Serum Retinol Binding Protein 4 (human recombinant)

Human serum retinol binding protein 4 (sRBP4) binds to one equivalent of vitamin A and is one of the major retinol carriers found in the blood of mammals. Human sRBP4 is a monomeric 21 kDa beta-sheet-rich protein that contains three disulfide bonds and belongs to the lipocalin protein family. In plasma, sRBP4 typically forms a 1:1 complex with the 55 kDa tetrameric protein transthyretin (TTR) which prevents RBP from being removed from the plasma by glomerular filtration. Recent studies have shown that sRBP4 is an adipocyte-derived "signal" that may contribute to the pathogenesis of type 2 diabetes. Elevation of sRBP4 causes systemic insulin resistance, whereas reduced serum concentrations of sRBP4 improves insulin action. Cayman's human recombinant sRBP4 contains a C-terminal hexahistidine tag. The purified protein was characterized for its retinol binding activity.Synonyms: RBP4, sRBP4. Purity: >95%. Source: Recombinant His-tagged protein purified from E. coli. MW: ~21 kDa. Formulation: (Request formulation change), 50 mM sodium phosphate, pH 8.2, with 100 mM sodium chloride and 20% glycerol.