Dehydrodolichyl Diphosphate Synthase (DHDDS)

Dehydrodolichyl diphosphate (dedol-PP) synthase catalyzes cis-prenyl chain elongation to produce the polyprenyl backbone of dolichol, a glycosyl carrier lipid required for the biosynthesis of several classes of glycoproteins.The deduced 333-amino acid DHDDS protein contains all 5 regions conserved among cis-prenyl chain-elongating enzymes in several eukaryotic and prokaryotic species. DHDDS shares 41.8% homology with yeast dedol-PP synthase and 37.6% homology with E. coli UPS. Northern blot analysis detected high DHDDS expression in testis and kidney, with lower levels in heart, spleen, and thymus. Thin-layer chromatography detected synthesis of high levels of dolichols with major chain lengths of C90, C95, and C100, consistent with dolichols isolated from human tissues.