Mannosyl-oligosaccharide glucosidase

MOGS is a glycoside hydrolase enzyme, belonging to Family 63 as classified within the Carbohydrate-Active Enzyme database.{{Cite web|url=http://www.cazy.org/GH63.html|title=CAZy - GH63|website=www.cazy.org|access-date=2016-04-05}}

It catalyses exohydrolysis of the non-reducing terminal glucose residue in the mannosyl-oligosaccharide glycan Glc₃Man₉GlcNAc₂.

This reaction is the first trimming step in the N-glycosylation pathway. Prior to this, the glycan was co-translationally attached to a nascent protein by the oligosaccharyltransferase complex. MOGS removes the terminal glucose residue, leaving the glycoprotein linked to Glc₂Man₉GlcNAc₂, which can then serve as a substrate for glucosidase II.

File:MOGS substrate.png substrate for MOGS]]

MOGS is highly specific to the oligosaccharide in its biological substrate in the N-glycosylation pathway. Eukaryotic MOGS does not cleave simple substrates such as p-nitrophenyl glucose, and it also shows no activity to the α(1→3) linkage present at the terminus of Glc_1-2Man₉GlcNAc₂.{{cite journal | vauthors = Vijay IK, Shailubhai K, Dong-Yu B, Pratta MA, Saxena S | title = Studies on the biosynthesis and regulation of asparagine-linked glycoproteins in the lactating mammary gland | journal = Indian Journal of Biochemistry & Biophysics | volume = 25 | issue = 1-2 | pages = 127–32 | date = 1988-04-01 | pmid = 2846425 }}{{cite journal | vauthors = Dhanawansa R, Faridmoayer A, van der Merwe G, Li YX, Scaman CH | title = Overexpression, purification, and partial characterization of Saccharomyces cerevisiae processing α glucosidase I | journal = Glycobiology | volume = 12 | issue = 3 | pages = 229–34 | date = March 2002 | pmid = 11971867 | doi = 10.1016/0014-5793(86)80982-6 }}{{cite journal | vauthors = Shailubhai K, Saxena ES, Balapure AK, Vijay IK | title = Developmental regulation of glucosidase I, an enzyme involved in the processing of asparagine-linked glycoproteins in rat mammary gland | journal = The Journal of Biological Chemistry | volume = 265 | issue = 17 | pages = 9701–6 | date = June 1990 | pmid = 2190984 }} Furthermore, the minimum substrate is the glucotriose molecule (Glc-α(1→2)-Glc-α(1→3)-Glc), linked as in its native Glc₃Man₉GlcNAc₂ substrate. Kojibiose, the disaccharide Glc-α(1→2)-Glc, acts as a weak inhibitor on plant, animal, and yeast MOGS.{{cite journal | vauthors = Zeng YC, Elbein AD | title = Purification to homogeneity and properties of plant glucosidase I | journal = Archives of Biochemistry and Biophysics | volume = 355 | issue = 1 | pages = 26–34 | date = July 1998 | pmid = 9647663 | doi = 10.1006/abbi.1998.0717 }}{{cite journal | vauthors = Schweden J, Borgmann C, Legler G, Bause E | title = Characterization of calf liver glucosidase I and its inhibition by basic sugar analogs | journal = Archives of Biochemistry and Biophysics | volume = 248 | issue = 1 | pages = 335–40 | date = July 1986 | pmid = 2942110 | doi = 10.1016/0003-9861(86)90429-7 }}{{cite journal | vauthors = Ugalde RA, Staneloni RJ, Leloir LF | title = Microsomal glucosidases of rat liver. Partial purification and inhibition by disaccharides | journal = European Journal of Biochemistry | volume = 113 | issue = 1 | pages = 97–103 | date = December 1980 | pmid = 7460954 | doi=10.1111/j.1432-1033.1980.tb06144.x| doi-access = free | hdl = 11336/143170 | hdl-access = free }}

MOGS also acts to lesser extent on the corresponding glycolipids and glycopeptides.

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• {{MeshName|Mannosyl-oligosaccharide+glucosidase}}

{{Sugar hydrolases}}

{{Enzymes}}

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Category:EC 3.2.1