View source for Acetylgalactosaminyl-O-glycosyl-glycoprotein b-1,6-N-acetylglucosaminyltransferase

{{Infobox enzyme
| Name = Glucuronyl-galactosyl-proteoglycan 4-alpha-N-acetylglucosaminyltransferase
| EC_number = 2.4.1.223
| CAS_number = 179241-74-8
| IUBMB_EC_number = 2/4/1/223
| GO_code = 
| image = 
| width = 
| caption =
}}
'''Glucuronyl-galactosyl-proteoglycan 4-alpha-N-acetylglucosaminyltransferase''' ({{EC number|2.4.1.223}}, ''alpha-N-acetylglucosaminyltransferase I'', ''alpha1,4-N-acetylglucosaminyltransferase'', ''glucuronosylgalactosyl-proteoglycan 4-alpha-N-acetylglucosaminyltransferase'') is an [[enzyme]] with system name ''UDP-N-acetyl-D-glucosamine:beta-D-glucuronosyl-(1->3)-beta-D-galactosyl-(1->3)-beta-D-galactosyl-(1->4)-beta-D-xylosyl-proteoglycan 4IV-alpha-N-acetyl-D-glucosaminyltransferase''.<ref>{{cite journal | title = The tumor suppressor EXT-like gene EXTL2 encodes an &alpha;1,4-''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 |author = Kitagawa, H., Shimakawa, H. and Sugahara, K. |journal = J. Biol. Chem. |year = 1999 |volume = 274 |pages = 13933–13937 |pmid = 10318803 |doi=10.1074/jbc.274.20.13933}}</ref><ref>{{cite journal | title = ''rib-2'', a ''Caenorhabditis elegans'' homolog of the human tumor suppressor ''EXT'' genes encodes a novel &alpha;1,4-''N''-acetylglucosaminyltransferase involved in the biosynthetic initiation and elongation of heparan sulfate |author = Kitagawa, H., Egusa, N., Tamura, J.I., Kusche-Gullberg, M., Lindahl, U. and Sugahara, K. |journal = J. Biol. Chem. |year = 2001 |volume = 276 |pages = 4834–4838 |pmid = 11121397 |doi=10.1074/jbc.C000835200 |issue=7}}</ref> This enzyme [[catalysis|catalyses]] the following [[chemical reaction]]

: [[UDP-N-acetyl-D-glucosamine]] + beta-D-glucuronosyl-(1->3)-beta-D-galactosyl-(1->3)-beta-D-galactosyl-(1->4)-beta-D-xylosyl-proteoglycan <math>\rightleftharpoons</math> UDP + alpha-N-acetyl-D-glucosaminyl-(1->4)-beta-D-glucuronosyl-(1->3)-beta-D-galactosyl-(1->3)-beta-D-galactosyl-(1->4)-beta-D-xylosyl-proteoglycan

This enzyme is involved in the initiation of [[heparin]] and [[heparan sulfate]] synthesis.

== References ==
{{reflist}}

== External links ==
* {{MeshName|Glucuronyl-galactosyl-proteoglycan+4-alpha-N-acetylglucosaminyltransferase}}

[[Category:EC 2.4.1]]