1-ALPHA,25-DIHYDROXYVITAMIN D-3-3-BETA-BROMOACETATE, AN AFFINITY-LABELING ANALOG OF 1-ALPHA,25-DIHYDROXYVITAMIN D-3 RECEPTOR

In this communication we describe the synthesis of 1 alpha,25-dihydroxyvitamin D-3-3 beta-bromoacetate [1,25(OH)(2)-BE], an analog of 1 alpha,25-dihydroxyvitamin D-3 [1,25(OH)(2)D-3], as a part of our ongoing interest in characterizing the hormone-binding domain of the 1 alpha,25-dihydroxyvitamin D-3 receptor (VDR). We carried out several binding studies of 1,25(OH)(2)-BE with chick intestinal VDR preparations to demonstrate that 1,25(OH)(2)-BE is capable of blocking the entry of 1,25(OH)(2)D-3 into its binding pocket and possibly covalently linking to the VDR molcule. (C) 1994 Academic Press, Inc.