SFRP3, Recombinant, Human (Secreted Frizzled Related Protein 3, FRZB, Fritz, Frzb1)

Secreted Frizzled Related Protein 3 (SFRP3) was originally identified in bovine cartilage for its chondrogenic ability. Human, mouse, chick and Xenopus clones have also been isolated. SFRP3 is often referred to as FRZB, other names include Fritz, Frzb1, and FRP-3. At the amino acid sequence level, SFRP3 is highly conserved. The human protein shares 77% identity with Xenopus, 92% with mouse and 94% with bovine proteins. Human SFRP3 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 SFRP3 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. SFRP3 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 SFRP3 mRNA has been shown to interfere with the induction of secondary axes in Xenopus embryos injected with Xwnt-8 mRNA. Recombinant protein corresponding to Ala33-Asn325 with a C-terminal 10-His tag from human SFRP3, expressed in NS0 cells, (Accession #AAB51298) , Molecular Mass: , Based on N-terminal sequencing, the mature human sFRP-3 protein starts at Ala33 and has a, calculated molecular mass of 35kD. As a result of glycosylation, the recombinant protein migrates as an ~38kD protein in SDS-PAGE under reducing conditions. Activity: Measured by its ability to inhibit proliferation in MC3T3-E1 mouse preosteoblastic cells. The ED50 is typically 1-4ug/ml. Storage and Stability: Lyophilized powder may be stored at -20°C. Stable for 6 months after receipt at -20°C. Reconstitute with sterile PBS, 0.1% HSA or BSA. Aliquot to avoid repeated freezing and thawing. Store at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.