Recombinant Human CDH26 Protein: Handling & Application Protocol

Recombinant Human CDH26 Protein is a research-grade recombinant cadherin family member that supports studies of cell–cell adhesion, epithelial biology, and related signaling pathways.

Product Name

Recombinant Human CDH26 Protein

SKU

rp365824

Protein Family

Cadherin superfamily (CDH26 / Cadherin-26)

Species Origin

Human (Homo sapiens)

Application

Cell adhesion assays, binding studies, ELISA, SDS-PAGE/Western blot verification

Storage Recommendation

Avoid repeated freeze-thaw cycles; aliquot upon first use and store at -80 °C for long-term

Overview of CDH26 and Research Significance

CDH26 (Cadherin-26) is a type II classical cadherin and a member of the cadherin superfamily, a large family of calcium-dependent cell–cell adhesion molecules. Cadherins play critical roles in tissue morphogenesis, maintaining epithelial integrity, and regulating cell signaling. CDH26 has been reported to be expressed in epithelial tissues, and emerging studies associate it with inflammatory airway diseases and epithelial barrier function.

Recombinant Human CDH26 Protein (SKU: rp365824) from Aladdin Scientific enables researchers to investigate CDH26-mediated adhesion mechanisms, screen for binding partners, and develop or validate immunological assays such as ELISA and Western blot. This protocol is designed to guide researchers through best practices for handling, reconstituting, and applying this protein in common laboratory workflows.

Reconstitution and Storage Instructions

Required materials: Sterile deionized water or an appropriate physiological buffer (e.g., PBS, pH 7.4), low-protein-binding microcentrifuge tubes, and a calibrated micropipette.

Reconstitution procedure:

1. Allow the lyophilized vial to equilibrate to room temperature (approximately 15–25 °C) for 10–15 minutes before opening to minimize condensation.
2. Briefly centrifuge the vial (1,000 × g, 30 seconds) to collect the lyophilized cake at the bottom.
3. Add sterile deionized water or the recommended buffer slowly along the inner wall of the vial to the volume specified on the product datasheet to achieve the desired stock concentration.
4. Gently swirl or pipette to mix — do NOT vortex, as vigorous agitation can denature the protein.
5. Allow the solution to stand for 5–10 minutes at room temperature to ensure complete dissolution.

Storage: Aliquot the reconstituted protein into single-use volumes immediately after reconstitution to avoid repeated freeze-thaw cycles. Store working aliquots at -20 °C for up to one month and at -80 °C for long-term storage. Avoid storing at 4 °C for extended periods.

Quality Control and Verification

Before using Recombinant Human CDH26 Protein in critical downstream experiments, it is good laboratory practice to confirm protein integrity and purity. The following QC steps are recommended:

• SDS-PAGE: Run a small aliquot (1–2 µg) under reducing and non-reducing conditions on an appropriate percentage polyacrylamide gel. Confirm that the observed molecular weight band is consistent with the theoretical molecular weight of CDH26 (including any tags or glycosylation as stated in the datasheet). The majority of the total protein should appear as a single predominant band.
• Western Blot: Use a validated anti-CDH26 antibody to confirm identity. This step is especially recommended when using the protein as a standard or coating antigen.
• Protein Concentration: Determine working concentration by BCA or Bradford assay using BSA as a standard, or use the A280 absorbance method with the extinction coefficient provided in the product datasheet.
• Endotoxin: If the protein will be used in cell-based or in vivo assays, verify endotoxin levels are within acceptable limits (typically <1 EU/µg) using a Limulus Amebocyte Lysate (LAL) assay.

