title: Solubilization of 1,25-dihydroxyvitamin D3 receptor with pyridoxal 5'-phosphate from hen intestinal mucosa.
abstract: 1,25-Dihydroxyvitamin D3(1,25-(OH)2D3) receptor was solubilized in cytosol fractions upon homogenization of hen intestinal mucosa with pyridoxal 5'-phosphate contained in a low ionic strength buffer. Pyridoxal 5'-phosphate did not inhibit the binding of 1,25-(OH)2D3 to its receptor. The receptor solubilized with pyridoxal 5'-phosphate was similar to the KCl-solubilized receptor in its binding affinity to the hormone and sedimentation coefficient. A majority (greater than 90%) of the mucosal 1,25-(OH)2D3 receptors were obtained as associating with crude chromatin which was prepared with a low ionic strength buffer, and this fraction of the receptor was solubilized with pyridoxal 5'-phosphate. Ten millimolar pyridoxal 5'-phosphate was as effective as approx 0.2 M KCl in solubilizing the receptor from the crude chromatin. Pyridoxal 5'-phosphate also showed a potency to dissociate the 1,25-(OH)2D3-receptor complex previously bound to DNA-cellulose. Pyridoxal 5'-phosphate-related compounds such as pyridoxamine 5'-phosphate and pyridoxal did not show this potency. These results suggest that pyridoxal 5'-phosphate reduced the interaction of 1,25-(OH)2D3 receptor with its nuclear binding components without inhibiting the binding of the receptor to the hormone.
mesh_terms: D000818:Animals; D002482:Cellulose / Q000031:analogs & derivatives; D002645:Chickens; D002843:Chromatin / Q000378:metabolism; D004247:DNA / Q000031:analogs & derivatives / Q000378:metabolism; D005260:Female; D007413:Intestinal Mucosa / Q000032:analysis*; D007700:Kinetics; D009994:Osmolar Concentration; D011092:Polyethylene Glycols; D011189:Potassium Chloride; D011730:Pyridoxal; D011732:Pyridoxal Phosphate; D011733:Pyridoxamine / Q000031:analogs & derivatives; D011736:Pyridoxine; D018167:Receptors, Calcitriol; D011987:Receptors, Steroid / Q000302:isolation & purification*; D012995:Solubility
chemical_list: D002843:Chromatin; C033190:DNA-cellulose; D018167:Receptors, Calcitriol; D011987:Receptors, Steroid; D011730:Pyridoxal; D011092:Polyethylene Glycols; D011732:Pyridoxal Phosphate; D011733:Pyridoxamine; D011189:Potassium Chloride; D002482:Cellulose; D004247:DNA; D011736:Pyridoxine; C010627:pyridoxamine phosphate