ALG3 transfers Man to N-glycan precursor (GlcNAc)2 (Man)5 (PP-Dol)1

Stable Identifier
Reaction [transition]
Homo sapiens
Addition of the sixth mannose to the N-glycan precursor by ALG3
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The sixth mannose is added to the N-glycan precursor. This reaction occurs in the ER lumen and uses a different mannose donor (dolichyl-phosphate-mannose) than the previous steps. It has been proposed that ALG3, along with all the mannosyl- and glucosyltransferases in the N-glycan biosynthesis pathway that use dolichyl-phosphate-mannose or dolichyl-phosphate-glucose as donor, derive from duplications of a common ancestral enzyme (Oriol et al. 2002). Defects in ALG3 are associated with Congenital Disorder of Glycosylation 1D (CDG1D) (Sun et al. 2005).

Literature References
PubMed ID Title Journal Year
12200473 Common origin and evolution of glycosyltransferases using Dol-P-monosaccharides as donor substrate

Mollicone, R, Codogno, P, Oriol, R, Chantret, I, Martinez-Duncker, I

Mol Biol Evol 2002
15840742 Congenital disorder of glycosylation id presenting with hyperinsulinemic hypoglycemia and islet cell hyperplasia

Cohen, J, Chung, WK, Freeze, HH, Wang, C, Eklund, EA, Sun, L

J Clin Endocrinol Metab 2005
Catalyst Activity

alpha-1,3-mannosyltransferase activity of ALG3 [endoplasmic reticulum membrane]

This event is regulated
Orthologous Events
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