Anti-Serpin-B6 Rabbit Polyclonal Antibody

Frequently Asked Questions

What is the expected molecular weight for Serpin-B6 on Western blot?

Serpin-B6 runs at approximately 42-45 kDa on SDS-PAGE, corresponding to the 376-residue polypeptide. Some labs report a slightly higher apparent molecular weight depending on gel percentage and running conditions. Unlike some serpins, Serpin-B6 lacks a signal peptide and remains intracellular, so you should not see glycosylated forms. If you observe multiple bands, consider protease activity during lysis; include a cocktail with serine-protease inhibitors and keep samples cold. The recommended starting dilution for Western blot is 1:1000 in blocking buffer.

Does this Serpin-B6 antibody cross-react with mouse and rat samples?

The antibody is validated for human Serpin-B6 and shows predicted cross-reactivity with mouse and rat based on sequence homology in the immunogen region. Human and rodent Serpin-B6 share approximately 75-80 percent identity. We recommend empirical titration when working with rodent lysates, starting at 1:500 to 1:1000 for Western blot. If you are working with knockout or conditional models, include a Serpinb6-null control to confirm band specificity. Cross-reactivity with primate, dog, and pig samples is also predicted but requires validation in your hands.

Which tissues or cell lines express high levels of Serpin-B6 for positive controls?

Serpin-B6 is most abundant in brain tissue, particularly cortex and cerebellum, and in the inner ear epithelium. For cell-line controls, neuroblastoma lines such as SH-SY5Y or SK-N-SH typically show detectable expression. HEK293 and HeLa cells express lower but measurable levels. If you are validating the antibody or troubleshooting, consider using whole-brain lysate from mouse or human tissue as a positive control. Conversely, hematopoietic cells generally show lower expression, making them useful negative or low-expression comparators. Always run lysates in parallel to confirm band identity.

Can I use this antibody for immunofluorescence to visualize cytoplasmic Serpin-B6?

Yes, Triple Point Biologics antibodies are validated for immunofluorescence, and Serpin-B6 localizes to the cytoplasm, making IF a suitable application. Fix cells with four percent paraformaldehyde and permeabilize with 0.1-0.3 percent Triton X-100 or saponin. Start with a 1:100 to 1:200 dilution of the antibody in blocking buffer. You should observe diffuse cytoplasmic staining; punctate or nuclear signal may indicate nonspecific binding or lysosomal leakage. Include a no-primary control and, if available, a Serpin-B6 knockdown line to confirm specificity. Avoid methanol fixation, which can reduce epitope accessibility.

What sample preparation steps are critical when working with Serpin-B6?

Because Serpin-B6 is a protease inhibitor that binds serine proteases in the cytoplasm, rapid lysis and immediate cooling are essential to prevent degradation or complex formation. Use RIPA or NP-40 buffer supplemented with a protease-inhibitor cocktail, and keep samples on ice throughout. Avoid freeze-thaw cycles, which can cause aggregation or cleavage. For tissue samples, snap-freeze in liquid nitrogen and homogenize while still frozen. If studying Serpin-B6 interactions with target proteases, consider native lysis conditions and co-immunoprecipitation, but recognize that covalent serpin-protease complexes may alter the apparent molecular weight on Western blot.

Is Serpin-B6 expressed as multiple isoforms or splice variants?

The primary human Serpin-B6 transcript encodes a single 376-residue isoform. Minor splice variants have been deposited in sequence databases, but they are not well characterized and appear to be expressed at low levels or in restricted contexts. On Western blot, you should see a single dominant band around 42-45 kDa. If you detect higher-molecular-weight species, consider that Serpin-B6 can form SDS-stable covalent complexes with its target proteases, such as cathepsin G or thrombin, particularly in stressed or protease-rich samples. Running a reducing gel and including protease inhibitors during lysis will minimize these complexes.

How should I store this antibody and what is the expected shelf life?

Store the antibody at -20 degrees Celsius in small aliquots to avoid repeated freeze-thaw cycles, which can reduce titer and increase aggregation. Once thawed, an aliquot can be kept at four degrees Celsius for up to one month for routine use. Addition of 0.02-0.05 percent sodium azide or fifty percent glycerol can extend stability, though glycerol may require dilution adjustments. Triple Point Biologics polyclonal antibodies typically remain stable for at least two years when stored properly. If you observe declining signal or increased background over time, prepare a fresh aliquot and re-optimize dilution.

What controls should I include to validate Serpin-B6 antibody specificity?

Run a lane with brain or neuroblastoma lysate as a high-expression positive control and a lysate from a low-expression cell line such as Jurkat for comparison. If you have access to Serpin-B6 knockout or knockdown samples, these provide the strongest specificity control. Peptide competition with the immunogen can also block signal, though this requires the peptide sequence. For immunofluorescence, include a no-primary-antibody control and pre-absorption with recombinant Serpin-B6 if available. Always verify that the observed band matches the expected molecular weight of 42-45 kDa and that signal disappears upon gene silencing.