Biochemistry, molecular biology, and genetics of the oligosaccharyltransferase

UMMS Affiliation

Department of Biochemistry and Molecular Biology

Publication Date


Document Type



Animals; Carbohydrate Sequence; Forecasting; Glycosylation; *Hexosyltransferases; Humans; *Membrane Proteins; Molecular Sequence Data; Phenotype; Saccharomyces cerevisiae; Transferases


Life Sciences | Medicine and Health Sciences


Asparagine-linked glycosylation is a highly conserved protein modification reaction that occurs in all eukaryotes. The initial stage in the biosynthesis of N-linked glycoproteins, catalyzed by the enzyme oligosaccharyltransferase (OST), involves the transfer of a preassembled high-mannose oligosaccharide from a dolichol-linked oligosaccharide donor onto asparagine acceptor sites in nascent proteins in the lumen of the rough endoplasmic reticulum. Biochemical, molecular biological, and genetic studies conducted during the past 5 years have resulted in an explosive growth in our knowledge concerning the OST. Although the basic biochemical properties of the enzyme were determined more than a decade ago using intact microsomal membranes, recent studies provide novel insight into the catalytic mechanism of the enzyme. The OST was recently purified as a large heteroligomeric membrane protein complex; the sequences of many of the subunits have been determined from both fungal and vertebrate sources. Consistent with the evolutionary conservation of N-linked glycosylation, protein sequence comparisons reveal significant homologies between vertebrate, invertebrate, plant, and fungal OST subunits. Yeast molecular genetic methods have been instrumental in the functional characterization of the OST subunits, and have proven to be powerful tools for the identification of novel gene products that influence oligosaccharide transfer in vivo.

DOI of Published Version



FASEB J. 1996 Jun;10(8):849-58.

Journal/Book/Conference Title

The FASEB journal : official publication of the Federation of American Societies for Experimental Biology glycotransferase)

Related Resources

Link to Article in PubMed

PubMed ID