Synthesis of dolichol derivatives in trypanosomatids. Characterization of enzymatic patterns.

摘要: We have previously described that in certain parasitic protozoa, namely the trypanosomatids, dolichol-P-P-linked oligosaccharides synthesized vivo and transferred to protein are devoid of glucose residues contain 6, 7, or 9 mannose units depending on species. now conducted a cell-free characterization enzymatic patterns responsible for these phenotypes. Microsomes from Trypanosoma cruzi, Crithidia fasciculata, Leishmania enriettii, Blastocrithidia culicis were found synthesize dolichol-P-[14C]Man but not dolichol-P-[14C]Glc when incubated with rat liver dolichol-P GDP-[14C]Man UDP-[14C]Glc, thus providing an explanation absence glucosylated dolichol-P-P derivatives. Formation dolichol-P-P-oligosaccharides was assayed incubation mixtures containing dolichol-P, GDP-[14C]Man, microsomes, unlabeled Man5-8GlcNAc2-P-P-dolichol bovine liver. Membranes species synthesizing Man6GlcNAc2 Man7GlcNAc2 same compounds higher homologues assay. Species forming Man9GlcNAc2-P-P-dolichol lipid-linked Man7GlcNAc2, Man8GlcNAc2, Man9GlcNAc2 vitro. It is concluded there at least three probably four different dolichol-P-Man-dependent activities involved synthesis microorganisms compound all mannosyltransferases addition missing only enzyme homologue than oligosaccharide occurring by single unit.