• Product name

    Anti-Cathepsin K antibody [3F9]
    See all Cathepsin K primary antibodies
  • Description

    Mouse monoclonal [3F9] to Cathepsin K
  • Host species

  • Tested applications

    Suitable for: ELISA, WB, IP, IHC-P, Flow Cytmore details
  • Species reactivity

    Reacts with: Human
  • Immunogen

    Recombinant fusion protein, corresponding to amino acids 115-329 of Human Cathepsin K. The protein contains at the N-terninal end a His tag (6x) and 6 additional amino acid residues (MRGSHHHHHHGS).

  • Epitope

  • General notes

    This product was changed from ascites to tissue culture supernatant on 22nd December 2017. Please note that the dilutions may need to be adjusted accordingly. If you have any questions, please do not hesitate to contact our scientific support team



Our Abpromise guarantee covers the use of ab37259 in the following tested applications.

The application notes include recommended starting dilutions; optimal dilutions/concentrations should be determined by the end user.

Application Abreviews Notes
ELISA Use at an assay dependent concentration.
WB Use a concentration of 1 µg/ml. Detects a band of approximately 37, 40 kDa (predicted molecular weight: 37 kDa).
IP Use at an assay dependent concentration. PubMed: 24833013
IHC-P Use at an assay dependent concentration.
Flow Cyt Use 1µg for 106 cells.

ab170192 - Mouse monoclonal IgG2b, is suitable for use as an isotype control with this antibody.



  • Function

    Closely involved in osteoclastic bone resorption and may participate partially in the disorder of bone remodeling. Displays potent endoprotease activity against fibrinogen at acid pH. May play an important role in extracellular matrix degradation.
  • Tissue specificity

    Predominantly expressed in osteclasts (bones).
  • Involvement in disease

    Defects in CTSK are the cause of pycnodysostosis (PKND) [MIM:265800]. PKND is an autosomal recessive osteochondrodysplasia characterized by osteosclerosis and short stature.
  • Sequence similarities

    Belongs to the peptidase C1 family.
  • Cellular localization

  • Information by UniProt
  • Database links

  • Alternative names

    • Cathepsin K antibody
    • Cathepsin O antibody
    • Cathepsin O1 antibody
    • Cathepsin O2 antibody
    • Cathepsin X antibody
    • CATK_HUMAN antibody
    • CTS02 antibody
    • Ctsk antibody
    • CTSO antibody
    • CTSO1 antibody
    • CTSO2 antibody
    • MGC23107 antibody
    • PKND antibody
    • PYCD antibody
    see all


  • Bone from mouse foot (bone marrow with osteoclasts (positive). IHC-P image was obtained after deparaffinization, antigen retrieval with 0.1 M EDTA (6-8 min, 72 C), drying of slide before staining (10 min, 62 C), and subsequent staining with primary antibody (1/100) in 1% horse serum (1 h, 37 C).
  • Anti-Cathepsin K antibody [3F9] (ab37259) at 1 µg/ml + Human bone tumor tissue lysate - total protein (ab29359) at 10 µg

    Goat polyclonal Secondary Antibody to Mouse IgG - H&L (HRP), pre-adsorbed at 1/3000 dilution

    Developed using the ECL technique.

    Performed under reducing conditions.

    Predicted band size: 37 kDa
    Observed band size: 37 + 40 kDa
    why is the actual band size different from the predicted?
    Additional bands at: 26 kDa (possible cleavage fragment)

    Exposure time: 1 minute

    Cathepsin K contains a potential glycosylation site (SwissProt) which may explain its migration at a higher molecular weight than predicted, seen at 40 kDa. The band observed at 25 kDa could potentially be a cleaved form of Cathepsin K due to the presence of both a 15 amino acid signal prptide and a 99 amino acid propeptide. Cathepsin K in its mature form has an expected molecular weight of 25 kDa.
  • Overlay histogram showing U20S cells stained with ab37259 (red line). The cells were fixed with 80% methanol (5 min) and then permeabilized with 0.1% PBS-Tween for 20 min. The cells were then incubated in 1x PBS / 10% normal goat serum / 0.3M glycine to block non-specific protein-protein interactions. The cells were then incubated with the antibody (ab37259, 1µg/1x106 cells) for 30 min at 22ºC. The secondary antibody used was DyLight® 488 goat anti-mouse IgG (H+L) (ab96879) at 1/500 dilution for 30 min at 22ºC. Isotype control antibody (black line) was mouse IgG2b [PLPV219] (ab91366, 2µg/1x106 cells ) used under the same conditions. Acquisition of >5,000 events was performed. This antibody gave a positive signal in U20S cells fixed with 4% paraformaldehyde (10 min)/permeabilized in 0.1% PBS-Tween used under the same conditions.


This product has been referenced in:

  • Meng J  et al. Stachydrine prevents LPS-induced bone loss by inhibiting osteoclastogenesis via NF-?B and Akt signalling. J Cell Mol Med 23:6730-6743 (2019). Read more (PubMed: 31328430) »
  • Inamura K Translocation Renal Cell Carcinoma: An Update on Clinicopathological and Molecular Features. Cancers (Basel) 9:N/A (2017). IHC . Read more (PubMed: 28850056) »
See all 15 Publications for this product

Customer reviews and Q&As

1-2 of 2 Abreviews or Q&A


Grazie per la sua domanda. Vi rispondo in Inglese - se ha bisogno di una traduzione, mi faccia sapere per favore. Grazie!
Thank you for your inquiry.
The protocol on the datasheet is this protocol is from a customer who tested our antibody and provided his results and photo. The information about the drying is from him too. Unfortunately we do not know more.
As the tissue he used was bone as well, I would suspect that on bone tissue you can have special protocols (albeit decalcification is before fixation normally).
In any case, I can recommend you to follow your protocol which is established in your laboratory. I would recommend a normal heat induced antigen retrieval with boiling and only if your tissue is very sensitive, to do antigen retrieval overnight at 70°C. I would also recommend to test different antigen retrieval solutions at different pHs, as we recommend for all our antibodies.
I do also absolutely agree with you, that after rehydratation the sections should never dry out again, as this will impair the staining strongly.
The antibody incubation can be done at 37°C, however we recommend to incubate the antibody either 1 to 2 hours at room temperature or overnight at 4°C. This will be absolutely sufficient.
So in summary, I can recommend you to perform the immunostaining with this antibody as you would do normally. We do guarantee this antibody to work also with a classical IHC protocol.
I hope this information is helpful. Please do not hesitate to contact us again should you have any further question.

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Thank you for contacting us and your interest in our products.

I am sorry if the product datasheet has been misleading for your customer. The details provided with the image are to illustrate how this particular IHC staining experiment was performed. They are not intended as a recommendation of how IHC experiments have to be performed. For example the following reference have not used this method when staining human cancer tissue:

Birgersdotter A et al. Inflammation and tissue repair markers distinguish the nodular sclerosis and mixed cellularity subtypes of classical Hodgkin's lymphoma. Br J Cancer 101:1393-401 (2009). PubMed: 19773754

The information is provided as a guideline only and optimization is likely to be required depending on the tissue and protocol used by the customer. More information on how to optimize IHC experiments can be found from the following link:


I hope this information has been of help. If you require any further information please do not hesitate to contact us again.

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