What are peptides?
A peptide is a short chain of amino acids joined by peptide bonds. How peptides differ from proteins, which peptides occur in nature, and which items in the catalog are not peptides.
Knowledge base
Background on working with research peptides: reading certificates of analysis, understanding purity, storing material, and the rules around Research Use Only.
Background and methods
What is a COA?
A certificate of analysis tells you what is in a batch and how it was measured. How to read one, and how to check that it belongs to your vial.
How to read a mass spectrum
A mass spectrum on a certificate of analysis shows m/z, not mass. On ionisation, charge states, monoisotopic and average mass, and peaks that do not belong to the peptide.
Why lyophilize?
Peptides are supplied as a freeze-dried powder because they break down quickly in solution. What happens during freeze-drying, and what it means for storage.
Storing peptides in the lab
Which chemical reactions make a peptide degrade, which amino acids are sensitive to them, and how to handle temperature, moisture, light and record keeping in the lab.
How to read a peptide sequence
A sequence is the order of the amino acids in a peptide. The abbreviations, the reading direction, and the symbols for modifications, explained.
How are peptides made? Synthesis and purification
From solution-phase chemistry to Merrifield's solid support, the Fmoc cycle, where impurities come from, purification by preparative HPLC, and what counterions do to the weight.
What does 99% purity mean?
A purity of 99% tells you about the composition of the peptide, not about the amount in the vial. What the number measures, and what it does not.
Peptide blends: reading the label and the COA
A blend is one vial holding two or more compounds in a fixed ratio. How the label states the amount, how such a mixture is measured, and what belongs on its certificate.
RUO explained: what is and is not allowed
Research Use Only is not a free pass. What the designation means, which limits come with it, and what a supplier and a laboratory need to do about it.
Bac water: why bacteriostatic?
Bacteriostatic water is sterile water with 0.9% benzyl alcohol. What the preservative does, how it differs from sterile water, and when it is not the right choice in the lab.
How to choose a reliable peptide supplier
Eight points for assessing a supplier of research peptides, from the certificate of analysis to the company details.
Compounds from A to Z
What is 5-Amino-1MQ?
5-Amino-1MQ is not a peptide but a small organic molecule studied as an inhibitor of the enzyme NNMT. Structure, salt form and counterion, the enzyme, the research and the status.
What is AOD-9604?
AOD-9604 is a synthetic peptide of sixteen amino acids modelled on the C-terminal end of human growth hormone. Structure, the 176-191 numbering, research and status.
What is BPC-157?
BPC-157 is a synthetic peptide of fifteen amino acids, described as a fragment of BPC, a substance from gastric juice. Its structure, origin, what the research describes, and its regulatory status.
What is cagrilintide?
Cagrilintide is a synthetic, long-acting analogue of the peptide hormone amylin, developed by Novo Nordisk and still investigational. Structure, publications, CagriSema and status.
What is CJC-1295? With and without DAC
Two related synthetic analogues of the first 29 amino acids of GHRH. The name CJC-1295 is used for both. What the difference is, and how to tell them apart.
What is epithalon (epitalon)?
Epithalon is a synthetic tetrapeptide with the sequence Ala-Glu-Asp-Gly, from the bioregulator research of the Khavinson group. Structure, origin and the state of the evidence.
What is GHK-Cu?
GHK is the tripeptide glycyl-histidyl-lysine; GHK-Cu is its complex with a copper(II) ion. Its structure, discovery in human plasma, the research, and its regulatory categories.
What is ipamorelin?
Ipamorelin is a synthetic five-residue peptide described as a selective agonist of the ghrelin receptor. Structure, its origin at Novo Nordisk, and its status.
What is KPV?
KPV is the tripeptide lysine-proline-valine, the last three amino acids of alpha-MSH. Structure, a pitfall when searching databases, the research and the status.
What is MOTS-c?
MOTS-c is a peptide of sixteen amino acids encoded not in the cell nucleus but in mitochondrial DNA. Structure, its discovery in 2015, and the state of the research.
What is NAD+?
NAD+ is not a peptide but a coenzyme found widely in nature. Its structure, the NAD+ and NADH pair, its role as an ADP-ribose donor and how to handle it in the lab.
What is oxytocin?
Oxytocin is a cyclic nonapeptide with a disulfide bridge between Cys1 and Cys6. Its structure, its history, its status as a medicine, and why research-grade oxytocin acetate is not that medicine.
What is retatrutide?
Retatrutide (LY3437943) is an investigational Eli Lilly peptide that acts on the GIP, GLP-1, and glucagon receptors. Its structure, publications, the TRIUMPH phase 3 program, and its status.
What is SS-31 (elamipretide)?
SS-31 is a synthetic tetrapeptide that binds cardiolipin, a lipid in the inner mitochondrial membrane. Structure, origin, and how the medicine differs from research material.
What is TB-500?
TB-500 is a trade name for a seven-amino-acid fragment of thymosin beta-4 with an acetyl group at the start. How it differs from the full protein, its structure, and its status.