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Characterization of the vitamin B12-binding protein isolated from sow's milk and its affinity for cyanocobalamin and other corrinoids.
Braz J Med Biol Res. 1988; 21(5):883-94.BJ

Abstract

1. Unsaturated vitamin B12-binding protein was isolated from sow's milk whey by affinity chromatography on a vitamin B12-Sepharose column with a yield of 54% (3920-fold purification). The purified binding protein was homogeneous by the criteria of polyacrylamide gel electrophoresis and high speed sedimentation equilibrium. 2. The isolated vitamin B12-binding protein was a glycoprotein with 24% carbohydrates (fucose, galactose, mannose, galactosamine, glucosamine and sialic acid) and high levels of aspartic and glutamic acids. The protein which has a molecular weight of 61,800 determined by ultracentrifugation, consisted of a single polypeptide chain, bound vitamin B12 on an equimolar basis and had a partial specific volume of 0.697 ml/g (mechanical oscillator technique). 3. Its dissociation constant, Kd, for cyanocobalamin was 8.8 x 10(-10)M. The binding protein showed similar affinities for hydroxo-, methyl-, and adenosylcobalamin when compared to cyanocobalamin relative affinity ratios, but lower affinities (31-49%) for cobinamide, Co-alpha-[adenyl] cobamide and Co-alpha-[2-methyl-adenyl] cobamide. Therefore, the substitution of the axial ligand to the cobalt atom in the corrin ring of vitamin B12 had no effect on affinity, whereas the differences in the nucleotide part of the molecule caused a small decrease in energy of the interaction. 4. The present results indicate close similarity of the vitamin B12-binding protein from sow's milk to vitamin B12-binding proteins from other sources, especially those from human milk and from porcine gastric mucosa (nonintrinsic factor). Whether this similarity extends to antigenic and physiological properties remains to be investigated.

Authors+Show Affiliations

National Institute for Research in Dairying, Shinfield, Reading, United Kingdom.

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

3248237

Citation

Trugo, N M.. "Characterization of the Vitamin B12-binding Protein Isolated From Sow's Milk and Its Affinity for Cyanocobalamin and Other Corrinoids." Brazilian Journal of Medical and Biological Research = Revista Brasileira De Pesquisas Medicas E Biologicas, vol. 21, no. 5, 1988, pp. 883-94.
Trugo NM. Characterization of the vitamin B12-binding protein isolated from sow's milk and its affinity for cyanocobalamin and other corrinoids. Braz J Med Biol Res. 1988;21(5):883-94.
Trugo, N. M. (1988). Characterization of the vitamin B12-binding protein isolated from sow's milk and its affinity for cyanocobalamin and other corrinoids. Brazilian Journal of Medical and Biological Research = Revista Brasileira De Pesquisas Medicas E Biologicas, 21(5), 883-94.
Trugo NM. Characterization of the Vitamin B12-binding Protein Isolated From Sow's Milk and Its Affinity for Cyanocobalamin and Other Corrinoids. Braz J Med Biol Res. 1988;21(5):883-94. PubMed PMID: 3248237.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Characterization of the vitamin B12-binding protein isolated from sow's milk and its affinity for cyanocobalamin and other corrinoids. A1 - Trugo,N M, PY - 1988/1/1/pubmed PY - 1988/1/1/medline PY - 1988/1/1/entrez SP - 883 EP - 94 JF - Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas JO - Braz J Med Biol Res VL - 21 IS - 5 N2 - 1. Unsaturated vitamin B12-binding protein was isolated from sow's milk whey by affinity chromatography on a vitamin B12-Sepharose column with a yield of 54% (3920-fold purification). The purified binding protein was homogeneous by the criteria of polyacrylamide gel electrophoresis and high speed sedimentation equilibrium. 2. The isolated vitamin B12-binding protein was a glycoprotein with 24% carbohydrates (fucose, galactose, mannose, galactosamine, glucosamine and sialic acid) and high levels of aspartic and glutamic acids. The protein which has a molecular weight of 61,800 determined by ultracentrifugation, consisted of a single polypeptide chain, bound vitamin B12 on an equimolar basis and had a partial specific volume of 0.697 ml/g (mechanical oscillator technique). 3. Its dissociation constant, Kd, for cyanocobalamin was 8.8 x 10(-10)M. The binding protein showed similar affinities for hydroxo-, methyl-, and adenosylcobalamin when compared to cyanocobalamin relative affinity ratios, but lower affinities (31-49%) for cobinamide, Co-alpha-[adenyl] cobamide and Co-alpha-[2-methyl-adenyl] cobamide. Therefore, the substitution of the axial ligand to the cobalt atom in the corrin ring of vitamin B12 had no effect on affinity, whereas the differences in the nucleotide part of the molecule caused a small decrease in energy of the interaction. 4. The present results indicate close similarity of the vitamin B12-binding protein from sow's milk to vitamin B12-binding proteins from other sources, especially those from human milk and from porcine gastric mucosa (nonintrinsic factor). Whether this similarity extends to antigenic and physiological properties remains to be investigated. SN - 0100-879X UR - https://www.unboundmedicine.com/medline/citation/3248237/Characterization_of_the_vitamin_B12_binding_protein_isolated_from_sow's_milk_and_its_affinity_for_cyanocobalamin_and_other_corrinoids_ L2 - https://www.lens.org/lens/search/patent/list?q=citation_id:3248237 DB - PRIME DP - Unbound Medicine ER -