Molecular insights into beta-galactoside alpha2,6-sialyltransferase secretion in vivo

Glycobiology. 2009 May;19(5):479-87. doi: 10.1093/glycob/cwp003. Epub 2009 Jan 15.


Beta-galactoside alpha2,6-sialyltransferase (ST6Gal I), which is highly expressed in the liver, is mainly cleaved by Alzheimer's beta-site amyloid precursor protein-cleaving enzyme 1 (BACE1) and secreted into the serum. During our studies to elucidate the molecular mechanism underlying the cleavage and secretion of ST6Gal I, we hypothesized that plasma ST6Gal I may represent a sensitive biomarker for hepatopathological situations. In the present study, we used recently developed sandwich ELISA systems that specifically detect the soluble cleaved form of ST6Gal I in plasma. We found that the level of plasma ST6Gal I was increased in two different types of liver injury models. In zone 1 hepatocyte-injured rats, the level of plasma ST6Gal I was increased together with acute phase reactions. Meanwhile, in zone 3 hepatocyte-injured rats, ST6Gal I secretion was most likely triggered by oxidative stress. Taken together, we propose two possible mechanisms for the upregulation of plasma ST6Gal I in hepatopathological situations: one accompanied by acute phase reactions to increase hepatic ST6Gal I expression and the other triggered by oxidative stress in the liver. We also found that the serum level of ST6Gal I in hepatitis C patients was correlated with the activity of hepatic inflammation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Amyloid Precursor Protein Secretases / metabolism*
  • Animals
  • Aspartic Acid Endopeptidases / metabolism*
  • Bromobenzenes / pharmacology
  • Cells, Cultured
  • Disease Models, Animal
  • Hepatitis C / metabolism
  • Hepatocytes / enzymology*
  • Humans
  • Hydrogen Peroxide / pharmacology
  • Liver / drug effects
  • Liver / enzymology*
  • Male
  • Molecular Sequence Data
  • Oxidative Stress / physiology*
  • Propanols / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Rats, Wistar
  • Sialyltransferases / metabolism
  • Sialyltransferases / physiology*
  • beta-D-Galactoside alpha 2-6-Sialyltransferase


  • Bromobenzenes
  • Propanols
  • allyl alcohol
  • Hydrogen Peroxide
  • bromobenzene
  • Sialyltransferases
  • Amyloid Precursor Protein Secretases
  • Aspartic Acid Endopeptidases
  • Bace1 protein, rat
  • beta-D-Galactoside alpha 2-6-Sialyltransferase