N-beta-alanyldopamine: major role in insect cuticle tanning [Tobacco hornworm, Manduca sexta]

N-β-Alanyldopamine is the major tyrosine metabolite in the hemolymph and cuticle during pupal tanning in the tobacco hornworm, Manduca sexta L. Its concentration in hemolymph increases over 800-fold above larval levels by the start of tanning and decreases as the pupal cuticle darkens and hardens. It is a major catechol in species representing several insect orders and is the preferred substrate for pupal cuticular o-diphenol oxidase. In insects, N-β-alanyldopamine appears to be the main precursor for tanning chemicals at certain developmental stages.