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

Inferred from experiment

EC Number:

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

The direction shown, i.e. which substrates are on the left and right sides, 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:
Substrate Km (μM) Citations
Glc-β-EGF-like domain 34.0 [Ishimizu07]

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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