KRT19 Human, His

Cytokeratin 19 (CK19), also known as Keratin 19 (K19), is a member of the keratin family, which are intermediate filament proteins responsible for the structural integrity of epithelial cells. CK19 is unique among cytokeratins as it is the smallest known acidic cytokeratin and is not paired with a basic cytokeratin in epithelial cells .

The human recombinant Cytokeratin 19 is produced in Escherichia coli and is a single, non-glycosylated polypeptide chain containing 423 amino acids, with a molecular mass of approximately 46.5 kDa . It is fused to a 23 amino acid His-Tag at the N-terminus, which facilitates its purification through affinity chromatography .

CK19 is specifically expressed in the periderm, the transiently superficial layer that envelopes the developing epidermis . It plays a crucial role in maintaining the structural integrity of epithelial cells and is involved in various cellular processes, including cell signaling, differentiation, and apoptosis .

Recombinant CK19 with a His-Tag is widely used in research for various applications:

• Immunohistochemistry (IHC): CK19 antibodies are used to identify epithelial cells in tissue sections, aiding in the diagnosis of epithelial malignancies .
• Western Blotting (WB): The His-Tag allows for easy detection and purification of CK19 in protein expression studies .
• Flow Cytometry: CK19 is used as a marker to distinguish different types of epithelial cells and to study their differentiation and maturation .

The recombinant CK19 protein is typically stored at 4°C for short-term use (2-4 weeks) and at -20°C for long-term storage. It is recommended to add a carrier protein, such as 0.1% human serum albumin (HSA) or bovine serum albumin (BSA), to prevent degradation during storage . The protein should be handled carefully to avoid freeze-thaw cycles, which can affect its stability and functionality .