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The interaction of 1,25‐dihydroxyvitamin D 3 with its intestinal mucosa receptor: Kinetic parameters and structural requirements
Author(s) -
Putkey John A.,
Wecksler Wayne R.,
Norman Anthony W.
Publication year - 1978
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02533752
Subject(s) - calcitriol receptor , cytosol , intestinal mucosa , vitamin d and neurology , receptor , ligand (biochemistry) , chemistry , vitamin , biochemistry , biophysics , biology , endocrinology , medicine , enzyme
Vitamin D 3 and its metabolites comprise an endocrine system which plays a critical role in calcium homeostasis. The active form of vitamin D 3 is 1,25‐dihydroxyvitamin D 3 [1,25(OH) 2 D 3 ]. Chromatin localization of 1,25(OH) 2 D 3 and sucrose density gradient centrifutation have demonstrated the presence of an intestinal mucosa cytosol receptor which specifically binds 1,25(OH) 2 D 3 . The kinetic parameters of 1,25(OH) 2 D 3 binding to its receptor have been determined by hydroxylapatite and reconstituted chromatin cytosol assays. Utilization of these assays has also permitted a determination of the precise structural requirements of the vitamin D ligand for the intestinal receptor. Furthermore, it has been possible to propose two receptor‐ligand models which are capable of accommodating the conformationaly modile A ring of the vitamin D seco‐steroids.