Synthesis of gamma-carboxylated polypeptides by alpha-cells of the pancreatic islets

Leisa Stenberg, Elise Nilsson, Otto Ljungberg, Johan Stenflo, Mark A. Brown

Research output: Contribution to journalArticlepeer-review

17 Citations (SciVal)

Abstract

gamma -Carboxylated proteins were detected in normal human pancreas by immunohistochemistry with a monoclonal antibody (M3B) specific for gamma -carboxyglutamyl residues, Staining appeared to be localized to the glucagon-secreting alpha -cells in the islets of Langerhans, Consistent with this, sections from a glucagonoma were stained much more intensely with the M3B antibody than those from an insulinoma. A murine alpha -cell line (alpha TC1 Clone 9) was cultured and gamma -carboxylated polypeptides, identified immunologically as prothrombin, protein S and (tentatively) Gas6, were isolated from the intracellular compartment by chromatography on an M3B-coupled resin, As in liver, prothrombin is synthesized by alpha -cells as a gamma -carboxylated zymogen that can be cleaved by ecarin to form an active serine protease that is inhibited by hirudin, The pancreas thus appears to be a novel site of synthesis for certain vitamin K-dependent proteins.
Original languageEnglish
Pages (from-to)454-459
JournalBiochemical and Biophysical Research Communications
Volume283
Issue number2
DOIs
Publication statusPublished - 2001

Subject classification (UKÄ)

  • Biological Sciences

Keywords

  • γ-carboxylation
  • Gla
  • pancreas
  • protein S
  • prothrombin
  • vitamin K

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