KPV Peptide

KPV (Lys-Pro-Val) is a linear tripeptide composed of L-lysine, L-proline, and L-valine, corresponding to amino acid residues 11-13 at the C-terminus of alpha-melanocyte-stimulating hormone (alpha-MSH). With a molecular weight of approximately 342.4 Da and the molecular formula C16H31N5O4, KPV is one of the smallest peptides with documented immunomodulatory activity in published preclinical literature. Despite its minimal length, KPV retains a significant portion of the anti-inflammatory signaling activity attributed to the full-length 13-residue parent hormone.

Origin within the melanocortin system: Alpha-MSH is generated through proteolytic processing of proopiomelanocortin (POMC), a precursor polypeptide also giving rise to ACTH, beta-endorphin, and other melanocortin peptides. Alpha-MSH itself is classically associated with pigmentation, energy homeostasis, and immune regulation via melanocortin receptors (MC1R-MC5R). Structure-activity studies during the 1990s and 2000s systematically truncated alpha-MSH to identify the minimal sequence retaining anti-inflammatory activity. The C-terminal tripeptide KPV emerged as a remarkably active fragment, capable of recapitulating anti-inflammatory effects of the parent hormone in multiple in vitro and animal models without engaging classical pigmentary signaling.

Receptor-independent mechanism: A defining and unusual feature of KPV is that its anti-inflammatory activity appears to be largely independent of melanocortin receptor binding. Whereas alpha-MSH activates MC1R on melanocytes and immune cells, KPV does not require functional MC1R for many of its observed effects. Current mechanistic literature instead implicates intracellular targets, including interference with NF-κB nuclear translocation, modulation of MAPK signaling, and — in epithelial contexts — interaction with the PepT1 oligopeptide transporter, which can facilitate uptake into epithelial cells where the peptide subsequently down-regulates pro-inflammatory transcription programs.

Pharmacological characteristics: KPV's small size, neutral-to-basic charge (lysine contributes a positive charge at physiological pH), and proline-containing backbone confer several pharmacologically interesting properties for research: relative resistance to peptidase degradation compared with longer linear peptides, good aqueous solubility, and apparent capacity to cross epithelial barriers — features that have made KPV a model compound for studies of orally and topically delivered peptide anti-inflammatories.

Research applications: Published preclinical investigations have examined KPV in models of:

• Cutaneous inflammation, including UV-induced and contact hypersensitivity dermatitis
• Inflammatory bowel disease models (DSS-induced and TNBS-induced colitis in rodents)
• Allergic and innate immune responses involving mast cells, macrophages, and neutrophils
• Cytokine-driven epithelial inflammation in keratinocytes, intestinal epithelial cells, and respiratory epithelium

Relationship to other alpha-MSH fragments: KPV sits within a family of investigational alpha-MSH-derived peptides that includes the dipeptide KP and the full sequence alpha-MSH(1-13). Among these fragments, KPV has attracted particular attention because it combines compact size, synthetic tractability, and preserved anti-inflammatory activity, making it a convenient research tool for probing melanocortin-independent signaling pathways.

Regulatory status: KPV is supplied strictly as a reference compound for in vitro and preclinical laboratory research. It is not approved by the FDA or any other regulatory authority for human or veterinary use, and no statements on this page should be interpreted as medical advice or therapeutic claims. For laboratory research use only — not for human consumption.

Reconstitution: Add bacteriostatic water slowly along the vial wall. KPV is a tiny tripeptide (357 Da) that dissolves almost instantly. Solution should be clear and colorless.

Concentration: For a 5 mg vial, 1 mL BAC water = 5 mg/mL. For research protocols requiring mcg-level doses, further dilution with sterile saline is recommended for accurate measurement.

Oral administration: KPV is one of the rare peptides with oral bioactivity. It can be dissolved in water for oral research protocols targeting intestinal inflammation. The PepT1 transporter actively absorbs KPV across the intestinal epithelium.

Lyophilized powder: Long-term storage of KPV in lyophilized form is best performed at -20°C or colder in a sealed amber vial under desiccated conditions. Under these conditions, the tripeptide remains stable for 24+ months with negligible degradation detectable by analytical HPLC. Lyophilized aliquots may be transiently stored at 2-8°C for short periods (weeks) during active research use without measurable loss of purity, though repeated temperature cycling should be avoided to prevent moisture uptake.

Reconstituted solution: Once dissolved in bacteriostatic water, sterile water for injection, or phosphate-buffered saline (PBS), KPV solutions are typically stable at 2-8°C for approximately 21-28 days. For extended storage of reconstituted material, single-use aliquots may be flash-frozen at -20°C or -80°C; KPV tolerates a limited number of freeze-thaw cycles (generally <5) without significant loss of activity, but repeated cycling can promote aggregation in concentrated stocks.

Inherent stability advantages: KPV is one of the more chemically stable research peptides for several reasons:

• No oxidation-prone residues: KPV contains no methionine, cysteine, or tryptophan, eliminating the most common oxidative degradation pathways that complicate storage of larger peptides such as thymosin-beta-4 or BPC-157 fragments.
• Proline rigidity: The central proline imposes a constrained backbone conformation that resists enzymatic cleavage by many endo- and exopeptidases, and reduces the propensity for racemization at the adjacent lysine and valine residues.
• Small molecular size (~342 Da): Low molecular weight reduces aggregation risk and improves solubility profiles relative to longer peptides.
• No disulfide bonds or labile post-translational modifications requiring inert atmosphere handling.

Solubility: KPV is freely soluble in aqueous solvents owing to the basic lysine side chain. Concentrations up to several mg/mL are routinely achievable in water, saline, or PBS at neutral to slightly acidic pH. For research formulations requiring buffered systems, KPV remains stable across the physiological pH range (approximately pH 4-8); strongly alkaline conditions (pH >9) should be avoided as they can promote peptide bond hydrolysis over time.

Handling recommendations: Allow lyophilized vials to equilibrate to room temperature before opening to prevent condensation that introduces moisture into the powder. Reconstitute with gentle swirling rather than vigorous vortexing to minimize foaming. Protect stock solutions from prolonged light exposure as a general good-practice measure, although KPV does not contain strongly photolabile chromophores. Use sterile filtration (0.22 µm low-protein-binding membrane) when preparing solutions for cell culture applications. Maintain detailed records of reconstitution date, diluent, concentration, and freeze-thaw history for reproducibility.

Analytical confirmation: Researchers conducting extended studies are encouraged to verify peptide integrity by reverse-phase HPLC and mass spectrometry (expected monoisotopic mass [M+H]+ ≈ 343.2) periodically, particularly when comparing data across multiple reconstitution batches or after prolonged storage.