What does polypeptide mean?
A polypeptide is a chain of amino acid residues joined by peptide bonds. In living organisms, polypeptides are fundamental building blocks of proteins: chains of this kind can fold into precise three-dimensional shapes and perform structural, enzymatic, transport, or signaling functions. Insulin, for example, consists of two polypeptide chains linked by disulfide bonds. Scientists also make synthetic polypeptides for use as drugs, research tools, and biomaterials. The word is most appropriate when a relatively long amino-acid chain is meant. For shorter sequences, especially those involved in signaling, “peptide” is often more usual. Although “polypeptide” and “peptide” overlap in usage, there is no universally fixed minimum length that separates them. The term is consequently common in scientific literature and relatively uncommon in everyday speech.
nounA chain of amino acid residues joined by peptide bonds, especially one long enough to fold into a functional molecular structure. The term is used in biochemistry, molecular biology, medicine, and related fields for natural and synthetic chains of this kind.
- A chain of amino acid residues connected by peptide bonds, occurring naturally or produced synthetically and often functioning as part of a protein or signaling molecule.
"The hormone insulin is made of two polypeptide chains connected by disulfide bonds."
"The hormone insulin is made of two polypeptide chains connected by disulfide bonds."
"Researchers designed a synthetic polypeptide that binds to the target receptor."
The regular plural is polypeptides.
"Several short polypeptides act together to coordinate the cellular response."
Insulin’s two linked chains are polypeptides—molecular chains that help regulate the body’s use of sugar.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does polypeptide come from?
The word combines the prefix poly-, from Greek polus meaning “many,” with peptide, a scientific term derived from Greek peptikos, meaning “digestible” or “capable of being digested.” English borrowed peptide from French, and polypeptide was formed by adapting this established scientific element with the productive prefix poly-. The shared Greek root also appears in words such as peptic, peptone, and peptidase, all concerned with digestion or the breakdown of peptide bonds.
Related word forms
How polypeptide is actually used
This is a formal scientific term with essentially neutral connotation. It is especially common in biochemistry, molecular biology, medicine, and pharmacology.
Easily confused with polypeptide
A peptide may be a short amino-acid chain, whereas a polypeptide is generally understood as a longer chain, although there is no universally strict length dividing the two terms.