p21 Waf1/Cip1 Blocking Peptide

Peptide is used to block p21 Waf1/Cip1 Rabbit mAb reactivity in immunohistochemistry protocols. The tumor suppressor protein p21 Waf1/ Cip1 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 (1). However, p21 may also enhance assembly and activity in complexes of CDK4 or CDK6 and cyclin D (2). 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 (3). 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 (4). Protein levels of p21 are downregulated through ubiquitination and proteasomal degradation (5). , Quality Control: The quality of the peptide was evaluated by reversed-phase HPLC and by mass spectrometry. The peptide blocks p21 Waf1/Cip1 Rabbit mAb signal in immunohistochemistry. , , Directions For Use: For immunohistochemistry, add twice the volume of peptide as volume of antibody used in 100ul total volume. Incubate for a minimum of 30 minutes prior to adding the entire volume to the slide. Recommended antibody dilutions can be found on the product data sheet. Storage and Stability: May be stored at 4°C for short-term only. For long-term storage, aliquot and store at -20°C. Aliquots are stable for at least 6 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.