KPV

What is KPV?

KPV is a synthetic tripeptide: a chain of three amino acid residues with the sequence Lys-Pro-Val (lysine-proline-valine). The compound is known under CAS number 67727-97-3, with the molecular formula C₁₆H₃₀N₄O₄ (approx. 342.44 Da) and PubChem CID 125672. With three residues, KPV belongs to the shortest possible oligopeptides and thus forms the lower limit case of the peptide class.

The structure is chemically sharply defined: a basic lysine side chain with a free ε-amino group at the N-terminus, a central proline that restricts rotational freedom around the adjacent peptide bond, and a non-polar valine at the C-terminus. Consequently, the molecule carries both a positively charged and a non-polar part over only three positions. It is precisely this combination of short chain length, high polarity, and a cis/trans-isomerizable X-Pro bond that makes KPV extremely suitable for method development: short chains exhibit hardly any retention on standard reversed-phase columns and flush away close to the dead volume, making the compound a rigorous test case for column selection, ion-pairing reagents, and HILIC conditions. Furthermore, the fact that KPV contains no aromatic residue and therefore absorbs hardly at all above 220 nm makes it a useful model for detection problems involving weakly UV-active peptides.

Applications in a laboratory context

Within peptide chemistry and analytical work, KPV occurs in the following in vitro research areas, among others:

• Structure-activity relationship research regarding the separate contribution of the basic, rigidizing, and nonpolar positions to charge distribution, polarity, and retention behavior of very short chains.
• Peptide chemistry research towards solubility and conformational behavior of tripeptides, including the cis/trans ratio around the Lys-Pro bond monitored by NMR spectroscopy.
• Enzymatic stability studies in which it is determined how poorly X-Pro bonds are cleaved by most proteases under defined conditions, with the tripeptide as a simple reference point.
• Analytical method development and validation (HPLC, LC-MS, peptide mapping) in which retention, peak shape, and detection limit of low-molecular-weight polar peptides are optimized, with derivatization or mass spectrometric detection as an alternative to UV.

Specifications

Shape, handling and storage

The material is supplied as a freeze-dried powder (lyophilized powder), white to off-white in color, in a sealed glass vial with a rubber septum and an aluminium shrink cap. Short, highly polar peptides are distinctly hygroscopic; therefore, the vial remains closed in the original packaging until the sample is processed in the laboratory, because absorbed moisture weighs relatively heavily in the weight determination at a low molecular mass.

Store the sealed vial freeze-dried at 2–8 °C, in a dark and dry place. Furthermore, the usual laboratory precautions apply: work in a clean, dry environment, allow the vial to reach room temperature before opening to avoid condensation, and record the batch number and opening date for each vial in the lab log so that measurement series remain traceable afterwards.

Analytical quality

With a tripeptide, there is little room for uncertainty in the starting material: synthesis by-products and free amino acids come close to the main component in molecular mass and can coincide with the main peak in a chromatogram. Our KPV is supplied with a purity of ≥ 99%, determined by HPLC analysis in accordance with the corresponding certificate of analysis. The available certificates of analysis can be viewed on our website. lab results page.

Important disclaimer

We supply this product strictly for laboratory research and analytical work. It is not intended for diagnostic or therapeutic applications, and expressly not for use in humans or animals. This product is not a foodstuff, a supplement, a cosmetic product, or a registered medicinal product. By purchasing this product, the purchaser confirms that they are 18 years of age or older and will use the product exclusively within a controlled research or laboratory environment.