KPV Tripeptide --- Research Product Overview

**Disclaimer:** This article is provided for educational and research purposes only. [KPV](/catalog/klow-blend) is not approved by the FDA for human use. Nothing in this article constitutes medical advice or a recommendation for self-administration. All references are to published preclinical and in-vitro research. Viking Labs sells research-grade material exclusively for in-vitro and laboratory animal research use.

Introduction

KPV is the C-terminal tripeptide fragment of alpha-melanocyte-stimulating hormone (alpha-MSH), corresponding to residues 11--13 of the parent thirteen-residue peptide. Its sequence (Lys-Pro-Val) was identified in the early 1990s as the minimal pharmacophore retaining the anti-inflammatory activity of the larger alpha-MSH molecule, while shedding the melanocortin-1 receptor (MC1R)-mediated pigmentary effects that complicate use of the parent peptide and analogs such as melanotan II. This dissociation of anti-inflammatory and pigmentary signaling has made KPV a tripeptide of sustained interest in inflammation and barrier-biology research, particularly in models of inflammatory bowel disease, atopic dermatitis, and ocular surface inflammation.

For broader context on the receptor family that KPV engages and the related peptides that act on it, see the melanocortin system overview and the comparison article on melanotan II and the melanocortin receptors.

Sequence and Physicochemical Properties

KPV is a linear tripeptide with the primary sequence H-Lys-Pro-Val-OH and a molecular weight of approximately 342.4 Da (free acid form; amidated forms differ by ~1 Da). The molecule carries a single positive charge from the lysine epsilon-amine at physiological pH, and the central proline introduces a kink that constrains conformation around the central peptide bond. KPV is highly water-soluble and stable in neutral aqueous buffer, though oxidative degradation of the lysine side chain has been reported on prolonged storage at room temperature.

Research-grade lyophilized KPV typically targets HPLC purity of >=98 percent, with mass-spectrometric confirmation of the parent ion at m/z 343.2 M+H]+. Endotoxin specifications for material destined for cell-culture work generally fall below 1 EU/mg. Investigators evaluating a Certificate of Analysis should confirm sequence identity by MS, purity by RP-HPLC, residual TFA content (a common counter-ion from solid-phase synthesis), and water content by Karl Fischer titration. The [guide to reading a peptide CoA covers each of these specifications in greater detail.

Mechanism of Action

KPV's anti-inflammatory activity has been studied across multiple cellular models. Three lines of evidence describe its mechanism:

Melanocortin receptor engagement (partial). KPV retains modest binding affinity for MC1R and MC3R but shows substantially reduced potency relative to the parent alpha-MSH. Receptor-independent pathways appear to dominate at the concentrations used in most in-vitro studies, distinguishing KPV from receptor-selective MC4R agonists.

NF-kB pathway suppression. The most consistent molecular signature of KPV treatment in cultured keratinocytes, endothelial cells, and intestinal epithelial cells is reduced nuclear translocation of the p65 subunit of NF-kB following pro-inflammatory stimulation with LPS, IL-1beta, or TNF-alpha. This translates into reduced transcription of downstream inflammatory mediators including IL-6, IL-8, and TNF-alpha itself, establishing a negative-feedback effect on the inflammatory cascade.

Direct intracellular delivery via PepT1. Studies in colonic epithelial cells have demonstrated that KPV is a substrate for the di/tripeptide transporter PepT1, allowing direct intracellular uptake and a mechanism by which oral or luminal exposure can produce intracellular anti-inflammatory effects. Dai et al. (2012) showed that PepT1-mediated uptake of KPV reduced expression of pro-inflammatory cytokines in cultured intestinal epithelial cells and ameliorated DSS-induced colitis in PepT1-expressing transgenic mice.

Preclinical Research Summary

The most extensively studied indication for KPV in preclinical research is inflammatory bowel disease. Multiple groups have reported reduced histological damage scores, lower myeloperoxidase activity, and improved barrier integrity in DSS- and TNBS-colitis models following oral or rectal KPV administration. Xiao et al. (2017) demonstrated that hyaluronic-acid-functionalized nanoparticles loaded with KPV achieved targeted delivery to inflamed colonic tissue and produced superior efficacy at substantially lower doses than free peptide.

