1,2-dehydro-N-beta-alanyldopamine as a new intermediate in insect cuticular sclerotization.

D Ricketts,M Sugumaran

doi:10.1016/s0021-9258(17)31779-9

D Ricketts, M Sugumaran

Open Access

https://doi.org/10.1016/s0021-9258(17)31779-9

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Abstract

Sclerotization of insect cuticle is an extremely important biochemical process for the successful survival of most insects. N-Acetyldopamine and N-beta-alanyldopamine are two widely used sclerotizing precursors. N-Acetyldopamine is converted by phenoloxidase, quinone isomerase, and quinone methide isomerase to generate the reactive intermediates quinone, quinone methide, and quinone methide imine amide for use in quinone tanning, quinone methide sclerotization, and alpha,beta-sclerotization, respectively. N-beta-Alanyldopamine has been claimed to be used only by phenoloxidase and quinone isomerase for quinone tanning and quinone methide sclerotization thereby attributing biochemical diversity to the coloration and strength of different cuticles. However, we demonstrate here that cuticular enzymes isolated from the larvae of Calliphora possess the capacity to generate 1,2-dehydro-N-beta-alanyldopamine from N-beta-alanyldopamine. Chemical synthesis of 1,2-dehydro-N-beta-alanyldopamine and its further oxidation are reported for the first time. Comparative biochemical studies confirm that both the sclerotizing precursors, N-acetyldopamine and N-beta-alanyldopamine, are used by all three different mechanisms of the unified theory of sclerotization.

Highlights

Isomerase, and quinone methide isomerase to generate 17) in recent years, led to the unification of the above three the reactive intermediates quinone, quinone methide, mechanisms (Fig. 1)
Ever, we demonstrate here that cuticular enzymes iso- phora larvae and report on its chemical and enzymatic oxidalated from the larvae ofCalliphora possess the capacity tion pathways
The deinvolved in the unified sclerotization, uiz. phenoloxidase, qui- composition of these quinonoid compoundswas accompanied by none isomerase, and quinone methide isomerase

Summary

Introduction

Isomerase, and quinone methide isomerase to generate 17) in recent years, led to the unification of the above three the reactive intermediates quinone, quinone methide, mechanisms (Fig. 1). Our studies confirm that both the universal to generate 1,2-dehydro-N-P-alanyldopaminferom N-P- sclerotizing precursors NADA(Fig1.

Results

Conclusion