Abstract
The binding of 1,25-dihydroxyvitamin D3-receptor complexes from chick intestinal cytosol to DNA-cellulose and isolated intestinal nuclei is inhibited by several dye-ligands in a dose-dependent manner. Concentrations of Cibacron blue F3GA, blue dextran, Procion red HE3B, and Green A dye causing 50% competition for receptor binding to DNA-cellulose ranged from 2.8 to 3.6 microM. A structural analogue of the anthraquinone moiety of Cibacron blue F3GA, bromaminic acid, was 111-fold less potent in inhibiting DNA-cellulose binding. Moreover, the inhibitory effects of these dye-ligands is not due to a simple electrostatic effect, since two other polyanions, heparin and poly-L-glutamate, are much less effective. Whereas dye-ligands can cause the release of receptors bound to DNA-cellulose, they do not alter the dissociation of 1,25-dihydroxyvitamin D3 from its receptor nor do they affect the apparent equilibrium binding constant of the receptor or the concentration of available sterol-binding sites. The inhibition of binding by dye-ligands is competitive with respect to DNA-cellulose binding, indicating that the effect of these dyes is at a domain common to polynucleotides.
MolPharm articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|