubin neurotoxicity and cytotoxicity be expanded to include the present findings.