title: A derivative of R-type cyanocobalamin binding proteins in the human intestine. A candidate antibacterial molecule.
abstract: 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.
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D002850:Chromatography, Gel; D006801:Humans; D007437:Intrinsic Factor / Q000302:isolation & purification / Q000378:metabolism; D007525:Isoelectric Focusing; D007583:Jejunum / Q000032:analysis*; D046911:Macromolecular Substances; D008970:Molecular Weight; D014155:Transcobalamins / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D002352:Carrier Proteins; D046911:Macromolecular Substances; D014155:Transcobalamins; D007437:Intrinsic Factor