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What Are Peptides? A Plain-Language Guide
Peptides are short chains of amino acids.
Amino acids are the building blocks of proteins. When a few of them are linked together by peptide bonds, the result is a peptide.
Peptides vs. proteins
There is no exact line between the two. By convention, chains of up to roughly 50 amino acids are called peptides, and longer chains are called proteins. Insulin, with 51 amino acids, sits right at the border and is described both ways.
Why the names look the way they do
Many peptide names are abbreviations or code names, and they tell you something about the compound:
- GHK-Cu is a tripeptide (three amino acids: glycine, histidine, lysine) bound to copper. "Cu" is the chemical symbol for copper.
- KPV is named after its three amino acids: lysine, proline and valine.
- BPC-157 is a synthetic peptide of 15 amino acids.
- MOTS-c is a 16-amino-acid peptide encoded in mitochondrial DNA. The name stands for "mitochondrial open reading frame of the 12S rRNA type-c."
- TB-500 is commonly described as a synthetic fragment of thymosin beta-4.
What is not a peptide
Not everything in a peptide catalog is a peptide. NAD+ is a coenzyme, a different kind of molecule that is made of two nucleotides, not amino acids.
Research compounds and medicines
Some peptides are approved medicines, and insulin is the best-known example. Many others are used only in laboratory research and are not approved for human use. Nerolta products are supplied for laboratory research use only.
How to read a catalog entry
Look for the compound name, the amount per vial in milligrams and the form it is supplied in. Our next article explains what the label and the lab report should show.