Biomaterial Database

Cooperativity in the binding of 1 alpha,25-dihydroxyvitamin D3 to the chick intestinal receptor. 1984

F Wilhelm, and A W Norman

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, Kd = 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 Kd was found to be 0.14 nM and the Hill coefficient (nH) 1.42, which indicates a positive cooperativity in the binding of 1,25(OH)2D3 to its receptor. Further we found that Kd and nH are strongly correlated (p less than 0.001). These data suggest the existence of two ligand binding sites located in subunits for the 1,25(OH)2D3 receptor.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D011987	Receptors, Steroid	Proteins found usually in the cytoplasm or nucleus that specifically bind steroid hormones and trigger changes influencing the behavior of cells. The steroid receptor-steroid hormone complex regulates the transcription of specific genes.	Corticosteroid Receptors,Receptors, Corticosteroid,Steroid Receptors,Corticosteroid Receptor,Receptors, Steroids,Steroid Receptor,Receptor, Corticosteroid,Receptor, Steroid,Steroids Receptors
D002117	Calcitriol	The physiologically active form of vitamin D. It is formed primarily in the kidney by enzymatic hydroxylation of 25-hydroxycholecalciferol (CALCIFEDIOL). Its production is stimulated by low blood calcium levels and parathyroid hormone. Calcitriol increases intestinal absorption of calcium and phosphorus, and in concert with parathyroid hormone increases bone resorption.	1 alpha,25-Dihydroxycholecalciferol,1 alpha,25-Dihydroxyvitamin D3,1, 25-(OH)2D3,1,25(OH)2D3,1,25-Dihydroxycholecalciferol,1,25-Dihydroxyvitamin D3,1 alpha, 25-dihydroxy-20-epi-Vitamin D3,1,25(OH)2-20epi-D3,1,25-dihydroxy-20-epi-Vitamin D3,20-epi-1alpha,25-dihydroxycholecaliferol,Bocatriol,Calcijex,Calcitriol KyraMed,Calcitriol-Nefro,Decostriol,MC-1288,MC1288,Osteotriol,Renatriol,Rocaltrol,Silkis,Sitriol,Soltriol,Tirocal,1 alpha,25 Dihydroxyvitamin D3,1,25 Dihydroxycholecalciferol,1,25 Dihydroxyvitamin D3,1,25 dihydroxy 20 epi Vitamin D3,Calcitriol Nefro,D3, 1 alpha,25-Dihydroxyvitamin,D3, 1,25-Dihydroxyvitamin,D3, 1,25-dihydroxy-20-epi-Vitamin,KyraMed, Calcitriol,MC 1288
D002645	Chickens	Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.	Gallus gallus,Gallus domesticus,Gallus gallus domesticus,Chicken
D004386	Duodenum	The shortest and widest portion of the SMALL INTESTINE adjacent to the PYLORUS of the STOMACH. It is named for having the length equal to about the width of 12 fingers.	Duodenums
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D018167	Receptors, Calcitriol	Proteins, usually found in the cytoplasm, that specifically bind calcitriol, migrate to the nucleus, and regulate transcription of specific segments of DNA with the participation of D receptor interacting proteins (called DRIP). Vitamin D is converted in the liver and kidney to calcitriol and ultimately acts through these receptors.	Calcitriol Receptors,Cholecalciferol Receptors,Receptors, Vitamin D,Vitamin D 3 Receptors,Vitamin D Receptors,1,25-Dihydroxycholecalciferol Receptor,1,25-Dihydroxycholecalciferol Receptors,1,25-Dihydroxyvitamin D 3 Receptor,1,25-Dihydroxyvitamin D3 Receptor,1,25-Dihydroxyvitamin D3 Receptors,Calcitriol Receptor,Receptors, 1,25-Dihydroxyvitamin D 3,Receptors, Cholecalciferol,Receptors, Vitamin D 3,Receptors, Vitamin D3,Vitamin D 3 Receptor,Vitamin D Receptor,Vitamin D3 Receptor,Vitamin D3 Receptors,1,25 Dihydroxycholecalciferol Receptor,1,25 Dihydroxycholecalciferol Receptors,1,25 Dihydroxyvitamin D 3 Receptor,1,25 Dihydroxyvitamin D3 Receptor,1,25 Dihydroxyvitamin D3 Receptors,D Receptor, Vitamin,D Receptors, Vitamin,D3 Receptor, 1,25-Dihydroxyvitamin,D3 Receptor, Vitamin,D3 Receptors, 1,25-Dihydroxyvitamin,D3 Receptors, Vitamin,Receptor, 1,25-Dihydroxycholecalciferol,Receptor, 1,25-Dihydroxyvitamin D3,Receptor, Calcitriol,Receptor, Vitamin D,Receptor, Vitamin D3,Receptors, 1,25-Dihydroxycholecalciferol,Receptors, 1,25-Dihydroxyvitamin D3