Recombinant Human CST3 protein(Ser27-Ala146), His-tagged

• Cat.No.: CST3-3172H
• Product Overview: Recombinant Human Cystatin-C (NP_000090.1) (Ser 27-Ala 146) was expressed in HEK293 with a C-terminal polyhistidine tag.

Specification

• Species: Human
• Source: HEK293
• Tag: His
• Protein Length: 1-146 a.a.
• Form: Lyophilized from sterile PBS, pH 7.4. Normally 5 % - 8 % trehalose, mannitol and 0.01% Tween80 are added as protectants before lyophilization.
• Bio-activity: Measured by its ability to inhibit papain cleavage of a fluorogenic peptide substrate Z-FR-AMC. The IC50 value is < 12 nM.
• Molecular Mass: The mature recombinant human Cystatin-C consists of 131 amino acids and predicts a molecular mass of 14.8 kDa. The rh Cystatin-C migrates as approximately 17 kDa band in SDS-PAGE as a result of glycosylation.
• Endotoxin: < 1.0 EU per μg of the protein as determined by the LAL method
• Purity: > 95 % as determined by SDS-PAGE
• Storage: Samples are stable for up to twelve months from date of receipt at -20°C to -80°C. Store it 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.
• Reconstitution: It is recommended that sterile water be added to the vial to prepare a stock solution of 0.2 ug/ul. Centrifuge the vial at 4°C before opening to recover the entire contents.

Gene Information

• Gene Name: CST3 cystatin C [ Homo sapiens ]
• Official Symbol: CST3
• Synonyms: CST3; cystatin C; cystatin C (amyloid angiopathy and cerebral hemorrhage); cystatin-C; cystatin 3; cystatin-3; gamma-trace; post-gamma-globulin; bA218C14.4 (cystatin C); neuroendocrine basic polypeptide; ARMD11; MGC117328
• Gene ID: 1471
• mRNA Refseq: NM_000099
• Protein Refseq: NP_000090
• MIM: 604312
• UniProt ID: P01034

Case Study

Case 1: Jurczak P, et al. Chembiochem. 2024

Human cystatin C (hCC) inhibits cysteine proteinases but can form toxic amyloids in disease. It’s active outside cells and inactive inside, yet how it crosses into cells wasn't clear. This study used HeLa cells and found that hCC enters mainly through endocytosis, and its form—monomer or dimer—doesn't significantly affect this. This insight helps to better understand hCC's roles inside and outside the cell.

Fig1. Chromatograms representing the oligomeric states of hCC WT (monomer) and its three mutants hCC V57G (monomer), hCC L68V (monomer), and hCC V57P (dimer).

Fig2. Live cell imaging of hCC penetration into HeLa cells.

Case 2: Modenbach JM, et al. Nat Commun. 2025

Acute pancreatitis (AP) is when the pancreas digests itself due to early activation of trypsinogen by CTSB. Normally, CTSL degrades trypsin to prevent this, while CST3 inhibits both CTSB and CTSL. In CST3-deficient mice, CTSB activity increases, worsening AP. When CST3 is cleaved by trypsin, it fails to inhibit CTSB and instead enhances its activity, intensifying the enzyme cascade in AP.

Fig1. Measurement of CTSB activity.

Fig2. SDS-PAGE analysis of cystatin C wild-type and mutants where several possible cleavage sites were substituted with alanine residues.

Application

Recombinant CST3 protein is a key player in medical research, especially for its role in inhibiting cysteine proteases like cathepsin B and L. This function is crucial when looking into disorders where these enzymes run rampant, such as neurodegenerative diseases, some cancers, and inflammatory conditions. By exploring CST3, researchers are hopeful about finding ways to control these enzymes, which could lead to breakthroughs in slowing down disease progression. In industrial settings, CST3’s ability to curb unwanted enzyme activity aids in processes like fermentation, where maintaining protein integrity is vital. The recombinant form of CST3 allows it to be produced on a large scale, giving industries a dependable tool for managing proteins. In the realm of scientific research, recombinant CST3 helps dissect protein interactions and cellular mechanisms. It provides insights into protease-driven processes and could lead to novel solutions for various biological challenges. Overall, CST3 is an essential element for advancing our understanding of complex biological systems, with promising implications for health and industry advancements.

Fig1. Supposed mechanisms underlying the dual opposing effects of Cystatin C (Cyst C) on urogenital malignancy progression. (Li Ding, 2022)