scholarly journals Properties of Folate Binding Protein Purified from Cow's Milk

2012 ◽  
Vol 19 (3) ◽  
pp. 105-109
Author(s):  
A SUBANDRATE ◽  
DWIRINI RETNO GUNARTI ◽  
MOHAMAD SADIKIN
Keyword(s):  
Binding Protein ◽  
Cow’S Milk ◽  
Folate Binding Protein ◽  
Cow's Milk

Binding of Radiolabeled Folate and 5-Methyltetrahydrofolate to Cow's Milk Folate Binding Protein at pH 7.4 and 5.0. Relationship to Concentration and Polymerization Equilibrium of the Purified Protein

2001 ◽  
Vol 21 (6) ◽  
pp. 733-743 ◽  
Author(s):  
Jan Holm ◽  
Steen Ingemann Hansen
Keyword(s):  
Ligand Binding ◽  
Binding Affinity ◽  
Conformational Changes ◽  
Protein Conformation ◽  
Binding Protein ◽  
Cow’S Milk ◽  
Folate Binding Protein ◽  
Cow's Milk ◽  
Polymerization Equilibrium ◽  
Methyl Tetrahydrofolate

Binding of folate (pteroylglutamate) and 5-methyltetrahydrofolate, the major endogenous form of folate, to folate binding protein purified from cow's milk was studied at 7°C to avoid degradation of 5-methyltetrahydrofolate. Both folates dissociate rapidly from the protein at pH 3.5, but extremely slowly at pH 7.4, most likely due to drastic changes in protein conformation occurring after folate binding. Dissociation of 5-methyltetrahydrofolate showed no increase at 37°C suggesting that protein-bound-5-methyltetrahydrofolate is protected against degradation. Binding displayed two characteristics, positive cooperativity and a binding affinity that increased with decreasing concentrations of the protein. The binding affinity of folate was somewhat greater than that of 5-methyl tetrahydrofolate, in particular at pH 5.0. Ligand-bound protein exhibited concentration-dependent polymerization (8-mers formed at 13 μM) at pH 7.4. At pH 5.0, only folate-bound forms showed noticeable polymerization. The fact that folate at pH 5.0 surpasses 5-methyltetrahydrofolate both with regard to binding affinity and ability to induce polymerization suggests that ligand binding is associated with conformational changes of the protein which favor polymerization.

Ionic Charge, Hydrophobicity and Tryptophan Fluorescence of the Folate Binding Protein Isolated from Cow's Milk

2001 ◽  
Vol 21 (3) ◽  
pp. 305-313 ◽  
Author(s):  
Jan Holm ◽  
Steen Ingemann Hansen ◽  
Mimi Høier-Madsen
Keyword(s):  
Ligand Binding ◽  
Binding Protein ◽  
Tryptophan Fluorescence ◽  
Exchange Chromatography ◽  
Cow’S Milk ◽  
Conformation Change ◽  
Ionic Charge ◽  
Folate Binding Protein ◽  
Cow's Milk ◽  
Isoelectric Points

A high-affinity folate binding protein was isolated and purified from cow's milk by a combination of cation exchange chromatography and methotrexate affinity chromatography. Chromatofocusing studies revealed that the protein possessed isoelectric points in the pH-interval 8–7. Polymers of the protein prevailing at pH values close to the isoelectric points seemed to be more hydrophobic than monomers present at pH 5.0 as evidenced by hydrophobic interaction chromatography and turbidity (absorbance at 340 nm) in aqueous buffer solutions (pH 5–8). Ligand binding seemed to induce a conformation change that decreased the hydrophobicity of the protein. In addition, Ligand binding quenched the tryptophan fluorescence of folate binding protein suggesting that tryptophan is present at the binding site and/or ligand binding induces a conformation change that affects tryptophan environment in the protein. There was a noticeable discordance between the ability of individual folate analogues to compete with folate for binding and the quenching effect.

