Secreted Frizzled Related Protein 3 (sFRP-3) was originally identified in bovine cartilage for its chondrogenic ability. Human, mouse, chick and Xenopus clones have also been isolated. sFRP-3 is often referred to as FRZB, other names include Fritz, Frzb1, and FRP-3. At the amino acid sequence level, sFRP-3 is highly conserved. The human protein shares 77% identity with Xenopus, 92% with mouse, and 94% with bovine proteins. Human sFRP-3 is strongly expressed in the developing appendicular skeleton, and cartilage of craniofacial bones. As determined by Northern blot of adult tissues, it is strongly detected in heart and placenta, as well as the brain, skeletal muscle, kidney and pancreas. The N-terminal portion of the protein shows 50% amino acid identity to the corresponding region of the Drosophila frizzled gene product, a receptor for Wg/Wnt signals. The similarity of sFRP-3 with frizzled proteins is restricted to the N-terminal cysteine-rich domain (CRD) that contains at least ten cysteine residues with highly conserved spacing between them. sFRP-3 was subsequently shown to be a soluble antagonist of Wnt signals. It lacks all transmembrane domains of frizzled proteins but retains the ability to bind Wnts. Ectopic expression of sFRP-3 mRNA has been shown to interfere with the induction of secondary axes in Xenopus embryos injected with Xwnt-8 mRNA (Hoang et al., 1996, J. Biol. Chem. 271:26131; Leyns et al., 1997, Cell 88:747; Wang et al.,1997, Cell 88:757; Mayr et al., 1997, Mech. Dev. 63:109; Rattner et al., 1997, PNAS 94:2859).
Source:A DNA sequence encoding the mature human sFRP-3 protein sequence (Leyns et al., 1997, Cell88:747) was fused to a 6X histidine tag at the carboxy-terminus. The fusion protein was expressed in a mouse myeloma cell line, NS0.
Molecular Mass:Based on N-terminal sequencing, the mature human sFRP-3 protein starts at Ala33 and has acalculated molecular mass of 35kD. As a result of glycosylation, the recombinant protein migrates as an ~38kD protein in SDS-PAGE under reducing conditions.
Endotoxin Level:≤ 1.0 EU per 1ug of the cytokine as determined by the LAL method.
Activity:Measured by its ability to interfere with the axis inducing activity of Xwnt-8 mRNA in early Xenopus embryos. In a population of embryos, addition of 1ng of rhsFRP protein per embryo resulted in 50-100% reduction in number of secondary axes produced by 10-20pg of Xwnt-8 mRNA.
Reconstitution:It is recommended that sterile PBS be added to the vial to prepare a working stock solution of no less than 50ug/ml. The carrier-free protein should be used immediately upon reconstitution to avoid losses in activity due to non-specific binding to the inside surface of the vial. For long term storage as a dilute solution, a carrier protein (e.g. 0.1% HSA or BSA) should be added to the vial.
Storage:Lyophilized samples are stable for greater than six months at -20°C to -70°C. Upon reconstitution, this cytokine, in the presence of carrier protein, can be stored under sterile conditions at 2°- 4°C for one month or at -20°C to -70°C for three months without detectable loss of activity. Avoid repeated freeze-thaw cycles.
仕様
Size：10ug
Source Antigen：Recombinant
Grade：Highly Purified
Purity：≥ 95%, as determined by SDS-PAGE and visualized by silver stain.
Form：Supplied as a lyophilized powder in PBS, pH 7.2.
