Amidated

Amidated is an adjective used in chemistry and biochemistry to describe a molecule that contains an amide group or has undergone amidation. In organic synthesis, amidation is the formation of an amide bond between a carboxyl group and an amine, typically via condensation with loss of water or by using coupling reagents.

In practice, lab-based amidation often relies on activated carboxyl derivatives or coupling reagents, such as DCC, EDC, HATU, or PyBOP, in the presence of a base. Direct dehydration methods exist but can be less efficient due to reversibility and side reactions. Enzymatic amidation also occurs in nature, notably through peptidylglycine alpha-amidating monooxygenase, which converts C-terminal glycine-extended peptides to C-terminal amides. In peptide synthesis, protective-group strategies are frequently employed to enable selective formation of the desired amide bond.

Biologically, many peptides are amidated at their C-terminus. C-terminal amidation can increase proteolytic stability and influence receptor binding and activity, making it a common post-translational modification in neuropeptides and peptide hormones.

Beyond biology, amidated describes materials containing amide linkages, such as polyamides (nylons) and various amide-containing lipids or surfactants. The term also applies to any molecule bearing a characteristic amide functional group.

Analytical considerations for amidated compounds include infrared spectroscopy, with amide I and II bands around 1650 cm-1 and 1540 cm-1, respectively, as well as NMR and mass spectrometry to confirm the presence and position of the amide bond.