Human p21 ELISA Kit (ab214658)
Key features and details
- One-wash 90 minute protocol
- Sensitivity: 11 pg/ml
- Range: 62.5 pg/ml - 4000 pg/ml
- Sample type: Cell culture extracts, Tissue Lysate
- Detection method: Colorimetric
- Assay type: Sandwich (quantitative)
- Reacts with: Human
Product nameHuman p21 ELISA Kit
See all p21 kits
Intra-assay Sample n Mean SD CV% MCF7 lysates 5 4.2% Inter-assay Sample n Mean SD CV% MCF7 lysates 3 7.3%
Sample typeCell culture extracts, Tissue Lysate
Assay typeSandwich (quantitative)
Range62.5 pg/ml - 4000 pg/ml
Sample specific recovery Sample type Average % Range Cell culture media 120 115% - 129%
Assay time1h 30m
Assay durationOne step assay
Species reactivityReacts with: Human
Human p21 ELISA Kit (ab214658) is a single-wash 90 min sandwich ELISA designed for the quantitative measurement of p21 protein in tissue lysate and cell culture extracts. It uses our proprietary SimpleStep ELISA® technology. Quantitate Human p21 with 11 pg/ml sensitivity.
SimpleStep ELISA® technology employs capture antibodies conjugated to an affinity tag that is recognized by the monoclonal antibody used to coat our SimpleStep ELISA® plates. This approach to sandwich ELISA allows the formation of the antibody-analyte sandwich complex in a single step, significantly reducing assay time. See the SimpleStep ELISA® protocol summary in the image section for further details. Our SimpleStep ELISA® technology provides several benefits:
- Single-wash protocol reduces assay time to 90 minutes or less
- High sensitivity, specificity and reproducibility from superior antibodies
- Fully validated in biological samples
- 96-wells plate breakable into 12 x 8 wells strips
A 384-well SimpleStep ELISA® microplate (ab203359) is available to use as an alternative to the 96-well microplate provided with SimpleStep ELISA® kits.
p21 plays a critical role in the cellular response to DNA damage, and its overexpression results in cell cycle arrest. Upregulation of p21 mRNA and protein following ionizing radiation is dependent on p53 (TP53), and p21 mediates cell cycle arrest in response to the p53 checkpoint pathway. p21 binds to and inhibits cyclin-dependent kinase activity, preventing phosphorylation of critical cyclin-dependent kinase substrates and blocking cell cycle progression. p21 functions in the nuclear localization and assembly of cyclin D-CDK4 complex and promotes its kinase activity towards RB1. At higher stoichiometric ratios, p21 inhibits the kinase activity of the cyclin D-CDK4 complex.
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Storage instructionsStore at +4°C. Please refer to protocols.
Components 1 x 96 tests 10X Human p21 Capture Antibody 1 x 600µl 10X Human p21 Detector Antibody 1 x 600µl 10X Wash Buffer PT (ab206977) 1 x 20ml 50X Cell Extraction Enhancer Solution (ab193971) 1 x 1ml 5X Cell Extraction Buffer PTR (ab193970) 1 x 10ml Antibody Diluent 5BI 1 x 6ml Human p21 Lyophilized Recombinant Protein 2 vials Plate Seals 1 unit Sample Diluent NS (ab193972) 1 x 12ml SimpleStep Pre-Coated 96-Well Microplate (ab206978) 1 unit Stop Solution 1 x 12ml TMB Development Solution 1 x 12ml
FunctionMay be the important intermediate by which p53/TP53 mediates its role as an inhibitor of cellular proliferation in response to DNA damage. Binds to and inhibits cyclin-dependent kinase activity, preventing phosphorylation of critical cyclin-dependent kinase substrates and blocking cell cycle progression. Functions in the nuclear localization and assembly of cyclin D-CDK4 complex and promotes its kinase activity towards RB1. At higher stoichiometric ratios, inhibits the kinase activity of the cyclin D-CDK4 complex.
Tissue specificityExpressed in all adult human tissues, with 5-fold lower levels observed in the brain.
Sequence similaritiesBelongs to the CDI family.
DomainThe PIP-box K+4 motif mediates both the interaction with PCNA and the recuitment of the DCX(DTL) complex: while the PIP-box interacts with PCNA, the presence of the K+4 submotif, recruits the DCX(DTL) complex, leading to its ubiquitination.
The C-terminal is required for nuclear localization of the cyclin D-CDK4 complex.
modificationsPhosphorylation of Thr-145 by Akt or of Ser-146 by PKC impairs binding to PCNA. Phosphorylation at Ser-114 by GSK3-beta enhances ubiquitination by the DCX(DTL) complex.
Ubiquitinated by MKRN1; leading to polyubiquitination and 26S proteasome-dependent degradation. Ubiquitinated by the DCX(DTL) complex, also named CRL4(CDT2) complex, leading to its degradation during S phase or following UV irradiation. Ubiquitination by the DCX(DTL) complex is essential to control replication licensing and is PCNA-dependent: interacts with PCNA via its PIP-box, while the presence of the containing the 'K+4' motif in the PIP box, recruit the DCX(DTL) complex, leading to its degradation.
Cellular localizationCytoplasm. Nucleus.
- Information by UniProt
- CDK-interacting protein 1
- Entrez Gene: 1026 Human
- Omim: 116899 Human
- SwissProt: P38936 Human
- Unigene: 370771 Human
SimpleStep ELISA technology allows the formation of the antibody-antigen complex in one single step, reducing assay time to 90 minutes. Add samples or standards and antibody mix to wells all at once, incubate, wash, and add your final substrate. See protocol for a detailed step-by-step guide.
Background-subtracted data values (mean +/- SD) are graphed.
The concentrations of p21 were measured in duplicates in a two-fold dilution series and interpolated from the p21 standard curve and corrected for sample dilution. The interpolated dilution factor corrected values are plotted (mean +/- SD, n=2). The mean p21 concentration was determined to be 1,811 pg/mL in extract sample of MCF-7 cells treated for 18 hours with 1 mM camptothecin.
Interpolated concentrations of native p21 in human extract samples of HeLa cells, vehicle (DMSO)-treated MCF-7 cells and 18 hours 1 µM camptothecin-treated MCF-7 cells samples. The concentrations of p21 were measured in duplicates at 3 different dilutions, interpolated from the p21 standard curve. Note that Undiluted HeLa cell extract and Undiluted vehicle (DMSO)-treated MCF-7cell extract samples were at 32 g/mL. Note that Undiluted 18 hours 1 M camptothecin-treated MCF-7 cells samples were at 8 µg/mL. The interpolated, dilution factor-corrected values are graphed in pg of p21 per µg of total protein (mean +/- SD, n=2).
To learn more about the advantages of recombinant antibodies see here.
Datasheets and documents
ab214658 has been referenced in 2 publications.
- Gebarowski T et al. Effect of new olivacine derivatives on p53 protein level. Pharmacol Rep 72:214-224 (2020). PubMed: 32016852
- Ibrahim HS et al. One-pot synthesis of spiro(indoline-3,4'-pyrazolo[3,4-b]pyridine)-5'-carbonitriles as p53-MDM2 interaction inhibitors. Future Med Chem 10:2771-2789 (2018). PubMed: 30526032