Peptides

Part of speech: noun

Definitions

1. Short sequences composed of amino acids that serve as precursors for proteins
2. Molecules consisting of a few amino acids that are vital in biochemical activities and cellular functions
3. Compounds made up of a small number of amino acids linked together

Etymology: The surprising part is that "peptide" was named after digestion. The Ancient Greek "peptós" meant "cooked" or "digested," from "péptō," "to soften, ripen, or digest." In the 19th century, German chemists used "Pepton" for the products that result when proteins are broken down by digestive enzymes, and the name carried the idea of food that had already been digested. From that German word came "Peptid," a term for the smaller chains of amino acids that remain when proteins are broken down further. English took the chemical term as "peptide," and "peptone," the earlier name for partially broken-down protein, shares the same root. In English, "peptide" thus carries the trace of kitchen and digestive vocabulary, even though the modern meaning is strictly chemical.

Synonyms: amino acids, polypeptides