| First Author | Daiger SP | Year | 1975 |
| Journal | Proc Natl Acad Sci U S A | Volume | 72 |
| Issue | 6 | Pages | 2076-80 |
| PubMed ID | 49052 | Mgi Jnum | J:20200 |
| Mgi Id | MGI:68558 | Doi | 10.1073/pnas.72.6.2076 |
| Citation | Daiger SP, et al. (1975) Group-specific component (Gc) proteins bind vitamin D and 25-hydroxyvitamin D. Proc Natl Acad Sci U S A 72(6):2076-80 |
| abstractText | Group-specific component (Gc) proteins are human plasma proteins for which a worldwide polymorphism exists. As yet no functional role has been assigned this protein. We show that the products of both Gc alleles, proteins Gc 1 and Gc 2 (distinguished electrophoretically), bind substantial quantities of vitamin D and 25-hydroxyvitamin D. Three lines of evidence are reported: (1) Polyacrylamide gel electrophoresis and autoradiography of serum labeled with (14-C)vitamin D3 revealed patterns of radioactive bands identical to those expected of the two Gc alleles. Population gene frequencies for these proteins binding vitamin D were in the range of those reported for Gc, and individuals of known Gc phenotype were found to have the corresponding vitamin-D-binding phenotype. (2) Immunoelectrophoresis and autoradiography of labeled serum reacted against antiserum to human Gc revealed labeling by (14-C)vitamin D3 of Gc-antibody precipitation ares. (3) (14-C)vitamin D3 or 25-hydroxy(3-H)vitamin D3 was found to coprecipitate specifically with Gc in serum incubated with Gc antiserum. Use of these techniques demonstrated further that plasma proteins that bind vitamin D and that are immunologically similar to human Gc are found in mouse, rat, cow, horse, dog, rhesus monkey, and chimpanzee. We propose that Gc and vitamin-D-binding alpha-globulin are in fact the same portein, and that the ability of Gc to bind vitamin D may be directly related to the action of selection on this locus. These techniques may also find application in the study of other plasms transport proteins. |
