polypeptide
Meaning of polypeptide: A polypeptide is a chain of many amino acids joined together, the structural building block from which one or more folds into a functional protein.
Definition of polypeptide
A polypeptide is a chain formed by many amino acids, the small molecules that link together in a specific sequence to build proteins. Each amino acid in the chain is joined to the next by a bond called a peptide bond, and the particular sequence of amino acids determines the chain's eventual shape and function.
A polypeptide differs somewhat from a protein in strict usage, since a protein is often made up of one or more polypeptide chains that have folded into a specific three dimensional shape, sometimes combining with other chains or with non protein components to form the finished, functional molecule.
The sequence and folding of a polypeptide chain determine what role it plays in the body, whether as a structural component, an enzyme that carries out a chemical reaction, or a signaling molecule such as certain hormones, which are themselves polypeptides of a particular sequence and length.
Used in a sentence
The laboratory analysis identified a polypeptide sequence associated with the condition being studied.
Good to know
The terms polypeptide and protein are often used loosely as though interchangeable, though strictly a protein is the folded, functional molecule that one or more polypeptide chains can form.
Word origin
Where “polypeptide” comes from
Formed from Greek poly-, meaning many, and peptide, from peptein, meaning to digest.