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{{Infobox enzyme
| Name = Dolichyl-P-Man:Man5GlcNAc2-PP-dolichol alpha-1,3-mannosyltransferase
| EC_number = 2.4.1.258
| CAS_number = 
| IUBMB_EC_number = 2/4/1/258
| GO_code = 
| image = 
| width = 
| caption =
}}
'''Dolichyl-P-Man:Man5GlcNAc2-PP-dolichol alpha-1,3-mannosyltransferase''' ({{EC number|2.4.1.258}}, ''Man5GlcNAc2-PP-Dol mannosyltransferase'', ''[[ALG3]]'', ''dolichyl-P-Man:Man(5)GlcNAc(2)-PP-dolichyl mannosyltransferase'', ''Not56-like protein'', ''Alg3 alpha-1,3-mannosyl transferase'', ''Dol-P-Man:Man5GlcNAc2-PP-Dol alpha-1,3-mannosyltransferase'') is an [[enzyme]] with system name ''dolichyl beta-D-mannosyl phosphate:D-Man-alpha-(1->2)-D-Man-alpha-(1->2)-D-Man-alpha-(1->3)-(D-Man-alpha-(1->6))-D-Man-beta-(1->4)-D-GlcNAc-beta-(1->4)-D-GlcNAc-diphosphodolichol alpha-1,3-mannosyltransferase''.<ref>{{cite journal | title = Biosynthesis of lipid-linked oligosaccharides in yeast: the ALG3 gene encodes the Dol-''P''-Man:Man<sub>5</sub>GlcNAc<sub>2</sub>-''PP''-Dol mannosyltransferase |author = Sharma, C.B., Knauer, R. and Lehle, L. |journal = Biol. Chem. |year = 2001 |volume = 382 |pages = 321–328 |pmid = 11308030}}</ref><ref>{{cite journal | title = The accumulation of Man(6)GlcNAc(2)-''PP''-dolichol in the ''Saccharomyces cerevisiae'' &Delta;''alg9'' mutant reveals a regulatory role for the Alg3p &alpha;1,3-Man middle-arm addition in downstream oligosaccharide-lipid and glycoprotein glycan processing |author = Cipollo, J.F. and Trimble, R.B. |journal = J. Biol. Chem. |year = 2000 |volume = 275 |pages = 4267–4277 |pmid = 10660594}}</ref> This enzyme [[catalysis|catalyses]] the following [[chemical reaction]]

: dolichyl beta-D-mannosyl phosphate + D-Man-alpha-(1->2)-D-Man-alpha-(1->2)-D-Man-alpha-(1->3)-[D-Man-alpha-(1->6)]-D-Man-beta-(1->4)-D-GlcNAc-beta-(1->4)-D-GlcNAc-diphosphodolichol <math>\rightleftharpoons</math> D-Man-alpha-(1->2)-D-Man-alpha-(1->2)-D-Man-alpha-(1->3)-[D-Man-alpha-(1->3)-D-Man-alpha-(1->6)]-D-Man-beta-(1->4)-D-GlcNAc-beta-(1->4)-D-GlcNAc-diphosphodolichol + dolichyl phosphate

The formation of N-glycosidic linkages of [[glycoprotein]]s involves the ordered assembly of the common Glc3Man9GlcNAc2 core-oligosaccharide on the lipid carrier dolichyl diphosphate.

== References ==
{{reflist}}

== External links ==
* {{MeshName|Dolichyl-P-Man:Man5GlcNAc2-PP-dolichol+alpha-1,3-mannosyltransferase}}

[[Category:EC 2.4.1]]