Biosynthesis of glycoconjugates in mitochondrial outer membranes. Preliminary characterization of the oligosaccharide moiety of a N-glycoprotein
Levrat, C.; Ardail, D.; Louisot, P.
Biochemistry International 20(1): 1-11
1990
ISSN/ISBN: 0158-5231 PMID: 2328016 Document Number: 365314
Outer mitochondrial membranes synthesize a N-glycoprotein by a direct incorporation of sugars from their nucleotide-donors into an endogenous protein acceptor. To characterize the oligosaccharide moiety of this N-glycoprotein, we sequentially incorporated [14C]-sugars into the protein acceptor. After pronase digest, the released [14C]-glycopeptides were fractionated on a QAE-Sephadex column which gave rise to 9% of neutral glycopeptides and 91% of charged glycopeptides. These latter were identified as bearing phosphate residues in the form of monoester (28%) and acid-stable diester (63%). The oligosaccharide moiety of this mitochondrial glycoprotein has been characterized as incomplete biantennary complex-type chains.