Effect of Methotrexate on Folate Binding to a Folate Binding Protein in Cow's Milk

2009 ◽  
Vol 42 (1) ◽  
pp. 77-80 ◽  
Author(s):  
Jan Holm ◽  
Steen Ingemann Hansen ◽  
Jørgen Lyngbye
Keyword(s):  
Binding Protein ◽  
Cow’S Milk ◽  
Folate Binding Protein ◽  
Cow's Milk

Effect of Hydrogen Ion Concentration and Buffer Composition on Ligand Binding Characteristics and Polymerization of Cow's Milk Folate Binding Protein

2001 ◽  
Vol 21 (6) ◽  
pp. 745-753 ◽  
Author(s):  
Jan Holm ◽  
Steen Ingemann Hansen
Keyword(s):  
Ligand Binding ◽  
Binding Protein ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Cow’S Milk ◽  
Folate Binding Protein ◽  
Hydrogen Ion Concentration ◽  
Binding Characteristics ◽  
Cow's Milk ◽  
Buffer Composition

The ligand binding and aggregation behavior of cow's milk folate binding protein depends on hydrogen ion concentration and buffer composition. At pH 5.0, the protein polymerizes in Tris-HCl subsequent to ligand binding. No polymerization occurs in acetate, and binding is markedly weaker in acetate or citrate buffers as compared to Tris-HCl. Polymerization of ligand-bound protein was far more pronounced at pH 7.4 as compared to pH 5.0 regardless of buffer composition. Binding affinity increased with decreasing concentration of protein both at pH 7.4 and 5.0. At pH 5.0 this effect seemed to level off at a protein concentration of 10−6 M which is 100–1000 fold higher than at pH 7.4. The data can be interpreted in terms of complex models for ligand binding systems polymerizing both in the absence or presence of ligand (pH 7.4) as well as only subsequent to ligand binding (pH 5.0).

Rabbit antibodies against the folate binding protein from cow's milk. Production, characterization and use for development of an enzyme-linked immunosorbent assay (ELISA)

1986 ◽  
Vol 6 (10) ◽  
pp. 895-900 ◽  
Author(s):  
Mimi Høier-Madsen ◽  
Steen Ingemann Hansen ◽  
Jan Holm
Keyword(s):  
Immunosorbent Assay ◽  
Binding Proteins ◽  
Binding Protein ◽  
Cross Reactivity ◽  
Cow’S Milk ◽  
Enzyme Linked Immunosorbent Assay ◽  
Folate Binding Protein ◽  
Milk Whey ◽  
Cow's Milk ◽  
Folate Binding Proteins

Rabbit antibodies to purified folate binding protein from cow's milk whey were used for development of a two-site enzyme-linked immunosorbent assay (ELISA) for quantitation of bovine folate binding proteins, The folate binding proteins in human milk and serum showed no cross-reactivity. A partial saturation of purified bovine folate binder with folate gave rise to an increased antigenicity probably due to a ligand (folate)-induced exposure of antigenic sites on the protein.

scholarly journals Isolation of the folate-binding protein from cow's milk by the use of affinity chromatography

FEBS Letters ◽  
1972 ◽  
Vol 20 (3) ◽  
pp. 302-306 ◽  
Author(s):  
D.N. Salter ◽  
J.E. Ford ◽  
K.J. Scott ◽  
P. Andrews
Keyword(s):  
Affinity Chromatography ◽  
Binding Protein ◽  
Cow’S Milk ◽  
Folate Binding Protein ◽  
Cow's Milk

scholarly journals The complete amino acid sequence of the folate-binding protein from cow's milk

1984 ◽  
Vol 49 (1) ◽  
pp. 123-131 ◽  
Author(s):  
IB Svendsen ◽  
Steen Ingemann Hansen ◽  
Jan Holm ◽  
Jørgen Lyngbye
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Binding Protein ◽  
Cow’S Milk ◽  
Folate Binding Protein ◽  
Cow's Milk ◽  
Complete Amino Acid Sequence

Dependence of aggregation and ligand affinity on the concentration of the folate-binding protein from cow's milk

1983 ◽  
Vol 226 (2) ◽  
pp. 636-642 ◽  
Author(s):  
Steen Ingemann Hansen ◽  
Jan Holm ◽  
Jørgen Lyngbye ◽  
Torben Graves Pedersen ◽  
Ib Svendsen
Keyword(s):  
Binding Protein ◽  
Cow’S Milk ◽  
Folate Binding Protein ◽  
Cow's Milk ◽  
Ligand Affinity
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