Peptíðtengin

Peptíðtengin, also known as peptide bonds, are covalent chemical bonds that link amino acids together to form polypeptides and proteins. This bond is formed through a dehydration synthesis reaction, where the carboxyl group of one amino acid reacts with the amino group of another, releasing a molecule of water. The resulting linkage is an amide bond, but it is specifically referred to as a peptide bond in the context of amino acid chains.

Each peptide bond has a partial double bond character due to resonance, which restricts rotation around the bond and contributes to the planar structure of the peptide backbone. This rigidity plays a crucial role in determining the three-dimensional folding of proteins. The formation of a peptide bond is an energetically unfavorable process and requires cellular machinery, such as ribosomes, to facilitate it during protein synthesis. The sequence of amino acids linked by peptide bonds defines the primary structure of a protein. Cleavage of peptide bonds, which breaks down proteins into smaller peptides or individual amino acids, occurs through hydrolysis reactions, often catalyzed by enzymes called proteases.