| Bioactivity | ZK168281 is a 25-carboxylic ester 1α,25(OH)2D3 analog and a pure VDR antagonist with a Kd value of 0.1 nM. ZK168281 is an effective inhibitor of the coactivator (CoA) interaction of its receptor[1]. |
| Target | Kd: 0.1 nM (VDR) |
| Invitro | ZK168281 resembles more the mouse constitutive androstane receptor (CAR) inverse agonist Androstanol in its ability to recruit corepressor (CoR) proteins. A salt bridge between the CoR and a conserved lysine in helix 4 of the nuclear receptor (NR) is central to this interaction, but also helix 12 was stabilized by direct contacts with residues of the CoR. Fixation of helix 12 in the antagonistic/inverse agonistic conformation prevents an energetically unfavorable free floatation of the C terminus[1]. |
| Name | ZK168281 |
| CAS | 186371-96-0 |
| Formula | C32H46O5 |
| Molar Mass | 510.70 |
| Appearance | Solid |
| Transport | Room temperature in continental US; may vary elsewhere. |
| Storage | 4°C, protect from light, stored under nitrogen *In solvent : -80°C, 6 months; -20°C, 1 month (protect from light, stored under nitrogen) |
| Reference | [1]. Lempiäinen H, et al. Antagonist- and inverse agonist-driven interactions of the vitamin D receptor and the constitutive androstane receptor with corepressor protein. Mol Endocrinol. 2005 Sep;19(9):2258-72. |