KPV 10mg

KPV (Lys-Pro-Val) is a synthetic tripeptide corresponding to the C-terminal fragment (residues 11-13) of alpha-melanocyte-stimulating hormone (alpha-MSH), with CAS number 67727-97-3. It has a molecular formula of C₁₅H₂₉N₃O₄ and a molecular weight of 315.41 Da. Unlike the parent alpha-MSH tridecapeptide, KPV lacks the pharmacophore core (His-Phe-Arg-Trp, residues 6-9) responsible for melanocortin receptor binding, indicating that its characterized activities operate through melanocortin receptor-independent mechanisms.

The primary molecular target of KPV identified in cell-based studies is the nuclear factor-kappa B (NF-kB) signaling pathway. KPV has been shown to inhibit NF-kB activation by preventing the phosphorylation and subsequent degradation of inhibitor of kappa B-alpha (IkB-alpha) in the cytoplasm. In unstimulated cells, NF-kB dimers (typically p65/p50 heterodimers) are sequestered in the cytoplasm by IkB proteins. Pro-inflammatory stimuli (TNF-alpha, IL-1beta, LPS) activate the IkB kinase (IKK) complex, which phosphorylates IkB-alpha at Ser32 and Ser36, targeting it for ubiquitination and proteasomal degradation. This releases NF-kB for nuclear translocation and transcription of inflammatory target genes. KPV interrupts this cascade upstream of IkB-alpha phosphorylation.

Additional characterized mechanisms include direct interaction with inflammatory signaling intermediates in the cytoplasm. Studies by Kannengiesser et al. (2008) demonstrated that KPV enters cells via the peptide transporter PepT1 (SLC15A1), a proton-coupled oligopeptide transporter expressed on epithelial cell membranes. Once internalized, KPV accesses intracellular signaling complexes directly, bypassing the requirement for cell-surface receptor engagement. This transport mechanism has been confirmed by competitive inhibition studies using the PepT1 substrate Gly-Sar.

Supplied as a lyophilized powder for in vitro research applications only. Not for human or veterinary use.

In Vitro Research Applications: KPV is employed in inflammatory signaling studies using multiple cell models. Luger et al. (2003) established that alpha-MSH C-terminal fragments including KPV suppress NF-kB activation in human dermal fibroblasts, monocytes, and keratinocyte cell lines stimulated with TNF-alpha or IL-1beta. Standard assay formats include NF-kB reporter gene assays (luciferase-based), IkB-alpha phosphorylation Western blots, and ELISA-based quantification of downstream cytokine production (IL-6, IL-8, TNF-alpha) following pro-inflammatory stimulation.

Signaling Pathway Studies: Key research applications include NF-kB nuclear translocation assays using immunofluorescence microscopy with anti-p65 antibodies, IKK kinase activity assays using immunoprecipitated IKK complexes, and phospho-IkB-alpha quantification by Western blot at multiple time points post-stimulation. The PepT1-dependent cellular uptake mechanism can be characterized using Caco-2 monolayer transport assays with competitive inhibitors and fluorescently labeled peptide analogs. Dose-response studies typically employ concentrations of 10 nM to 10 micromolar in cell culture systems.

Molecular Characterization: Identity verification is performed via ESI-MS or MALDI-TOF mass spectrometry (expected MW 315.41 Da). Purity is assessed by reversed-phase HPLC. The tripeptide sequence can be confirmed by tandem MS/MS fragmentation analysis. Stability in cell culture media can be evaluated by time-course HPLC to assess peptidase degradation kinetics under standard incubation conditions.

References

1. Luger TA, et al. (2003) New insights into the functions of alpha-MSH and related peptides in the immune system. Ann N Y Acad Sci, 994:133-140. PMID: 12851308
2. Kannengiesser K, et al. (2008) Melanocortin-derived tripeptide KPV has anti-inflammatory potential in murine models of inflammatory bowel disease. Inflamm Bowel Dis, 14(3):324-331. PMID: 18092347
3. Brzoska T, et al. (2008) Alpha-melanocyte-stimulating hormone and related tripeptides: biochemistry, antiinflammatory and protective effects in vitro and in vivo. Endocr Rev, 29(5):581-602. PMID: 18612058