Primary Information
BoMiProt ID	Bomi148
Protein Name	Vitamin D-binding protein
Organism	Bos taurus
Uniprot ID	Q3MHN5
Milk Fraction	Whey
Ref Sequence ID	NP_001030457.1
Aminoacid Length	474
Molecular Weight	53342
FASTA Sequence	Download
Gene Name	GC
Gene ID	530076
Protein Existence Status	Reviewed: Experimental evidence at transcript level
Secondary Information
Presence in other biological fluids/tissue/cells	Serum,
Protein Function	Role in the transport of vitamin D metabolites; maintains total levels of vitamin D and regulates the amounts of free (unbound) vitamin D available for specific tissues and cell types to utilize; binds actin and fatty acids preventing their polymerization; immune functions such as in B-cells, DBP seems to participate in the linkage of surface immunoglobulins
Biochemical Properties	Associated and copurified with actin; existence of three major polymorphic forms -GC1F, GC1S and GC2; most DBP circulates without any vitamin D ligands attached; DBP binds actin with an affinity of 1 109 M^(–1) and fatty acids with reported affinity of 6–7 105 M(^–1)
Significance in milk	Colostrum could be a rich source of vitamin D associated with DBP and could play an important role in the intake of vitamin D sterols in the newborn.
PTMs	Glycosylated; GC1 forms have glycosylations at positions 418 and 420, whereas GC2 has glycosylation only at 418; trisaccharides as most frequent in GC1 with lesser amounts of disaccharides as found in humans
Site(s) of PTM(s) N-glycosylation, O-glycosylation, Phosphorylation
Predicted Disorder Regions	17-28,107-127
DisProt Annotation
TM Helix Prediction	No TM helices
Bibliography	1. Ena, J., Pérez, M. D., Aranda, P., Sánchez, L., and Calvo, M. (1992) Presence and changes in the concentration of vitamin D-binding protein throughout early lactation in human and bovine colostrum and milk. J. Nutr. Biochem. 3, 498–502. 2. HIRSCHFELD, J. (1959) Immune-electrophoretic demonstration of qualitative differences in human sera and their relation to the haptoglobins. Acta Pathol. Microbiol. Scand. 47, 160–168. 3. Svasti, J., Kurosky, A., Bennett, A., and Bowman, B. H. (1979) Molecular basis for the three major forms of human serum vitamin D binding protein (group-specific component). Biochemistry 18, 1611–1617. 4. Cooke, N. E. and David, E. V. (1985) Serum vitamin D-binding protein is a third member of the albumin and alpha fetoprotein gene family. J. Clin. Invest. 76, 2420–2424. 5. Svasti, J. and Bowman, B. H. (1978) Human group-specific component. Changes in electrophoretic mobility resulting from vitamin D binding and from neuraminidase digestion. J. Biol. Chem. 253, 4188–4194. 6. Ravnsborg, T., Olsen, D. T., Thysen, A. H., Christiansen, M., Houen, G., and Højrup, P. (2010) The glycosylation and characterization of the candidate Gc macrophage activating factor. Biochim. Biophys. Acta 1804, 909–917. 7. Mc Leod, J. F., Kowalski, M. A., and Haddad, J. G. (1989) Interactions among serum vitamin D binding protein, monomeric actin, profilin, and profilactin. J. Biol. Chem. 264, 1260–1267. 8. Calvo, M. and Ena, J. M. (1989) Relations between vitamin D and fatty acid binding properties of vitamin D-binding protein. Biochem. Biophys. Res. Commun. 163, 14–17.