Subcellular distribution of dolichol phosphate

Abstract

A crude preparation of liver microsomes was shown to catalyze the transfer of glucose from UDP-Glc to Dol-P** to form Dol-P-Glc [ 1 ] . ~ub~quently it was observed that microsomes also transferred the glucose from Dol-P-Glc to an endogenous acceptor. This latter compound is probably another dolichol derivative containing about 20 monosaccharide units bound to dolichol through a phosphate or pyrophosphate bridge [2,3]. The abbreviation Glc-acceptor will be used for this dolichol derivative until the details of its structure are known with certainty, Liver microsomes also catalyze the transfer of mannose to Dol-P from GDP-mannose and of N-acetyl ~ucos~ine from UDP-GlcNAc to form what seems to be dolichol monophosphate mannose and dolichol monophosphate N-aeetyl glucosamine [4, S] . It is possible that the dolichol derivatives are intermediates involved in the synthesis of the sugar portions of the various glycoproteins and glycolipids occurring in smooth microsomes, the Golgi system and other cellular membranes. It is therefore necessary to establish the subcellular loc~ization of these derivatives.