Dolichyl-phosphate beta-glucosyltransferase (ALG5)

Dolichyl-phosphate beta-glucosyltransferase (ALG5) is a transmembrane glycosyltransferase enzyme of the endoplasmic reticulum, essential to the biosynthetic pathway of dolichol-linked oligosaccharides used in N-linked glycosylation of proteins. ALG5 catalyzes the transfer of glucose from UDP-glucose to dolichyl-phosphate, forming dolichyl-phosphate-glucose (Dol-P-Glc), which is a crucial precursor for subsequent glycosylation steps by other ER-resident enzymes (ALG6, ALG8, ALG10). This chain of events forms mature glycan structures, necessary for proper folding, stability, and function of glycoproteins. ALG5 is localized on the cytosolic face of the ER membrane, and its activity is critical for substrate recognition and transfer in glycoprotein biosynthesis. Disease associations include atypical polycystic kidney disease when monoallelic loss-of-function variants are present, and potentially, congenital disorders of glycosylation if its function is impaired.

Other names

ALG5Asparagine-linked glycosylation protein 5 homologDolP-glucosyltransferasePKD7Dolichyl-phosphate glucosyltransferasebA421P11.2EC 2.4.1.117Asparagine-linked glycosylation 5 homolog (S. cerevisiae)Asparagine-linked glycosylation 5 homolog (yeast)

Not documented for drugs; the enzyme’s action is glucose transfer from UDP-glucose to dolichyl-phosphate, forming Dol-P-Glc