What Is BPC-157? Sequence, Structure and Analysis

BPC-157 is a synthetic linear peptide of fifteen amino acid residues with the sequence Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val, or GEPPPGKPADDAGLV in one-letter code. Its molecular formula is C62H98N16O22, its average molecular weight is 1419.5 g/mol and its CAS registry number is 137525-51-0. In the laboratory its identity is confirmed by mass spectrometry and its purity is measured by reversed-phase HPLC.

This page covers BPC-157 as a chemical substance: the sequence residue by residue, where the formula and mass come from, the structural features that shape how the peptide behaves in analysis, and what a certificate of analysis for it should show.

The BPC-157 sequence, residue by residue

Peptide sequences are written from the N-terminus, the free amino group, to the C-terminus, the free carboxyl group. BPC-157 starts with glycine and ends with valine, and neither end is modified: there is no N-terminal acetyl group and no C-terminal amide. In the conventions of peptide sequence notation it is written H-Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val-OH, where H- and -OH mark the unmodified termini.

The PubChem record gives the S configuration at every stereocentre, which corresponds to L-amino acids throughout. Glycine, at positions 1, 6 and 13, has no stereocentre.

Composition at a glance

Counting residues gives four prolines, three glycines, two alanines and two aspartic acids, plus one each of glutamic acid, lysine, leucine and valine. Two features stand out. Proline makes up more than a quarter of the chain, including a run of three at positions 3 to 5. And the peptide carries more acidic groups than basic ones: three side-chain carboxyls (Glu2, Asp10 and Asp11) and the C-terminal carboxyl, against one lysine side chain and the N-terminal amine. At neutral pH that balance gives a net charge of about −2, so BPC-157 behaves as an acidic peptide.

Where the formula and mass come from

Each of the fourteen peptide bonds forms with the loss of one molecule of water, so the molecular formula is the sum of the fifteen free amino acids minus 14 H2O. That arithmetic gives C62H98N16O22, the formula recorded for BPC-157 in PubChem (CID 9941957).

Two different masses describe the same formula, and they are used for different jobs:

Average molecular weights quoted for BPC-157 range from 1419.53 to 1419.56 g/mol. The spread is not a different molecule; it comes from rounding and from the atomic-weight table used. The older standard atomic weights (carbon 12.0107, hydrogen 1.00794, nitrogen 14.0067, oxygen 15.9994) give 1419.54 g/mol, while the current CIAAW abridged values (carbon 12.011, hydrogen 1.0080, nitrogen 14.007, oxygen 15.999) give 1419.56 g/mol. PubChem rounds to 1419.5. What matters on a certificate is that an observed mass is compared with the right kind of calculated mass, monoisotopic or average, and that the ion type is stated.

Structural features that matter in the lab

The sequence alone predicts several things about how BPC-157 behaves in analysis.

• No aromatic residues. BPC-157 contains no tryptophan, tyrosine or phenylalanine, so it absorbs almost no light at 280 nm. HPLC detection relies on the peptide bond, which absorbs strongly at around 210 to 220 nm.
• No cysteine or methionine. The formula contains no sulfur, so disulfide-linked dimers and methionine-sulfoxide variants, common impurity classes in other peptides, cannot form.
• No asparagine, no glutamine and no Asp-Gly pair. Deamidation needs an asparagine or glutamine side chain, and Asp-Gly is the sequence most prone to aspartimide formation, so neither route is expected to be a major source of related substances.
• A proline-rich chain. Peptide bonds that precede proline can adopt both cis and trans forms, so proline-rich peptides can show more than one set of signals in NMR spectra. Proline also leaves its mark in tandem mass spectra, as described below.
• Several ionisable groups. With four carboxyl groups and two amines, retention in reversed-phase HPLC depends on mobile-phase pH. Acidic modifiers such as trifluoroacetic acid keep the carboxyls protonated and give sharp, reproducible peaks.

How BPC-157 is analysed

Two complementary measurements establish that a batch is BPC-157 and how much of its peptide material is the target sequence. The methods are covered in depth in the guides to HPLC peptide purity and mass spectrometry for peptide identity.

Reversed-phase HPLC for purity

The sample is run on a C18 column with a water–acetonitrile gradient containing an acidic modifier, and the eluate is monitored by UV absorbance at 210 to 220 nm. Purity is reported as the area of the main peak expressed as a percentage of the total area of all integrated peaks in the chromatogram, at the stated detection wavelength. Synthesis by-products such as deletion sequences, which lack one residue, and truncated chains usually elute close to the main peak, and they are what the purity figure is designed to capture.

Mass spectrometry for identity

With electrospray ionisation, BPC-157 is expected to appear as the doubly protonated ion at m/z 710.36 alongside the singly protonated ion at m/z 1419.71, since its two basic sites, the N-terminal amine and the lysine side chain, limit how many protons it readily carries. MALDI usually gives the singly charged ion. An observed mass that agrees with the calculated value within the instrument's stated accuracy confirms the molecular formula.

Tandem mass spectrometry (MS/MS) goes further. The selected ion is broken along the backbone into b-series fragments, which keep the N-terminus, and y-series fragments, which keep the C-terminus, and the mass differences along each ladder spell out the sequence. Cleavage on the N-terminal side of proline is often favoured, so in a peptide with four prolines some fragments are expected to be much stronger than others, and an uneven ladder is not in itself a sign of a problem. Standard mass spectrometry cannot tell L-residues from D-residues, and it does not measure purity, which is why it is paired with HPLC.

Other measurements on a full certificate

Purity and net peptide content answer different questions: purity describes the composition of the peptide material, while net peptide content describes how much of the weighed powder is peptide at all.

Reading a BPC-157 certificate of analysis

A certificate is only as useful as the details it carries. For BPC-157, check four things:

1. Identity. The sequence should read GEPPPGKPADDAGLV, and the observed mass should match the calculated monoisotopic mass of 1418.70 Da or the average mass of 1419.5 Da, with the ion or calculation stated.
2. Purity. An HPLC figure with its method: column, gradient and detection wavelength, ideally with the chromatogram attached.
3. Batch and date. A batch or lot number and an analysis date that match the vial you hold.
4. Issuer and client. The laboratory that performed the analysis and the company the certificate was prepared for.

For our BPC-157, the purity specification is ≥99% (HPLC, supplier specification). Certificate status is shown on every product page, and certificates of analysis are published in the COA Library where available.

Storage of the sealed material

BPC-157 is supplied as a lyophilised solid in a sealed vial. Store the sealed vial at 2–8 °C for short-term storage, or at −20 °C and below for long-term storage, protect it from light and avoid repeated freeze-thaw cycles. Letting a cold vial reach room temperature before it is opened limits moisture pick-up by the solid.

BPC-157 belongs to the Peptide Fragments research area, alongside TB-500. Terms used on this page, from monoisotopic mass to net peptide content, are defined in the glossary.