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Research area

Peptide Fragments: UK Research Peptides

For research use only. Not for human or veterinary use. Sold strictly for in-vitro laboratory research; not for diagnosis or treatment.

This research area gathers linear synthetic peptides and co-lyophilised blends of them. The single peptides are chains of standard amino acids without cyclisation or lipidation, so their identity rests on residue count, sequence and molecular formula rather than on side-chain chemistry. BPC-157 is a pentadecapeptide, Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val, with the formula C62H98N16O22 and a molecular weight of 1419.53 g/mol; four of its fifteen residues are proline. TB-500 corresponds to thymosin β4, a single chain of forty-three residues (C212H350N56O78S). A blend has no single formula or CAS number. Linear peptides of this kind are usually characterised by reversed-phase HPLC together with mass spectrometry against the expected mass. Each product in this area is supplied as a lyophilised solid in a sealed vial.

Compounds in this research area

Structural features

The single peptides in this research area are linear chains without cyclisation or lipidation, so their identity rests on residue count, sequence and molecular formula. BPC-157 shows the pattern clearly. Its fifteen residues, H-Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val-OH, are all standard amino acids, with a free amine at the N-terminus and a free carboxylic acid at the C-terminus. Four of the fifteen are proline, three of them consecutive, and proline's ring restricts the conformations the backbone can adopt around it. The chain carries three acidic side chains, one glutamate and two aspartates, against a single lysine.

TB-500 is catalogued as a synthetic peptide corresponding to thymosin β4, a single chain of forty-three residues. The CAS number, formula (C212H350N56O78S) and molecular weight listed for it are those of that full-length chain, and at 4963.44 g/mol it is about three and a half times the mass of BPC-157. The listed formula contains a single sulfur atom.

The blends in this area are co-lyophilised: two or more peptides dried together into a single solid in one vial. A blend has no single molecular formula, CAS number or molecular weight. It is specified instead by naming its components, each with its own identifiers, and by the combined net content of the vial. Where a split between components is stated, it is a separate figure from that combined net content.

Identifiers at a glance

In the table, each single peptide carries a CAS number, a molecular formula, a molecular weight and a residue count, while a blend is listed by name and price per milligram, since a mixture of chains has no single formula or CAS number. BPC-157, at 1419.53 g/mol for fifteen residues, and TB-500, at 4963.44 g/mol for forty-three, show the spread across the single peptides. The price column divides each vial's price by its stated content in milligrams; for a blend, that is the combined content of all its components.

CompoundCAS numberMolecular formulaMolecular weightResiduesFrom, per mg
BPC-157137525-51-0C62H98N16O221419.53 g/mol15£3.00
TB-50077591-33-4C212H350N56O78S4963.44 g/mol43£7.50
BPC-157 / TB-500 Mix£3.00
KLOW£1.38

How this research area is defined

This research area is defined by what its single peptides leave out. A compound belongs here when it is a linear chain without cyclisation, lipidation or a metal centre, or when it is a co-lyophilised blend of such chains. Chain length is not part of the definition: the area runs from the fifteen residues of BPC-157 to the forty-three of TB-500, and both sit in the same class because the sequence itself carries the identity, with no ring, conjugate or bound ion to confirm alongside it.

Blends sit in the same area because each of their components does. A vial that combines BPC-157 and TB-500 holds two defined chains dried together, and each keeps its own CAS number, formula and expected mass. For a researcher choosing within the area, the practical distinction is between a single defined sequence, with one set of identifiers and one main chromatographic peak, and a blend, in which each component is resolved and confirmed against its own expected mass.

The single peptides here are also the simplest sequences in the catalogue to write out. BPC-157 is given in full three-letter notation on its product page, with a free amine and a free acid at its two ends, and the same notation is used for every linear chain in the store. That makes this area a practical starting point for reading peptide sequence notation.

Analytical considerations

Short, unmodified linear peptides are well suited to reversed-phase HPLC with ultraviolet detection at around 214 to 220 nm, where the peptide bond absorbs. BPC-157 has no tryptophan, tyrosine or phenylalanine, so it has almost no absorbance at 280 nm and detection relies on the peptide-bond region. Its acidic character makes retention sensitive to mobile-phase pH and to the ion-pairing agent, and proline-rich sequences can show broadened or split peaks where cis and trans forms of the prolyl bonds interconvert slowly on the timescale of the separation.

Mass spectrometry confirms identity against the expected mass: 1419.53 g/mol for BPC-157, while a chain the length of TB-500 appears as a series of multiply charged ions that are deconvoluted to a neutral mass. For a blend, one chromatogram shows a peak for each component, so the method has to resolve the components from one another and from each component's own related substances, and figures are reported per component rather than for the vial as a whole. Each component's identity is confirmed separately by its mass, because retention time alone cannot show which peak is which. Typical related substances across the area are deletion sequences, in which one residue is missing, and truncated chains from incomplete coupling during synthesis.

Further reading