Cooperativity in the binding of 1α,25‐dihydroxyvitamin D3 to the chick intestinal receptor

FEBS Letters

Norman, Anthony W.¹  Wilhelm, Francois¹ 

[1] Department of Biochemistry, University of California, Riverside, CA 92521, USA

关键词: Chick;    Intestine;    1;    25-Dihydroxyvitamin D3;    Receptor;    Cooperative behavior;    Affinity;   

DOI  :  10.1016/0014-5793(84)81320-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The binding of 1,25-dihydroxyvitamin D₃ [1,25(OH)₂D₃] to its chick intestinal receptor does not fit well to the linear regression line of Scatchard's model (r = −0.79; dissociation constant, K _d = 0.51 nM). In fact, a concave ‘hook’ curve describes the data better. By using the Hill analysis the linear fitting was improved (r= 0.99), the K _d was found to be 0.14 nM and the Hill coefficient (n _H) 1.42, which indicates a positive cooperativity in the binding of 1,25(OH)₂D₃ to its receptor. Further we found that K _d and n _H are strongly correlated (p < 0.001). These data suggest the existence of two ligand binding sites located in subunits for the 1,25(OH)₂D₃ receptor.

【 授权许可】

Unknown