vitamin D binding protein, Gc globulin; group-specific component

^[1]^[2]^[3]^[4]

Function

multifunctional protein found in plasma, ascitic fluid, cerebrospinal fluid, & urine & on the surface of many cell types
in plasma, it carries the vitamin D sterols & prevents polymerization of actin by binding its monomers
VDBP associates with membrane-bound immunoglobulin on the surface of B-lymphocytes & with IgG Fc receptor on the membranes of T-lymphocytes

over 80 variants of human DBP have been identified
most common alleles are called GC*1F, GC*1S, & GC*2
both total 25-hydroxyvitamin D & vitamin D-binding protein are lower in blacks than in whites
- 25-hydroxyvitamin D:
  - 15.6 +/- 0.2 ng/mL vs 25.8 +/- 0.4 ng/mL
- vitamin D-binding protein:
  - 168 +/- 3 ug/mL vs 337 +/- 5 ug/mL^[4]

↑ UniProt http://www.uniprot.org/uniprot/P02774.html
↑ OMIM https://mirror.omim.org/entry/139200
↑ Clinical Diagnosis & Management by Laboratory Methods, J.B. Henry (ed), W.B. Saunders Co., Philadelphia, PA. 1991, pg 224
↑ ^4.0 ^4.1 Powe CE et al. Vitamin D-binding protein and vitamin D status of black Americans and white Americans. N Engl J Med 2013 Nov 21; 369:1991 <PubMed> PMID: https://www.ncbi.nlm.nih.gov/pubmed/24256378 <Internet> http://www.nejm.org/doi/full/10.1056/NEJMoa1306357