CST9L Protein, Human, Recombinant (hFc Tag)

Testatin is a member of the Cystatin family. Cystatins comprise genes that all show expression patterns that are strikingly restricted to reproductive tissue. Cystatins are a family of cysteine protease inhibitors with homology to chicken cystatin. There are typically about 115 amino acids in this family. They are largely acidic, contain four conserved cysteine residues known to form two disulfide bonds, may be glycosylated and/or phosphorylated, with similarity to fetuins, kininogens, stefins, histidine-rich glycoproteins and cystatin-related proteins. Testatin shows homology to family 2 cystatins, a group of broadly expressed small secretory proteins that are inhibitors of cysteine proteases in vitro but whose in vivo functions are unclear. It is expressed in germ cells and somatic cells in reproductive tissues. Testatin is considered a strong candidate for involvement in early testis development. Testatin expression is maintained in the adult Sertoli cell, and it can also be found in a small population of germ cells.

At Leading Biology, the biological activity of a recombinant protein is routinely measured using a bioassay, e.g. chemotaxis or cell proliferation assay, enzyme assay, or a functional ELISA. When a recombinant protein is an enzyme, specific activity is derived from an enzymatic assay. Each enzyme is tested for potency by cleavage of a substrate. We are in the process of updating the biological activity data. If you have any questions regarding this update, please feel free to contact our technical support team.

Lyophilized from sterile PBS, pH 7.4. Please contact us for any concerns or special requirements. Normally 5 % - 8 % trehalose, mannitol and 0.01% Tween 80 are added as protectants before lyophilization. Please refer to the specific buffer information in the hard copy of CoA.

The recombinant human CST9L/Fc chimera is a disulfide-linked homodimeric protein. The reduced monomer consists of 360 amino acids and has a calculated molecular mass of 41.3 kDa. In SDS-PAGE under reducing conditions, the apparent molecular mass of rhCST9L/Fc monomer is approximately 48 kDa.

In general, recombinant proteins are provided as lyophilized powder which are shipped at ambient temperature. Bulk packages of recombinant proteins are provided as frozen liquid. They are shipped out with blue ice unless customers require otherwise. Stable for 1 year at -20°C or below from date of shipment. For maximum recovery of product, centrifuge the original vial after thawing and opening the cap. For long-term storage, aliquot and store at -20°C or below. Avoid repeated freeze-thaw cycles.