peptide

Organic compound composed of a series of amino acids linked by peptide bonds (see covalent bond) between a carbon atom of one and a nitrogen atom of the next. Peptide chains longer than a few dozen amino acids are called proteins. Biosynthesis of peptides from a succession of amino acids carried by transfer RNA molecules takes place on ribosomes and is catalyzed and controlled by enzymes. Many hormones, antibiotics, and other compounds that participate in life processes are peptides.