Anti-Kallikrein-13 Rabbit Polyclonal Antibody

Frequently Asked Questions

What molecular weight should I expect for Kallikrein-13 on a Western blot?

Kallikrein-13 migrates at approximately 30-32 kDa on Western blot, corresponding to the mature processed form of the 277-amino acid protein. You may also detect the inactive zymogen at slightly higher molecular weight if your sample contains the pro-form. Because KLK13 is a secreted serine protease that undergoes proteolytic activation, the predominant band you observe depends on the activation state in your tissue or cell lysate. Conditioned media from KLK13-expressing cells typically shows the mature form; intracellular lysates may show both pro- and mature species.

Does this Kallikrein-13 antibody cross-react with other kallikrein family members?

The fifteen tissue kallikreins share substantial sequence homology, particularly in their catalytic domains, so cross-reactivity is a legitimate concern. This rabbit polyclonal was raised against human KLK13-specific epitopes and validated for specificity against human KLK13. We have not observed cross-reactivity with KLK2, KLK3, or KLK5 in our validation panels. However, we recommend running a negative control lysate from KLK13-null cells alongside your experimental samples, especially if other kallikreins are co-expressed in your tissue or cell model. Predicted cross-reactivity with mouse and dog orthologs reflects sequence conservation, not cross-family promiscuity.

What is the recommended starting dilution for Western blot with this KLK13 antibody?

Start at 1:1000 dilution in blocking buffer for Western blot, which works reliably with 20-30 µg total protein per lane from KLK13-expressing cell or tissue lysates. If you are working with low-abundance samples such as primary prostate epithelial cells or salivary gland homogenates, you may need to titrate up to 1:500. Conversely, if you are analyzing conditioned media or secreted fractions where KLK13 is concentrated, 1:2000 may suffice. Incubate overnight at 4°C for optimal signal. The 100 µg pack size provides approximately 100-200 blots at working dilution.

What tissues or cell lines are good positive controls for Kallikrein-13 expression?

Salivary gland tissue, prostate tissue, and certain breast carcinoma lines are well-documented KLK13-positive controls. Among cell lines, DU145 prostate carcinoma cells and some breast cancer lines (MCF-7 under specific hormonal conditions) express detectable KLK13, though expression levels vary with passage and culture conditions. For Western blot validation, recombinant human KLK13 protein serves as an unambiguous positive control and confirms antibody specificity at the expected molecular weight. If you are exploring KLK13 in a novel tissue context, include salivary gland lysate as a reference standard on the same blot to benchmark your signal.

Will this antibody work for mouse Kallikrein-13 in Western blot or IHC?

Mouse Klk13 shares approximately seventy percent sequence identity with human KLK13, and cross-reactivity is predicted based on epitope conservation. However, we have not formally validated this antibody against mouse tissue or lysates. If you are working with mouse models, we recommend testing the antibody at 1:500 to 1:1000 in parallel with a known human KLK13-positive control to assess signal specificity. Some researchers have successfully used human KLK antibodies in mouse prostate or salivary gland IHC, but empirical titration is essential. Consider including a blocking peptide or Klk13-knockout tissue as a negative control.

Should I use reducing or non-reducing conditions for KLK13 Western blot?

Kallikrein-13 contains disulfide bonds typical of serine proteases, but for Western blot it is typically run under reducing conditions with dithiothreitol or beta-mercaptoethanol. Reduction denatures the protein and improves epitope accessibility for most polyclonal antibodies, including this one. You should see a single predominant band at 30-32 kDa under reducing SDS-PAGE. Non-reducing conditions may preserve quaternary structure or disulfide-linked complexes but can also mask epitopes; we have not systematically tested this antibody under non-reducing conditions. If your experimental question requires native analysis, run a side-by-side comparison to confirm recognition.

How should I store this Kallikrein-13 antibody and what is the shelf life?

Store the antibody at -20°C in single-use aliquots to avoid repeated freeze-thaw cycles, which can reduce titer and increase background. The antibody is supplied in phosphate-buffered saline with glycerol as cryoprotectant; this formulation is stable for at least twelve months at -20°C and up to twenty-four months at -80°C. Once thawed, an aliquot can be held at 4°C for up to one month if sodium azide is added to 0.02 percent final concentration as preservative. Do not store diluted working solutions; prepare fresh dilutions in blocking buffer for each experiment to maintain optimal performance.

What sample preparation considerations are specific to detecting secreted Kallikrein-13?

Because KLK13 is a secreted serine protease, detection strategy depends on your sample source. For intracellular KLK13, lyse cells in the presence of protease inhibitors to prevent autocatalytic degradation and unintended substrate cleavage during extraction. For conditioned media or serum samples, concentrate the supernatant five- to ten-fold using centrifugal filters (10 kDa cutoff) to enrich secreted KLK13 before SDS-PAGE. Be aware that active KLK13 may degrade other proteins in your lysate if protease inhibitors are inadequate; include a serine protease inhibitor cocktail. For IHC, fixation in neutral-buffered formalin preserves KLK13 localization in secretory granules and extracellular matrix.