Catalog # CM5131

p21/CIP1/WAF1 Antibody

Mouse Monoclonal

Application / Dilution

Size 100 μl

Species Reactivity Hu

MW 21 kDa

Isotype IgG2a



The tumor suppressor protein p21/CIP1/WAF1 acts as an inhibitor of cell cycle progression. It functions in stoichiometric relationships forming heterotrimeric complexes with cyclins and cyclin-dependent kinases. In association with CDK2 complexes, it serves to inhibit kinase activity and block progression through G1/S. However, p21 may also enhance assembly and activity in complexes of CDK4 or CDK6 and cyclin D. The carboxy-terminal region of p21 is sufficient to bind and inhibit PCNA, a subunit of DNA polymerase, and may coordinate DNA replication with cell cycle progression. Upon UV damage or during cell cycle stages when cdc2/cyclin B or CDK2/cyclin A are active, p53 is phosphorylated and upregulates p21 transcription via a p53-responsive element. Protein levels of p21 are downregulated through ubiquitination and proteasomal degradation.


Sheaff, R.J. et al. (2000) Cell 5:403.
Cheng, J. et al. (1999) EMBO J. 18:1571.
Flores-Rozas, H. et al. (1994) PNAS, USA. 91:8655.

Western blot analysis of p21 expression in human endothelial cells (lanes 1 & 2). The blots were probed with mouse monoclonal anti-p21 at 1:250 (lane 1) and 1:1000 (lane 2).

Clone M513 was generated from a full length recombinant human p21 protein. The antibody detects human p21.

*For more information, see UniProt Accession P38936
Mouse monoclonal antibody purified with protein A chromatography is supplied in 100µl phosphate-buffered saline, 50% glycerol, 1 mg/ml BSA, and 0.05% sodium azide. Store at –20°C. Stable for 1 year.

The products are are safely shipped at ambient temperature for both domestic and international shipments. Each product is guaranteed to match the specifications as indicated on the corresponding technical data sheet. Please store at -20C upon arrival for long term storage.

The antibody detects a 21 kDa* protein corresponding to the apparent molecular mass of p21 on SDS-PAGE immunoblots of human endothelial cells (HUVEC), HeLa cells, and Fibroblasts. The antibody is also useful for immunoprecipitation and immunofluorescent labeling in human cells.

*All molecular weights (MW) are confirmed by comparison to Bio-Rad Rainbow Markers and to western blot mobilities of known proteins with similar MW.

This kit contains: