The transfer of galactose from UDP-galactose to endogenous lipid acceptors in liver microsomes.

When the microsomal fraction of beef liver is incubated with UDP-[14-C]-galactose in the presence of an inhibitor of nucleotide pyrophosphatase, there is an incorporation of the [14-C]galactose into glycoprotein and into two lipid components, one soluble in chloroform and the other in chloroform/methanol/water (1:1:0.3). Chromatography of the chloroform fraction on DEAE-cellulose or Kieselguhr G gives a single peak with behavior identical to that of dolichol phosphate mannose. Hydrolysis of the chloroform fraction released free galactose. It seems, therefore, that galactose, like glucose, mannose, and N-acetylglucosamine, can be transferred from its respective sugar nucleotide to glycoprotein via dolichol intermediates.