EC - Glucuronosyl-galactosyl-proteoglycan 4-α-N-acetylglucosaminyltransferase

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IntEnz Enzyme Nomenclature


Accepted name:
glucuronosyl-galactosyl-proteoglycan 4-α-N-acetylglucosaminyltransferase
Other names:
α-N-acetylglucosaminyltransferase I
glucuronosylgalactosyl-proteoglycan 4-α-N-acetylglucosaminyltransferase
UDP-N-acetyl-D-glucosamine:β-D-glucuronosyl-(1→3)-β-D-galactosyl-(1→3)-β-D-galactosyl-(1→4)-β-D-xylosyl-proteoglycan 4IV-α-N-acetyl-D-glucosaminyltransferase
glucuronyl-galactosyl-proteoglycan 4-α-N-acetylglucosaminyltransferase
Systematic name:
UDP-N-acetyl-α-D-glucosamine:[protein]-3-O-(β-D-GlcA-(1→3)-β-D-Gal-(1→3)-β-D-Gal-(1→4)-β-D-Xyl)-L-serine 4IV-α-N-acetyl-D-glucosaminyltransferase (configuration-retaining)



Enzyme involved in the initiation of heparin and heparan sulfate synthesis, transferring GlcNAc to the (GlcA-Gal-Gal-Xyl-)Ser core. Apparently products of both the human EXTL2 and EXTL3 genes can catalyse this reaction. In Caenorhabditis elegans, the product of the rib-2 gene displays this activity as well as that of EC, glucuronosyl-N-acetylglucosaminyl-proteoglycan 4-α-N-acetylglucosaminyltransferase. For explanation of the use of a superscript in the systematic name, see 2-Carb-37.2.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0001888
CAS Registry Number: 179241-74-8


  1. Kitagawa, H., Shimakawa, H. and Sugahara, K.
    The tumor suppressor EXT-like gene EXTL2 encodes an α1,4-N-acetylhexosaminyltransferase that transfers N-acetylgalactosamine and N-acetylglucosamine to the common glycosaminoglycan-protein linkage region. The key enzyme for the chain initiation of heparan sulfate.
    J. Biol. Chem. 274: 13933-13937 (1999). [PMID: 10318803]
  2. Kitagawa, H., Egusa, N., Tamura, J.I., Kusche-Gullberg, M., Lindahl, U. and Sugahara, K.
    rib-2, a Caenorhabditis elegans homolog of the human tumor suppressor EXT genes encodes a novel α1,4-N-acetylglucosaminyltransferase involved in the biosynthetic initiation and elongation of heparan sulfate.
    J. Biol. Chem. 276: 4834-4838 (2001). [PMID: 11121397]

[EC created 2002, modified 2016]