Understand the source comparison
Pe-22-28 Quality Real vs Fake: Comparison
The table below compares authentic research-grade Pe-22-28 against common low-quality or counterfeit versions across synthesis, testing, and storage standards. Understanding these differences is critical. Visually identical powders can differ by orders of magn
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- The table below compares authentic research-grade Pe-22-28 against common low-quality or counterfeit versions across synthesis, testing, and storage standards. Understanding these differences is critical. Visually identical powders can differ by orders of magnitude in purity and biological activity.
- Synthesis Method
- Solid-phase peptide synthesis (SPPS) with pharmaceutical-grade Fmoc/Boc-protected amino acids; stepwise coupling verified after each cycle
- SPPS with technical-grade reagents; minimal or no cycle-by-cycle verification; higher deletion sequence rate
- Authentic synthesis uses reagent-grade amino acids and validates each coupling step. Fake batches skip validation, allowing sequence errors to propagate undetected
- Purity (HPLC)
- ≥98% purity; single dominant peak on chromatogram; raw HPLC data provided
- 85–92% purity (or undisclosed); multiple peaks indicating impurities; summary certificate only or digitally altered chromatograms
- HPLC purity ≥98% is non-negotiable for reproducible research. Anything below 95% introduces too much variability from truncated peptides and synthesis byproducts
- Amino Acid Sequencing
- Verified 28-residue sequence (Gly-Arg-Gln-Arg-His-Gly-Gln-Asn-Gly-Glu-Arg-Gly-Ala-Pro-Gly-Gly-Lys-Gly-Asp-Thr-His-Gly-Asn-Gln-Pro-Gly-Ala-Pro); mass spectrometry confirms ~2,611 Da
- Sequence not verified; mass spectrometry absent or shows incorrect molecular weight (±100–300 Da)
- A single amino acid substitution or deletion eliminates TREK-1 binding. Sequence verification via MS is the only proof the peptide is structurally correct
- Sterility & Endotoxin
- Sterile filtered (0.22 µm); LAL endotoxin testing <1 EU/mg; lyophilised in cleanroom environment
- No sterile filtration; endotoxin levels unknown or untested; lyophilised in non-sterile facility
- Endotoxin contamination confounds in vivo and cell culture studies even at low concentrations. Unsterile peptides are biologically unreliable regardless of chemical purity
- Lyophilisation Quality
- Controlled freeze-drying (24–48 hours); fine white powder; reconstitutes completely in <60 seconds
- Rapid or incomplete lyophilisation; clumpy or discoloured powder; slow or incomplete reconstitution with visible particulates
- Proper lyophilisation creates stable, moisture-free powder. Clumping or discolouration signals oxidation or moisture retention that accelerates degradation during storage
- Storage & Shipping
- Shipped with cold chain logistics (insulated packaging, gel ice packs); stored at −20°C before shipping
- Shipped at ambient temperature without insulation; storage conditions unknown or uncontrolled
- Temperature excursions during shipping denature peptides irreversibly. Cold chain logistics are mandatory, not optional, for maintaining peptide integrity