PKI (5-24)

Product Name:PKI (5-24)

CAS No:99534-03-9

Purity:95%

Molar Mass:2222.38

Chemical Formula:C94H148N32O31

Storage:Store at -20 degrees Celsius

Sequence:TTYADFIASGRTGRRNAIHD

Target:PKA

Application:PKI (5-24) is a peptide fragment derived from the Protein Kinase Inhibitor (PKI), encompassing amino acids 5 to 24. This peptide is a potent and selective inhibitor of cyclic AMP-dependent protein kinase (PKA), which plays a crucial role in regulating cellular processes such as metabolism, gene expression, and cell proliferation. By binding to the catalytic subunit of PKA, PKI (5-24) effectively inhibits its kinase activity, making it a valuable tool in research studies focused on signal transduction pathways mediated by PKA. This peptide is commonly used to explore the mechanisms of PKA-related cellular processes and potential therapeutic targets in diseases linked to PKA dysregulation.

Current Research:

PKI (5-24) is a synthetic peptide that functions as a potent and selective inhibitor of cAMP-dependent protein kinase (PKA). Derived from the active domain of the naturally occurring heat-stable protein kinase inhibitor (PKI), this peptide corresponds to amino acid residues 5 through 24 of the native inhibitor. It exhibits a high affinity for PKA, with an inhibition constant (Kᵢ) of approximately 2.3 nM.

Mechanism of Action

PKI (5-24) operates as a competitive inhibitor by mimicking the substrate's binding motif. It binds to the catalytic subunit of PKA, effectively blocking substrate access and subsequent phosphorylation events. This binding is facilitated by a cluster of arginine residues within the peptide, which interact with the catalytic site of PKA, thereby inhibiting its kinase activity.

Research Applications

Due to its specificity and potency, PKI (5-24) is extensively utilized in biochemical and cellular studies to dissect PKA-mediated signaling pathways. It serves as a valuable tool for:

Investigating PKA Functions: By selectively inhibiting PKA, researchers can delineate its role in various cellular processes, including metabolism, gene expression, and cell proliferation.

Elucidating cAMP Signaling: PKI (5-24) aids in understanding how cAMP levels regulate PKA activity and downstream effects, providing insights into cellular responses to hormonal stimulation.

Developing Therapeutic Strategies: The peptide's inhibitory properties are instrumental in exploring potential treatments for diseases where dysregulated PKA activity is implicated, such as certain cancers and cardiovascular conditions.

Handling and Storage

PKI (5-24) is typically supplied as a lyophilized powder. For optimal stability, it should be stored at -20°C, protected from light and moisture. Upon reconstitution, aliquots should be prepared to avoid repeated freeze-thaw cycles, which can degrade the peptide.

Conclusion

As a highly effective and specific inhibitor of PKA, PKI (5-24) is an indispensable tool in molecular and cellular biology research. Its application facilitates a deeper understanding of PKA's role in health and disease, contributing to the advancement of targeted therapeutic interventions.

Reference:

Narayana, N., Cox, S., Shaltiel, S., Taylor, S. S., & Xuong, N. H. (1997). Crystal structure of a polyhistidine-tagged recombinant catalytic subunit of cAMP-dependent protein kinase complexed with the peptide inhibitor PKI (5? 24) and adenosine. Biochemistry, 36(15), 4438-4448.