Phosphoryl- n-acetylglucosamine transfer to a lipid acceptor of liver microsomal preparations

Abstract

The preparation of [β- 32P]UDP- N-acetyl[1- 14C]glucosamine is described. This compound was used in reactions with microsomes of rabbit liver to investigate the pathway of glycoprotein synthesis in this system. The 32P and 14C were incorporated into a lipid component while only the 14C was found in the protein products. The lipid material was purified by ion exchange and two dimensional thin layer chromatography. In both of these systems the 32P and 14C migrated together. These results suggested that a single microsomal lipid component contained the β-phosphoryl and N-acetylglucosamine residues of the nucleotide-sugar and therefore UMP had to be the other product in the reaction. The “lipid-sugar” had properties similar to the “lipid intermediates” described for microorganisms. The results presented in this and previous papers suggested that this “lipid-sugar” may serve as an intermediate in glycoprotein synthesis.