Amino Acid
Amino acids are small molecules that link together in chains to build peptides and proteins. They are often called the building blocks of both.
Where the word comes from
The name records the two chemical groups every amino acid carries. “Amino” comes from “amine,” the family name early chemists gave nitrogen-containing compounds related to ammonia. “Acid” is from Latin acidus, “sour” — the taste that first defined acids. So an amino acid is literally a molecule with both an amine group and an acid group. The first amino acids were isolated and described in the early 1800s.
What it means here
Twenty standard amino acids appear in nature, and the order they are linked in — the sequence — is what defines a peptide. Change one amino acid and the result is a different molecule, with a different molecular weight and a different fit at its receptor. That is why lab-made analogs of natural peptides often differ from the original by only one or two amino acids. When a product page lists a sequence, it is listing that peptide’s amino acids in order.
Words you’ll see together
- sequence — the order of amino acids in a chain, listed on product pages
- residue — what papers call one amino acid once it is linked inside a chain
- N-terminal / C-terminal — the two ends of a chain, named for the chemical group each one exposes
- tripeptide — a chain of exactly three amino acids, a label used for the shortest peptides
Related terms
- Peptide — a short chain of amino acids; proteins are long chains
- Molecular weight — set by which amino acids the chain contains
- Receptor — the sequence shapes how a peptide fits its receptor
Where it appears in our catalog
- BPC-157 — sequence listed in the product’s technical details
- Semax — a short peptide whose sequence is based on a natural hormone fragment
- What research peptides are — the plain-language starting point
