Study on the biosynthesis of dolichol in yeast: recognition of the prenyl chain length in polyprenol reduction

A Convenient Method for the Synthesis of (S)-Dolichol and (S)-Nordolichol

A procedure for the preparation of (S)-dolichol and (S)-nor-dolichol starting from the polyprenyl fraction extracted from Gingko Biloba integer or extracted leaves is described. Two chiral isoprenoid compounds in good yields and high degree of enantiomeric excess were obtained. The (S)-nordolichol appears to be a good chiral precursor for the preparation of 14C-labeled (S)-dolichol which is to be used in investigations aimed at gaining further information with respect to the role of dolichol in the function of living cells.

Genetic defects in dolichol metabolism

Congenital disorders of glycosylation (CDG) comprise a group of inborn errors of metabolism with abnormal glycosylation of proteins and lipids. Patients with defective protein N-glycosylation are identified in routine metabolic screening via analysis of serum transferrin glycosylation. Defects in the assembly of the dolichol linked Glc(3)Man(9)GlcNAc(2) glycan and its transfer to proteins lead to the (partial) absence of complete glycans on proteins. These defects are called CDG-I and are located in the endoplasmic reticulum (ER) or cytoplasm. Defects in the subsequent processing of protein bound glycans result in the presence of truncated glycans on proteins. These defects are called CDG-II and the enzymes involved are located mainly in the Golgi apparatus. In recent years, human defects have been identified in dolichol biosynthesis genes within the group of CDG-I patients. This has increased interest in dolichol metabolism, has resulted in specific recognizable clinical symptoms in CDG-I and has offered new mechanistic insights in dolichol biosynthesis. We here review its biosynthetic pathways, the clinical and biochemical phenotypes in dolichol-related CDG defects, up to the formation of dolichyl-P-mannose (Dol-P-Man), and discuss existing evidence of regulatory networks in dolichol metabolism to provide an outlook on therapeutic strategies.