Department of Biochemistry, University of Arizona Tucson, Arizona 85724 USA
Abstract:
Rat kidney cytosol contains a 3.3 S high affinity binding component for 1,25-dihydroxyvitamin D3 as detected by DNA-cellulose chromatography and subsequent sucrose gradient analysis. The semipurified aporeceptor demonstrates specificity for 1,25-dihydroxyvitamin D3 and an apparent dissociation constant for this sterol-hormone of 3.4 × 10?10M at 25°C. The physicochemical properties of this binding component are in agreement with those observed for the chick intestinal 1,25-dihydroxyvitamin D3 receptor, suggesting that this component may function as a specific receptor for the hormone in the kidney.