Disease relevance of FBP

• Enrichment cultures were streaked on a plating medium composed of Brucella agar, hematin solution, FBP supplement, and the above antibiotics [1].
• Median values of FBP for ulcerative colitis were: 13 units/ml (4-74), for Crohn's disease: 14 units/ml (7-73), and healthy volunteers: 14 units/ml (4-51) [2].
• This result, taken together with the peptide sequence data, indicates the expression of at least two homologous folate binding proteins in placenta, one of which appears to be identical with the folate binding protein from human milk and nasopharyngeal epidermoid carcinoma (KB) cells; the cDNA sequence obtained corresponds to the other protein [3].
• Serum antibodies to cow's milk folate-binding protein in patients with chronic inflammatory bowel disease [2].

High impact information on FBP

• The differential polarized distribution of the reduced- folate transporter (RFT-1) and folate receptor alpha (FRalpha), the two proteins involved in the transport of folate, has been characterized in normal mouse retinal pigment epithelium (RPE) and in cultured human RPE cells [4].
• Expression and differential polarization of the reduced-folate transporter-1 and the folate receptor alpha in mammalian retinal pigment epithelium [4].
• The complete amino acid sequence of a human folate binding protein from KB cells determined from the cDNA [5].
• Eight of the nine pairs of cysteines involved in disulfide bonds in RfBP are conserved in folate-binding protein, as are all of the tryptophan residues [6].
• The two proteins used were (i) antibody specific for folic acid and (ii) the folate-binding protein from bovine milk [7].

Biological context of FBP

• In this report we describe a novel finding that the 104 kDa chaperone protein exhibits affinity for iron containing proteins such as transferrins from several species, human lactoferrin and microbial ferric binding protein (FBP) [8].
• Stabilization of milk folates may be a role of FBP and would improve the bioavailability of milk folate to newborns and other consumers [9].
• Native state FBP recently has been shown to enhance the intestinal absorption of folacin, whereas the FBP of pasteurized milk is ineffective [10].
• The technique was applied to the measurement of active FBP content of consumer milks, the heat classification of skim milk powders manufactured under a wide range of thermal processing protocols, and change during early bovine lactation [11].
• The amide I region pointed to a beta-sheet to alpha-helix transition upon ligation in acetate and phosphate buffers, and the formation of intermolecular beta-sheet was indicated at pH 5.0, in agreement with a dimerization of FBP taking place at this pH [12].

Anatomical context of FBP

• METHODS: The transport of [3H]-folic acid and [14C]-5-CH3-H4folate across enterocytes was studied in the presence or absence of bovine FBP using monolayers of Caco-2 cells grown on semi-permeable inserts in a two-compartment model [13].
• 1. The influence of goat's-milk folate-binding protein (FBP) on the uptake of 5-methyltetrahydrofolate (MTHF) by brush-border-membrane vesicles prepared from the small intestine of the 6-d-old goat was investigated using a rapid-filtration assay [14].
• 5. 5. The relation between pH and 125I-labelled FBP binding to the membranes was similar to that for uptake of MTHF, with an optimum at pH 5 [14].
• 9. It was concluded that a folate transport mechanism mediated by the FBP in milk exists at the intestinal brush border of neonatal goats [14].
• Surface plasmon resonance analysis shows binding of bovine and human milk FBP to immobilized megalin, but not to low density lipoprotein receptor related protein [15].

Associations of FBP with chemical compounds

• Ligand binding characteristics and aggregation behavior of purified cow's milk folate binding protein depends on the presence of amphiphatic substances including cholesterol, phospholipids, and synthetic detergents [16].
• Folate binding to FBP results in significant changes in the c.d. spectrum [17].
• In the course of optimizing CE separation conditions for FBP purified from cow's milk we discovered a novel specific heparin-binding activity of FBP by affinity CE [18].
• Folate binding also leads to strong quenching of FBP tryptophan fluorescence [17].
• The guanidinium chloride-induced unfolding of FBP is shown to be a multistate process [17].

Other interactions of FBP

• Automated, rapid, sensitive, and label-free biosensor-based immunoassays for immunoglobulin G (IgG), folate binding protein, lactoferrin, and lactoperoxidase in bovine milk using surface plasmon resonance optical detection with direct binding assay format are described [19].

Analytical, diagnostic and therapeutic context of FBP

• Folate binding protein was purified from cow's milk by a combination of cation exchange chromatography and methotrexate-AH-sepharose affinity chromatography [16].
• Anion-exchange chromatography indicated no major electrostatic differences in the FBP of these products, although gel-filtration chromatography provided evidence of enhanced FBP aggregation in the pasteurized whey protein concentrate [10].
• The HPLC and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) results indicate the formation of three complexes after the binding of G5.75Ac-FA4 with FBP [20].
• We used rabbit anti-bovine milk antibody and ELISA to measure FBP [21].
• A longitudinal study will determine if these changes in FBP concentrations precede tumor onset [21].

References