A derivative of R-type cyanocobalamin binding proteins in the human intestine. A candidate antibacterial molecule

Biochim Biophys Acta. 1980 Dec 1;633(2):289-94. doi: 10.1016/0304-4165(80)90414-6.


Human jejunal fluid contains a protein which has a molecular radius of 3.37 nm, an Mr or 60600 and a mean pI of 3.35 and binds cobalamin with a K of 0.1 . 10(9) l/mol. This protein also couples cobalamin analogues lacking the nucleotide moiety, cross-reacts with R-type protein and is resistant to proteolysis in the intestine. These findings refute the hypothesis that cobalamin-analogue binders are present and effectively inhibit the bacterial uptake of analogues in the intestine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / metabolism*
  • Carrier Proteins / metabolism*
  • Chromatography, Gel
  • Humans
  • Intrinsic Factor / isolation & purification
  • Intrinsic Factor / metabolism
  • Isoelectric Focusing
  • Jejunum / analysis*
  • Macromolecular Substances
  • Molecular Weight
  • Transcobalamins / metabolism*


  • Anti-Bacterial Agents
  • Carrier Proteins
  • Macromolecular Substances
  • Transcobalamins
  • Intrinsic Factor