Identification ofSchizosaccharomyces pombePrenol as Dolichol-16,17

The identity of the prenol involved in N-linked glycosylation in the fission yeastSchizosaccharomyces pombewas unknown. In order to determine the identity of the prenol,S. pombecells were incubated with a metabolic precursor of prenol, tritiated mevalonolactone. The cells incorporated only a modest amount of label, about 1000 dpm per million cells, into base-stable lipid and only 1% of that radioactivity was incorporated into prenol. We found by normal phase silica HPLC and more directly by the lack of reactivity with MnO2that the labeled lipid was predominantly dolichol, not polyprenol. Reverse phase HPLC demonstrated that inS. pombedolichol ranged between 14 and 18 isoprene units with dolichol-16,17 being the most abundant prenol. This dolichol is of an intermediate length, between the dolichol ofS. cerevisiaeand that of mammalian cells.