title: Reaction of optically active S- and R-forms of dolichyl phosphates with activated sugars.
abstract: Chemical synthesis was used to produce optically active isomers of dolichol (S- and R-forms) with 18 and 19 isoprene residues. The phosphorylated polyprene was studied in rat liver microsomal GDP-mannosyl and UDP-N-acetylglucosaminyl transferase systems. The two dolichol-P forms in both transferase systems gave Vmax values which for the S-form exceeded 4-6 times what was obtained with the R-form. The Km values were also higher for the S-form. The hepatocyte appears to contain a large excess of dolichyl-P, by 100 times exceeding that of the Km values. For this reason the S-form of dolichyl-P seems to be one of the requirements for the normal establishment of the N-glycosidically linked oligosaccharide chain.
mesh_terms: D000818:Animals; D004288:Dolichol Phosphates / Q000138:chemical synthesis / Q000378:metabolism*; D006602:Hexosyltransferases / Q000378:metabolism*; D007700:Kinetics; D008862:Microsomes, Liver / Q000378:metabolism*; D011106:Polyisoprenyl Phosphates / Q000378:metabolism*; D051381:Rats; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D013552:Swine
chemical_list: D004288:Dolichol Phosphates; D011106:Polyisoprenyl Phosphates; D006602:Hexosyltransferases