• Purity

  >95%, by SDS-PAGE with silver staining.

• Endotoxin Level

  <1.0 EU per 1 μg of the protein by the LAL method.  

• Activity

  Measured by its ability to inhibit Wnt induced TCF reporter activity in HEK293 human embryonic kidney cells. Recombinant Human Dkk-1 (Catalog # 5439-DK/CF) inhibits a constant dose of 500 ng/mL of Recombinant Human Wnt-3a (Catalog # ). The ED    ₅₀ for this effect is 10-60 ng/mL. Measured by its ability to inhibit Wnt-3a-induced alkaline phosphatase production by MC3T3‑E1 mouse preosteoblast cells. The ND    ₅₀ for this effect is 0.03‑0.15 μg/mL in the presence of 10 ng/mL of Recombinant Mouse Wnt‑3a (Catalog # ).

• Source

  Spodoptera frugiperda,     Sf 21 (baculovirus)-derived Thr32-His266

• Accession #

• N-terminal Sequence    
  Analysis

  Thr32

• Predicted Molecular Mass

  25.8 kDa

• SDS-PAGE

  33-38 kDa, reducing conditions

Carrier Free

What does CF mean?

CF stands for Carrier Free (CF). We typically add Bovine Serum Albumin (BSA) as a carrier protein to our recombinant proteins. Adding a carrier protein enhances protein stability, increases shelf-life, and allows the recombinant protein to be stored at a more dilute concentration. The carrier free version does not contain BSA.

What formulation is right for me?

In general, we advise purchasing the recombinant protein with BSA for use in cell or tissue culture, or as an ELISA standard. In contrast, the carrier free protein is recommended for applications, in which the presence of BSA could interfere.

Data Images

Background: Dkk-1

Dickkopf related protein 1 (Dkk-1) is the founding member of the Dickkopf family of proteins that includes Dkk-1, -2, -3, -4, and a related protein, Soggy (1, 2). Dkk proteins are secreted proteins that contain two conserved cysteine-rich domains separated by a linker region. Each domain contains ten cysteine residues (1‑3). Mature human Dkk-1 is a 40 kDa glycosylated protein that shares 86%, 87%, 90% and 91% aa sequence identity with mouse, rat, rabbit and bovine Dkk-1, respectively. It also shares 42% and 36% aa identity with human Dkk-2 and Dkk-4, respectively. Dkk-1 and Dkk-4 are well documented antagonists of the canonical Wnt signaling pathway (1, 2). This pathway is activated by Wnt engagement of a receptor complex composed of the Frizzled proteins and one of two low-density lipoprotein receptor-related proteins, LRP5 or LRP6 (4). Dkk-1 antagonizes Wnt by forming ternary complexes of LRP5/6 with Kremen1 or Kremen2 (4, 5). Dkk‑1/LRP6/Krm2 complex internalization has been shown to down-regulate Wnt signaling (4, 5). Dkk-1 is expressed throughout development and antagonizes Wnt-7a during limb development (6, 7). Other sites of expression include developing neurons, hair follicles and the retina of the eye (8, 9). The balance between Wnt signaling and Dkk-1 inhibition is critical for bone formation and homeostasis (10). Insufficient or excess Dkk-1 activity in bone results in increased or decreased bone density, respectively (8, 11). In adults, Dkk-1 is expressed in osteoblasts and osteocytes, and neurons. Cerebral ischemia induces Dkk-1 expression, which contributes to neuronal cell death (12).

• References:

1. Krupnik, V.E. et al. (1999) Gene 238:301.  

2. Niehrs, C. (2006) Oncogene 25:7469. 

3. Bullock, C.M. et al. (2004) Mol. Pharmacol. 65:582. 

4. Mao, B. et al. (2001) Nature 411:321. 

5. Mao, B. et al. (2002) Nature 417:664.  

6. Kemp, C. et al. (2005) Dev. Dyn. 233:1064.

7. Adamska, M. et al. (2004) Dev. Biol. 272:134.

8. Li, J. et al. (2006) Bone 36:754.

9. Verani, R. et al. (2006) J. Neurochem. 101:242.

10. Pinzone, J.J. et al. (2009) Blood 113:517.

11. Morvan, F. et al. (2006) J. Bone Miner. Res. 21:934.

12. Cappuccio, I. et al. (2005) J. Neurosci. 25:2647.

• Long Name:

  Dickkopf-1

• Entrez Gene IDs:

  22943 (Human); 13380 (Mouse)

• Alternate Names:

  dickkopf (Xenopus laevis) homolog 1; dickkopf homolog 1 (Xenopus laevis); dickkopf related protein-1; Dickkopf-1; dickkopf-related protein 1; Dkk1; Dkk-1; hDkk-1; SKdickkopf-1 like