Direct estimation of dolichyl phosphate in rat liver by high pressure liquid chromatography.

A method involving reverse-phase high pressure liquid chromatography has been developed for determining the concentration of dolichyl phosphate (Dol-P) in tissues. Individual Dol-P homologs are resolved and amounts as small as 50 ng can be detected. Rat liver was found to contain 2.4 μg Dol-P/g wet weight, or ca. 4% of total liver dolichol. In contrast, rat liver microsomes contained 64 ng Dol-P/mg protein, which is about 40% of total microsomal dolichol. This enrichment in Dol-P is consistent with the role of microsomes as the major site of Dol-P-mediated, glycoprotein biosynthesis in liver