Prostamax

Prostamax is a synthetic tetrapeptide, Lys-Glu-Asp-Pro, from the Khavinson short-peptide bioregulator programme. The literature also uses the code KEDP, and one of Khavinson's own tables spells the name Prostomax.

The sequence is not inferred from vendor copy. The first claim of the European patent EP1353939B1 reads, in full, tetrapeptide Lys-Glu-Asp-Pro, and the specification describes the substance as made by classical solution-phase peptide synthesis. The NLM MeSH record for this name gives lysyl-glutamyl-aspartyl-proline and H-Lys-Glu-Asp-Pro-OH as entry terms, and Dzhokhadze and colleagues, in Georgian Medical News in 2012, use the name and the four residues together in their title and text.

Prostamax and Prostatilen are not the same class of material, and the patent itself is the clearest source on the distinction. Prostatilen is a polypeptide preparation obtained from animal prostate tissue; EP1353939B1 names it as the prototype the tetrapeptide was designed to replace, citing its complicated production, low yield of active substance and high variability in physicochemical properties. A defined four-residue synthetic peptide and an undefined tissue extract cannot share a specification, and vendor copy that blurs them is blurring two different kinds of material.

One caveat belongs on the page. What the synthetic tetrapeptide is, is established; what any particular product bearing this name contains is not, because several lines in this programme are sold as tissue-derived complexes rather than as synthetic peptides. The chemistry on this page describes the synthetic peptide of the patent, and incoming material should be checked against it rather than assumed to match.

Both termini are unmodified, and the lysine side chain carries a second free amine. The formula and mass are for the free acid, from PubChem CID 9848296 and stated independently in the patent, which also records a melting point of 142 degrees Celsius and a specific rotation of minus 69.2 degrees in water. The patent enumerates acetate, hydrochloride and oxalate among the salts it may be isolated as, without fixing a stoichiometry, so no salt-adjusted mass can be derived here. No CAS number is printed, because the number in circulation comes only from a supplier deposit on PubChem.

There is no tryptophan, tyrosine or phenylalanine, so there is no chromophore at 280 nm and the patent's chromatography runs at 220 nm. No receptor has been identified.

The published molecular work is chromatin-level and nucleic-acid-level rather than receptor-level. Dzhokhadze and colleagues measured sister-chromatid exchange frequency, silver-stained nucleolar organiser regions and pericentromeric C-band heterochromatin in cultured human lymphocytes. Meskhi and colleagues, in Biofizika in 2004, followed chromatin denaturation in the same cells by differential scanning calorimetry, interpreting the shifts as partial relaxation of the thirty-nanometre fibre. Solovyev and colleagues, in the International Journal of Biological Macromolecules in 2015, reported that the peptide alters the melting temperature of double-stranded DNA.