Recombinant Human Cathepsin L Protein (His Tag)

Beta LifeScience SKU/CAT #: BLPSN-0605

Recombinant Human Cathepsin L Protein (His Tag)

Beta LifeScience SKU/CAT #: BLPSN-0605
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Product Overview

Tag His
Host Species Human
Accession NP_001903.1
Synonym CATL, CTSL1, MEP
Background Cathepsin L is a lysosomal cysteine protease that plays a major role in intracellular protein catabolism, and is potent in degrading collagen, laminin, elastin, as well as alpha-1 protease inhibitor and other structural proteins of basement membranes. It is secreted by liver flukes at all stages of their development in the mammalian host, are believed to play important roles in facilitating parasite migration (tissue degradation), feeding and immuno-evasion. Like many proteases, Cathepsin L is synthesized as an inactive preproenzyme, and cleavage of the 96-residue proregion is necessary to generate the fully active 221-residue mature enzyme. Studies have demonstrated that cleavage of the proregion occur autocatalytically under acidic conditions. The enzyme takes part in nutrient acquisition by catabolizing host proteins to absorbable peptides, facilitates the migration of the parasite through the host intestine and liver by cleaving interstitial matrix proteins such as fibronectin, laminin and native collagen and is implicated in the inactivation of host immune defenses by cleaving immunoglobulins. Recently, Cathepsin L has been shown to suppress Th1 immune response in infected laboratory animals making them susceptible to concurrent bacterial infections. Cathepsin L is synthesized in large amounts and secreted by many malignantly transformed cells, and induced by growth factors and tumor promoters. In addition to its role in protein degradation, evidence has accumulated for the participation of Cathepsin L in various physiological and pathological processes, such as tumor invasion and metastasis, bone resorption, spermatogenesis, and arthritis. Accordingly, Cathepsin L may prove useful as a diagnostic or prognostic marker of human tumor malignancy.
Description A DNA sequence encoding the pro form of human Cathepsin-L1 (NP_001903.1) (Met 1-Val 333) was expressed, fused with a His tag at the C-terminus.
Source HEK293
Predicted N Terminal Thr 18
AA Sequence Met 1-Val 333
Molecular Weight The recombinant human CTSL1 consists of 327 a.a. and has a predicted molecular mass of 37.3 kDa. In SDS-PAGE under reducing conditions, the apparent molecular mass of recombinant human CTSL1 is approximately 37 kDa.
Purity >90% as determined by SDS-PAGE
Endotoxin < 1.0 EU per μg of the protein as determined by the LAL method
Bioactivity Measured by its binding ability in a functional ELISA. Immobilized human CD74 at 5 ug/ml (100 ul/well) can bind biotinylated human CTSL1 with a linear range of 3.2-400 ng/ml.
Formulation Lyophilized from sterile 50 mM NaAc, 100 mM NaCl, pH 7.5..
Stability The recombinant proteins are stable for up to 1 year from date of receipt at -70°C.
Usage For Research Use Only
Storage Store the protein under sterile conditions at -20°C to -80°C. It is recommended that the protein be aliquoted for optimal storage. Avoid repeated freeze-thaw cycles.


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Proteins are sensitive to heat, and freeze-drying can preserve the activity of the majority of proteins. It improves protein stability, extends storage time, and reduces shipping costs. However, freeze-drying can also lead to the loss of the active portion of the protein and cause aggregation and denaturation issues. Nonetheless, these adverse effects can be minimized by incorporating protective agents such as stabilizers, additives, and excipients, and by carefully controlling various lyophilization conditions.

Commonly used protectant include saccharides, polyols, polymers, surfactants, some proteins and amino acids etc. We usually add 8% (mass ratio by volume) of trehalose and mannitol as lyoprotectant. Trehalose can significantly prevent the alter of the protein secondary structure, the extension and aggregation of proteins during freeze-drying process; mannitol is also a universal applied protectant and fillers, which can reduce the aggregation of certain proteins after lyophilization.

Our protein products do not contain carrier protein or other additives (such as bovine serum albumin (BSA), human serum albumin (HSA) and sucrose, etc., and when lyophilized with the solution with the lowest salt content, they often cannot form A white grid structure, but a small amount of protein is deposited in the tube during the freeze-drying process, forming a thin or invisible transparent protein layer.

Reminder: Before opening the tube cap, we recommend that you quickly centrifuge for 20-30 seconds in a small centrifuge, so that the protein attached to the tube cap or the tube wall can be aggregated at the bottom of the tube. Our quality control procedures ensure that each tube contains the correct amount of protein, and although sometimes you can't see the protein powder, the amount of protein in the tube is still very precise.

To learn more about how to properly dissolve the lyophilized recombinant protein, please visit Lyophilization FAQs.

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