EC Number   |
General Information |
Reference |
|---|
   2.4.99.18 | physiological function |
asparagine-linked glycosylation (N-linked glycosylation) is an essential and highly conserved post-translational protein modification. This modification is essential for specific molecular recognition, protein folding, sorting in the endoplasmic reticulum, cell-cell communication, and stability |
-, 758885 |
| 2.4.99.18 | physiological function |
asparagine-linked glycosylation (N-linked glycosylation) is an essential and highly conserved post-translational protein modification. This modification is essential for specific molecular recognition, protein folding, sorting in the endoplasmic reticulum, cell-cell communication, and stability. In humans and other mammals, the oligosaccharyltransferase (OST) complex has diverged into two distinct isoforms known as OST-A and OST-B that perform distinctly different roles in N-linked glycosylation of proteins. OST-A is connected directly to the translocation channel called Sec61 in the ER membrane and scans the newly synthesized unfolded polypeptide chain emerging from the ribosome for glycosylation sites. Therefore, OST-A is responsible for the majority of N-linked glycosylation in mammals. OST-B seems to act in a proofreading role to catch glycosylation sites that OST-A misses for partially folded proteins or proteins that contain disulfide bonds |
758885 |
| 2.4.99.18 | physiological function |
asparagine-linked glycosylation is a common and vital co- and post-translocational modification of diverse secretory and membrane proteins in eukaryotes that is catalyzed by the multiprotein complex oligosaccharyltransferase. Isozymes Ost3p or Ost6p possess different protein substrate specificities at the level of individual glycosylation sites, model of Ost3/6p function in which they transiently bind stretches of nascent polypeptide substrate to inhibit protein folding, thereby increasing glycosylation efficiency at nearby asparagine residues |
720994 |
| 2.4.99.18 | physiological function |
asparagine-linked glycosylation is a common and vital co- and post-translocational modification of diverse secretory and membrane proteins in eukaryotes that is catalyzed by the multiprotein complex oligosaccharyltransferase. Ispzymes Ost3p or Ost6p possess different protein substrate specificities at the level of individual glycosylation sites. Ost6p, which has a peptide-binding groove with a strongly hydrophobic base lined by neutral and basic residues, binds peptides enriched in hydrophobic and acidic amino acids. Model of Ost3/6p function in which they transiently bind stretches of nascent polypeptide substrate to inhibit protein folding, thereby increasing glycosylation efficiency at nearby asparagine residues |
720994 |
| 2.4.99.18 | more |
Canine OST isoforms harboring the different Stt3 proteins differ in catalytic activity and substrate selectivity. OST complexes with the Stt3-B isoform are more active reaching 8 to 12fold higher Vmax values for glycopeptide formation than complexes containing Stt3-A. The increased catalytic activity for Stt3-B complexes coincides with a reduced selectivity with respect to the oligosaccharide donor substrate. OST complexes with Stt3-B accept the dolichol-pyrophosphate-activated Glc3Man9GlcNAc2 and Man9GlcNAc2 substrates with roughly the same specificity, whereas OST complexes with Stt3-A are more selective, as reflected by increased Km values forMan9GlcNAc2 relative to Glc3Man9GlcNAc2. Stt3-A and Stt3-B also differ in their acceptor substrate selectivity |
720164 |
| 2.4.99.18 | malfunction |
congenital disorders of glycosylation (CDG) have severe effects in humans, complete loss is lethal for eukaryots |
707520 |
| 2.4.99.18 | malfunction |
defects in N-linked glycosylation results in a class of inherited diseases known as congenital disorders of glycosylation |
758885 |
| 2.4.99.18 | physiological function |
free monomeric enzyme with broad specificity for nonglucosylated lipid-linked mannose-oligosaccharides typical for protists, incorporated in yeast enzyme complex it also transfers the common eukaryotic Glc3Man9GlcNAc2-PP-Dol donor |
708611 |
| 2.4.99.18 | metabolism |
in the central reaction of the N-linked glycosylation pathway, one of the most abundant modifications of proteins in eukaryotes, oligosaccharyltransferase, a multimeric complex located at the membrane of the endoplasmic reticulum, transfers a preassembled oligosaccharide to selected asparagine residues within the consensus sequence asparagine-X-serine/threonine |
720164 |
| 2.4.99.18 | metabolism |
in the central reaction of the N-linked glycosylation pathway, one of the most abundant modifications of proteins in eukaryoties, oligosaccharyltransferase, a multimeric complex located at the membrane of the endoplasmic reticulum, transfers a preassembled oligosaccharide to selected asparagine residues within the consensus sequence asparagine-X-serine/threonine |
720164 |
