Nbetaalanyldopamine

N-beta-alanyldopamine, abbreviated NBAD, is an amide formed by the condensation of dopamine with beta-alanine. It is a catecholamine-derived molecule most prominently described in invertebrates, particularly insects, where it functions as a biochemical precursor rather than a classical neurotransmitter.

In insects, NBAD is produced by the enzyme NBAD synthetase, encoded by the ebony gene, from dopamine and beta-alanine. It serves as a key intermediate in the cuticle sclerotization (tanning) pathway. NBAD is oxidized to NBAD-quinone by phenoloxidase systems, and this reactive species crosslinks with cuticular proteins and chitin to harden and stabilize the exoskeleton. The NBAD pathway often operates in parallel with the dopamine–dopaquinone melanin pathway, influencing both pigmentation and mechanical properties of the cuticle. Shifts in NBAD levels can affect coloration and rigidity during development and molting.

NBAD has been a focus of biochemical and genetic studies on insect development and metabolism, illustrating how beta-alanyl conjugation diversifies catecholamine function in non-neural tissues. In contrast to insects, NBAD is not recognized as a major component of human physiology, and it is not used in medical practice. Overall, NBAD exemplifies how specialized metabolic routes in arthropods contribute to integumentary biology, including pigmentation and exoskeletal strength.