noun, plural: peptide bonds
(1) The covalent bond joining amino acids, particularly at the carboxyl group of one amino acid to the amino group of the other amino acid, with the concomitant release of a molecule of water
(2) CO-NH amide bond
Peptide bond (-CO-NH-) is an amide type of covalent bond. It joins amino acids via the carboxyl group of one amino acid and the amino group of the other amino acid. When two amino acids join, a concomitant release of water molecule occurs – a type of dehydration synthesis reaction. Water is formed when, for instance, two amino acids are joining together, one loses a hydrogen and oxygen from the carboxyl group while the other loses a hydrogen from the amine group.
Series of amino acids joined together make up a peptide. A peptide is one of the major biomolecules. Peptides may be classified based on the number of their monomeric units. For instance, a dipeptide is a peptide made up of two amino acids. A tripeptide is a peptide consisting of three amino acids.
A peptide bond is sometimes referred to as eupeptide bond since it is the more predominant type. A eupeptide bond is a peptide bond characterized by forming a link between alpha-carbonyl group of one amino acid to the N-2 of the other amino acid. The other peptide bond is the isopeptide bond, i.e. a peptide bond formed between the carboxyl group and an amino group of joining amino acids at position other than the alpha.
Peptide bonds are degraded through the process of hydrolysis, i.e. the addition of water. In living systems, the process may take place by using enzymes.