Validated using a knockout cell line

Recombinant Anti-Cdk8 antibody [EPR21005] - BSA and Azide free (ab239523)


  • Product name

    Anti-Cdk8 antibody [EPR21005] - BSA and Azide free
    See all Cdk8 primary antibodies
  • Description

    Rabbit monoclonal [EPR21005] to Cdk8 - BSA and Azide free
  • Host species

  • Tested applications

    Suitable for: WB, IPmore details
  • Species reactivity

    Reacts with: Human
  • Immunogen

    Recombinant fragment within Human Cdk8 aa 300 to the C-terminus. The exact sequence is proprietary.
    Database link: P49336

  • Positive control

    • WB: Wild-type HAP1, HCT 116 and SW480 whole cell lysates.
  • General notes

    Ab239523 is the carrier-free version of ab229192. This format is designed for use in antibody labeling, including fluorochromes, metal isotopes, oligonucleotides, enzymes.


    Our carrier-free formats are supplied in a buffer free of BSA, sodium azide and glycerol for higher conjugation efficiency.

    Use our conjugation kits  for antibody conjugates that are ready-to-use in as little as 20 minutes with <1 minute hands-on-time and 100% antibody recovery: available for fluorescent dyes, HRP, biotin and gold.

    ab239523 is compatible with the Maxpar® Antibody Labeling Kit from Fluidigm.

    Maxpar® is a trademark of Fluidigm Canada Inc.

    Our RabMAb® technology is a patented hybridoma-based technology for making rabbit monoclonal antibodies. For details on our patents, please refer to RabMab® patents.

    This product is a recombinant rabbit monoclonal antibody.



Our Abpromise guarantee covers the use of ab239523 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
WB Use at an assay dependent concentration. Detects a band of approximately 53 kDa (predicted molecular weight: 53 kDa).
IP Use at an assay dependent concentration.


  • Function

    Component of the Mediator complex, a coactivator involved in regulated gene transcription of nearly all RNA polymerase II-dependent genes. Mediator functions as a bridge to convey information from gene-specific regulatory proteins to the basal RNA polymerase II transcription machinery. Mediator is recruited to promoters by direct interactions with regulatory proteins and serves as a scaffold for the assembly of a functional preinitiation complex with RNA polymerase II and the general transcription factors. Phosphorylates the CTD (C-terminal domain) of the large subunit of RNA polymerase II (RNAp II), which may inhibit the formation of a transcription initiation complex. Phosphorylates CCNH leading to down-regulation of the TFIIH complex and transcriptional repression. Recruited through interaction with MAML1 to hyperphosphorylate the intracellular domain of NOTCH, leading to its degradation.
  • Sequence similarities

    Belongs to the protein kinase superfamily. CMGC Ser/Thr protein kinase family. CDC2/CDKX subfamily.
    Contains 1 protein kinase domain.
  • Cellular localization

  • Information by UniProt
  • Database links

  • Alternative names

    • cdk8 antibody
    • CDK8 protein kinase antibody
    • CDK8_HUMAN antibody
    • Cell Division Kinase 8 antibody
    • Cell division protein kinase 8 antibody
    • Cyclin Dependent kinase 8 antibody
    • Cyclin-dependent kinase 8 antibody
    • K35 antibody
    • Mediator complex subunit cdk8 antibody
    • Mediator of RNA polymerase II transcription subunit cdk8 antibody
    • Protein kinase K35 antibody
    see all


  • Cdk8 was immunoprecipitated from 0.35 mg of SW480 (human colorectal adenocarcinoma cell line) whole cell lysate with ab229192 at 1/30 dilution. Western blot was performed from the immunoprecipitate using ab229192 at 1/1000 dilution. VeriBlot for IP Detection Reagent (HRP) (ab131366) was used for detection at 1/10,000 dilution.

    Lane 1: SW480 whole cell lysate 10 μg (Input).
    Lane 2: ab229192 IP in SW480 whole cell lysate.
    Lane 3: Rabbit monoclonal IgG (ab172730) instead of ab229192 in SW480 whole cell lysate.

    Blocking and dilution buffer and concentration: 5% NFDM/TBST.
    Exposure time: 3 minutes.

    This data was developed using the same antibody clone in a different buffer formulation containing PBS, BSA, glycerol, and sodium azide (ab229192).

  • All lanes : Anti-Cdk8 antibody [EPR21005] (ab229192) at 1/1000 dilution

    Lane 1 : Wild-type HAP1 whole cell lysate at 20 µg
    Lane 2 : Cdk8 knockout HAP1 whole cell lysate at 20 µg
    Lane 3 : HCT 116 (human colorectal carcinoma cell line) whole cell lysate at 10 µg
    Lane 4 : SW480 (Human colorectal adenocarcinoma cell line) whole cell lysate at 10 µg

    All lanes : Goat Anti-Rabbit IgG H&L (HRP) (ab97051) at 1/100000 dilution

    Predicted band size: 53 kDa

    Exposure time: 48 seconds

    Blocking and dilution buffer: 5% NFDM/TBST.

    ab229192 was shown to specifically react with Cdk8 in wild-type HAP1 cells as signal was lost in Cdk8 knockout cells.

    Wild-type and Cdk8 knockout samples were subjected to SDS-PAGE. ab229192 and ab181602 (Rabbit anti-GAPDH loading control) were incubated 1 hour at room temperature at 1/1000 dilution and 1/200,000 dilution respectively. Blots were developed with Goat Anti-Rabbit IgG, (H+L), Peroxidase conjugated (ab97051) secondary antibody at 1/100,000 dilution for 1 hour at room temperature before imaging. The blot was developed on a BIO-RAD® ChemiDoc™ MP instrument using the ECL technique.

    This data was developed using the same antibody clone in a different buffer formulation containing PBS, BSA, glycerol, and sodium azide (ab229192).


ab239523 has not yet been referenced specifically in any publications.

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