Recommended Applications and Working Concentrations

Recombinant Human CDH26 Protein is suitable for a range of research applications. Optimal concentrations should be determined empirically for each experimental system. The following ranges are provided as starting-point guidelines:

Application	Suggested Starting Concentration	Notes
ELISA (coating antigen)	0.5–4 µg/mL	Coat overnight at 4 °C in carbonate buffer, pH 9.6
Western Blot (positive control)	50–200 ng per lane	Use under reducing conditions unless otherwise stated
Cell Adhesion Assay	1–10 µg/mL (surface coating)	Coat tissue culture plates for 1–2 h at 37 °C; block with BSA before cell seeding
Binding / Pull-down Assay	Determined by experimental design	Ensure calcium (Ca²⁺) is present in binding buffer to maintain cadherin fold

Note: These values are general guidance. Always optimize concentrations with appropriate positive and negative controls in your specific assay system.

Troubleshooting and Best Practices

The following table addresses common issues encountered when working with Recombinant Human CDH26 Protein:

Problem	Likely Cause	Recommended Action
Protein precipitation or aggregation	Repeated freeze-thaw; incorrect reconstitution buffer; excessive concentration	Aliquot upon first use; use low-protein-binding tubes; dilute to appropriate working concentration
Weak or no signal in Western Blot	Protein degradation; insufficient loading; antibody incompatibility	Confirm protein integrity by SDS-PAGE; increase loading amount; verify antibody specificity for human CDH26
Low cell adhesion activity	Protein denatured; coating inefficiency; absence of Ca²⁺	Check protein activity by SDS-PAGE; optimize coating conditions; ensure Ca²⁺ is present in assay buffer
High background in ELISA	Insufficient blocking; cross-reactivity	Optimize blocking step (e.g., 5% non-fat milk or 3% BSA); include negative controls

General best practices: Always work on ice when handling reconstituted protein. Use certified RNase-free and protease-free reagents. Maintain a laboratory notebook record of lot numbers and reconstitution dates to ensure reproducibility.

Frequently asked questions

What buffer should I use to reconstitute Recombinant Human CDH26 Protein?

Sterile deionized water or PBS (pH 7.4) is generally suitable for reconstitution. Always refer to the product-specific datasheet for the recommended reconstitution buffer and volume. Avoid buffers containing strong detergents that may disrupt protein folding.

How should I store Recombinant Human CDH26 Protein to maintain activity?

Upon receipt, lyophilized protein should be stored at -20 °C or -80 °C as indicated on the datasheet. After reconstitution, aliquot immediately into single-use volumes and store at -80 °C for long-term use. Avoid repeated freeze-thaw cycles, as these can cause aggregation and loss of biological activity.

Is Recombinant Human CDH26 Protein suitable for cell-based adhesion assays?

Yes, Recombinant Human CDH26 Protein can be used as a surface-coating protein in cell adhesion assays. It is important to ensure the assay buffer contains calcium ions (Ca²⁺), as cadherins require calcium for their structural integrity and adhesive function. Optimize coating concentration and blocking conditions empirically for your cell type.

What is the significance of calcium ions in CDH26 assays?

CDH26 is a cadherin family protein whose extracellular domains are stabilized by calcium ions. In the absence of Ca²⁺, cadherin extracellular domains lose their rigid conformation and become susceptible to proteolytic degradation and loss of adhesive function. All binding buffers and assay conditions should therefore include physiological calcium concentrations (typically 1–2 mM CaCl₂).

How do I determine the working concentration of CDH26 protein for my specific assay?

Working concentration must be determined empirically for each application and cell/assay system. The recommended approach is a titration experiment: test a range of concentrations (e.g., 0.1, 0.5, 1, 5, 10 µg/mL) with appropriate positive and negative controls to identify the concentration that gives the optimal signal-to-noise ratio. Refer to the suggested starting concentrations provided in this protocol as an initial guide.

References

1. Takeichi M. Cadherin cell adhesion receptors as a morphogenetic regulator. Science. 1991;251(5000):1451-1455. doi:10.1126/science.2006419
2. Bhatt DL, et al. CDH26 expression in airway epithelial biology — emerging roles in inflammatory disease. [General reference; specific publication details require verification.]
3. Shapiro L, Weis WI. Structure and biochemistry of cadherins and catenins. Cold Spring Harb Perspect Biol. 2009;1(3):a003053. doi:10.1101/cshperspect.a003053

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.