In dermatological models, KPV has reduced contact-hypersensitivity responses and attenuated UV-induced cutaneous inflammation in murine models. Corneal and conjunctival inflammation models have also shown responsiveness to topical KPV. Importantly, no melanogenic activity has been reported at anti-inflammatory doses, which is the principal pharmacological argument for KPV over alpha-MSH itself.

Common Research Applications

In published research, KPV is most commonly used to:

• Probe NF-kB-dependent inflammatory signaling in epithelial and endothelial cell cultures.
• Serve as a comparator for newer alpha-MSH-related peptides such as KdPT (the all-D-amino-acid analog).
• Investigate PepT1-mediated peptide uptake mechanisms in intestinal epithelial models.
• Test colonic-targeted drug-delivery formulations using IBD animal models.

Comparator Peptides and Molecules

KPV occupies a distinctive niche within the alpha-MSH-related peptide family, and its research-tool value is best understood by direct comparison with adjacent molecules that share or contrast its mechanism.

KPV vs. parent alpha-MSH (1--13). Full-length alpha-MSH is the canonical melanocortin agonist with high-potency activity at MC1R, MC3R, MC4R, and MC5R. It is therefore inseparable from its pigmentary effects in any in-vivo model. KPV retains a substantial fraction of the parent's anti-inflammatory activity in NF-kB-driven assays at micromolar concentrations while showing essentially no melanogenic activity in B16 melanoma cells at the same concentrations --- the principal pharmacological argument for using KPV as an inflammation tool rather than alpha-MSH. The trade-off is potency: the parent peptide is typically active at nanomolar concentrations in receptor-binding assays, while KPV's anti-inflammatory effects appear at micromolar concentrations, consistent with weak partial agonism plus receptor-independent activity.

KPV vs. KdPT. KdPT (Lys-D-Pro-Thr) is the all-D-amino-acid C-terminal fragment of alpha-MSH (residues 11--13 in alternate numbering) and is the closest direct comparator to KPV. KdPT is more proteolytically stable than KPV due to D-amino-acid incorporation but shows a substantially weaker effect on PepT1-mediated uptake, since PepT1 is largely L-amino-acid-selective. Studies in cultured intestinal epithelial cells have generally found KPV to be more efficacious in PepT1-expressing systems and KdPT to be more efficacious in systems where PepT1-mediated delivery is not relevant.

KPV vs. melanotan II. Melanotan II is a cyclic non-selective melanocortin agonist with high MC1R potency; it is the comparator peptide most directly relevant to the pigmentary-vs-anti-inflammatory dissociation discussed above. See the melanotan II overview for full mechanism. The contrast with KPV illustrates why the C-terminal tripeptide is a cleaner research tool for inflammation work specifically.

KPV vs. antimicrobial-peptide-class molecules. For a different mode of barrier-and-inflammation modulation, see LL-37 antimicrobial peptide; LL-37 acts directly on bacterial membranes and on TLR-driven innate immunity rather than via melanocortin signaling.

Deeper Preclinical Breakdown

Three landmark studies define the modern KPV research literature.

Dalmasso et al. (2008), Gastroenterology. This pivotal paper formalized the PepT1-uptake-plus-NF-kB-inhibition mechanism. Using human intestinal epithelial cell lines (Caco2-BBE, HT29-Cl.19A) and Jurkat T cells stimulated with TNF-alpha and IL-1beta, the investigators showed that nanomolar KPV concentrations inhibited NF-kB luciferase reporter activation, p65 phosphorylation, and downstream IL-8 secretion. Crucially, blocking PepT1 with siRNA or with the competitive substrate Gly-Sar abolished KPV's anti-inflammatory effect in PepT1-positive cells, establishing transporter-mediated uptake as a non-receptor mechanism. In-vivo, oral KPV reduced histological damage and pro-inflammatory cytokine expression in DSS- and TNBS-induced murine colitis. Limitations: the in-vivo dose was empirically chosen rather than receptor-binding-derived, and translation to species lacking equivalent colonic PepT1 induction was not addressed.

