A peptide is a biologically occurring chemical compound containing two or more amino acids connected to one another by peptide bonds.
A peptide bond is a covalent bond that is formed between two amino acids when a carboxyl group or C-terminus of one amino acid reacts with the amino group or N-terminus of another amino acid in a condensation reaction (a molecule of water is released during the reaction). The resulting bond is a CO-NH bond and forms a peptide, or amide molecule. Likewise, peptide bonds are amide bonds.(More information about peptide bonds.)
The word “peptide” itself comes from πέσσειν, the Greek word meaning “to digest.” Peptides are an essential part of nature and biochemistry, and thousands of peptides occur naturally in the human body and in animals. In addition, new peptides are being discovered and synthesized regularly in the laboratory as well. Indeed, this discovery and innovation in the study of peptides holds great promise for the future in the fields of health and pharmaceutical development.