MetaCyc Enzyme: UDP-D-xylose:β-D-glucoside α-1,3-D-xylosyltransferase

Species: Bos taurus

A unique O-glycan structure, the trisaccharide Xylα1-3Xylα1-3Glcβ1-O-Ser, is found on the consensus sequence C-X-S-X-P-C (X stands for any amino acid) in epidermal growth factor (EGF)-like domains of plasma proteins such as clotting factor VII and clotting factor IX (see Xyl-α(1-3)-Xyl-α(1-3)-Glc-β-EGF-like domain) [Omichi97].

One of the enzymes involved in catalyzing the biosynthesis of this trisaccharide, UDP-D-xylose:β-D-glucoside α-1,3-D-xylosyltransferase, has been purified from the microsomal fraction of bovine liver [Ishimizu07]. The best acceptor substrate of those tested was the EGF-like domain of bovine factor IX carrying beta-glucoside at Ser53.

Upon purification a second active peak wht molecular weight of 124 kDa was also observed. This peak was thought to represent a dimer of the protein [Ishimizu07].

Molecular Weight of Polypeptide: 52.0 kD (experimental) [Ishimizu07 ]

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Created 24-Feb-2010 by Caspi R , SRI International

Enzymatic reaction of: UDP-D-xylose:β-D-glucoside α-1,3-D-xylosyltransferase

EC Number:

UDP-α-D-xylose + Glc-β-EGF-like domain <=> UDP + Xyl-α(1-3)-Glc-β-EGF-like domain

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

Reversibility of this reaction is unspecified.

Cofactors or Prosthetic Groups: Mn2+ [Ishimizu07]

Inhibitors (Unknown Mechanism): Co2+ [Ishimizu07] , Cu2+ [Ishimizu07] , Fe2+ [Ishimizu07] , Ni2+ [Ishimizu07]

Kinetic Parameters:

Km (μM)
Glc-β-EGF-like domain

pH(opt): 7 [Ishimizu07]


Ishimizu07: Ishimizu T, Sano K, Uchida T, Teshima H, Omichi K, Hojo H, Nakahara Y, Hase S (2007). "Purification and substrate specificity of UDP-D-xylose:beta-D-glucoside alpha-1,3-D-xylosyltransferase involved in the biosynthesis of the Xyl alpha1-3Xyl alpha1-3Glc beta1-O-Ser on epidermal growth factor-like domains." J Biochem 141(4);593-600. PMID: 17317689

Omichi97: Omichi K, Aoki K, Minamida S, Hase S (1997). "Presence of UDP-D-xylose: beta-D-glucoside alpha-1,3-D-xylosyltransferase involved in the biosynthesis of the Xyl alpha 1-3Glc beta-Ser structure of glycoproteins in the human hepatoma cell line HepG2." Eur J Biochem 245(1);143-6. PMID: 9128735

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
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