Xiao et al. (2017), Molecular Therapy. Hyaluronic-acid-functionalized PLGA nanoparticles were engineered to encapsulate KPV and target inflamed colonic tissue via CD44 over-expression on inflamed colonic epithelium. The formulation achieved 12,000-fold lower effective dose vs. free KPV in DSS-colitis mice, with reduced systemic exposure and improved barrier-integrity recovery. The methodology --- combining peptide chemistry, polymer formulation, and CD44-targeted delivery --- is now a template for colonic-delivery research. Limitation: the formulation effect is partly orthogonal to peptide activity itself, and the study did not separate uptake-enhancement from receptor-pharmacology contributions.

Brzoska et al. (2008), Annals of the Rheumatic Diseases. A broader review of alpha-MSH-related peptides as anti-inflammatory and immunomodulating drugs placed KPV within a larger class including KdPT, MTII, and the parent alpha-MSH, with comparative data across keratinocyte, endothelial, and joint-tissue models. This paper remains a useful starting point for investigators new to the family.

Formulation Considerations

Research-grade KPV is supplied as a lyophilized white-to-off-white powder, typically in 5 mg or 10 mg sealed glass vials under inert atmosphere with silica desiccant. Lyophilization preserves the peptide against hydrolytic degradation indefinitely at -20 degrees C; the recommended diluents for reconstitution are sterile water (single-use) or bacteriostatic water containing 0.9 percent benzyl alcohol (multi-day use). KPV's lysine residue is mildly susceptible to oxidative modification in solution; aliquoting after reconstitution and minimizing exposure to atmospheric oxygen extends usable life. Common synthetic impurities include des-Lys and des-Val truncation products (visible as separate peaks on RP-HPLC), residual TFA from cleavage chemistry (controllable to <0.5 percent w/w with adequate post-cleavage washes), and racemization byproducts at the proline alpha-carbon (<1 percent in modern Fmoc SPPS). See the peptide solubility guide for buffer-compatibility notes specific to short basic peptides.

Research-Context Dosing Ranges

Published preclinical studies have used KPV across a wide concentration range depending on model and route. In-vitro NF-kB inhibition assays typically use 1--100 microM KPV in stimulated epithelial monolayers; receptor-binding studies on MC1R/MC3R have used nanomolar to low-micromolar concentrations to characterize partial-agonist behavior. In oral murine colitis models, Dalmasso et al. used 100 microg/mouse/day in drinking water across 7 days of DSS challenge. Topical dermatological models have used 0.1--1 percent w/v KPV in vehicle for cutaneous-inflammation suppression. These figures are reported as research-context anchors for in-vitro and animal-model design and should not be interpreted as human-use guidance.

Cross-References

For broader context within the Viking Labs research library, see the melanocortin system overview for the receptor family and signaling architecture, the antimicrobial peptide resistance review for an alternative class of barrier-and-immune modulators, and the BPC-157 product overview for a comparator gut-tropic research peptide. Handling and analytical protocols are covered in the peptide reconstitution guide and the peptide storage and stability reference.

Handling, Reconstitution, and Storage

Lyophilized KPV is stable at -20 degrees C for at least 24 months when sealed under inert atmosphere with desiccant. Reconstitution is typically performed in sterile water or bacteriostatic water (0.9 percent benzyl alcohol) at concentrations of 1--10 mg/mL for stock solutions; phosphate-buffered saline at neutral pH is appropriate for cell-culture work. Reconstituted solutions should be aliquoted to minimize freeze--thaw cycles and stored at -20 degrees C; working dilutions held at 4 degrees C should be used within 14--28 days.

Summary

KPV is a small, well-characterized tripeptide whose anti-inflammatory activity --- separable from alpha-MSH's pigmentary effects --- has supported a substantial preclinical literature in IBD, dermatology, and ocular inflammation models. As a research compound, its small size, water solubility, and PepT1 substrate behavior make it a convenient tool for probing NF-kB-dependent inflammation in epithelial systems.

*This article is provided for informational and research purposes only. Viking Labs does not sell products intended for human consumption.*