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Difference between revisions of "Glycoside Hydrolase Family 99"
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== Substrate specificities == | == Substrate specificities == | ||
| − | + | [[Glycoside hydrolases]] of family GH99 are [[endo]]-acting α-mannosidases that cleave glucose-substituted mannose within immature N-linked glycans of the general formula Glc<sub>1-3</sub>Man<sub>9</sub>GlcNAc<sub>2</sub>, with maximal activity on the monoglucosylated forms <cite>1</cite>. This family was originally created from mammalian enzyme, cloned by Spiro and co-workers <cite>2</cite>. Mammalian GH99 enzymes are localized to the Golgi apparatus <cite>3</cite> and appear to play a role in the rescue of glucosylated N-linked glycans that have evaded the action of the endoplasmic reticulum ''exo''-glucosidases I and II <cite>4</cite>. Mammalian [[endo]]-α-mannosidases has increased activity on glucosylated N-linked glycans that have been trimmed in the non-glucose-substituted branches <cite>2</cite>. There is evidence that mammalian [[endo]]-α-mannosidases act on dolichol-bound N-glycan precursors <cite>6</cite>, as well as free oligosaccharides released from N-glycoproteins and which undergo retrograde transport through the secretory pathway <cite>5</cite>. | |
== Kinetics and Mechanism == | == Kinetics and Mechanism == | ||
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== References == | == References == | ||
<biblio> | <biblio> | ||
| − | # | + | #1 pmid=12770767 |
| − | # | + | |
| + | #2 pmid=9361017 | ||
| + | |||
| + | #3 pmid=11102520 | ||
| + | |||
| + | #4 pmid=3087421 | ||
| + | |||
| + | #5 pmid=21585340 | ||
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</biblio> | </biblio> | ||
[[Category:Glycoside Hydrolase Families|GH099]] | [[Category:Glycoside Hydrolase Families|GH099]] | ||
Revision as of 21:18, 2 January 2012
This page is currently under construction. This means that the Responsible Curator has deemed that the page's content is not quite up to CAZypedia's standards for full public consumption. All information should be considered to be under revision and may be subject to major changes.
- Author: ^^^Spencer Williams^^^
- Responsible Curator: ^^^Gideon Davies^^^
| Glycoside Hydrolase Family GH99 | |
| Clan | GH-x |
| Mechanism | retaining/inverting |
| Active site residues | known/not known |
| CAZy DB link | |
| http://www.cazy.org/GH99.html | |
Substrate specificities
Glycoside hydrolases of family GH99 are endo-acting α-mannosidases that cleave glucose-substituted mannose within immature N-linked glycans of the general formula Glc1-3Man9GlcNAc2, with maximal activity on the monoglucosylated forms [1]. This family was originally created from mammalian enzyme, cloned by Spiro and co-workers [2]. Mammalian GH99 enzymes are localized to the Golgi apparatus [3] and appear to play a role in the rescue of glucosylated N-linked glycans that have evaded the action of the endoplasmic reticulum exo-glucosidases I and II [4]. Mammalian endo-α-mannosidases has increased activity on glucosylated N-linked glycans that have been trimmed in the non-glucose-substituted branches [2]. There is evidence that mammalian endo-α-mannosidases act on dolichol-bound N-glycan precursors [5], as well as free oligosaccharides released from N-glycoproteins and which undergo retrograde transport through the secretory pathway [6].
Kinetics and Mechanism
Content is to be added here.
Catalytic Residues
Content is to be added here.
Three-dimensional structures
Content is to be added here.
Family Firsts
- First stereochemistry determination
- Content is to be added here.
- First catalytic nucleophile identification
- Content is to be added here.
- First general acid/base residue identification
- Content is to be added here.
- First 3-D structure
- Content is to be added here.
References
- Roth J, Ziak M, and Zuber C. (2003). The role of glucosidase II and endomannosidase in glucose trimming of asparagine-linked oligosaccharides. Biochimie. 2003;85(3-4):287-94. DOI:10.1016/s0300-9084(03)00049-x |
- Spiro MJ, Bhoyroo VD, and Spiro RG. (1997). Molecular cloning and expression of rat liver endo-alpha-mannosidase, an N-linked oligosaccharide processing enzyme. J Biol Chem. 1997;272(46):29356-63. DOI:10.1074/jbc.272.46.29356 |
- Zuber C, Spiro MJ, Guhl B, Spiro RG, and Roth J. (2000). Golgi apparatus immunolocalization of endomannosidase suggests post-endoplasmic reticulum glucose trimming: implications for quality control. Mol Biol Cell. 2000;11(12):4227-40. DOI:10.1091/mbc.11.12.4227 |
- Dale MP, Kopfler WP, Chait I, and Byers LD. (1986). Beta-glucosidase: substrate, solvent, and viscosity variation as probes of the rate-limiting steps. Biochemistry. 1986;25(9):2522-9. DOI:10.1021/bi00357a036 |
- Kukushkin NV, Alonzi DS, Dwek RA, and Butters TD. (2011). Demonstration that endoplasmic reticulum-associated degradation of glycoproteins can occur downstream of processing by endomannosidase. Biochem J. 2011;438(1):133-42. DOI:10.1042/BJ20110186 |