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A novel quinone: Quinone methide isomerase generates quinone methides in insect cuticle
Author(s) -
Saul Steven,
Sugumaran Manickam
Publication year - 1988
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(88)80191-1
Subject(s) - quinone methide , quinone , manduca sexta , chemistry , isomerase , arthropod cuticle , cuticle (hair) , enzyme , adduct , biochemistry , stereochemistry , biology , insect , organic chemistry , botany , genetics
Insoluble cuticle‐bound enzyme(s) of Manduca sexta pharate pupae, which is known to convert N ‐acetyldopamine to N ‐acetylnorepinephrine through the intermediate formation of quinone methide, also converted exogenously supplied N ‐acetyldopamine quinone to N ‐acetylnorepinephrine. The presence of a quinone trap such as N ‐acetylcysteine in the reaction mixture containing N ‐acetyldopamine and cuticle prevented the formation of N ‐acetylnorepinephrine but readily yielded N ‐acetylcysteine‐ N ‐acetyldopamine quinone adduct as a dead‐end product. These results indicate the oxidation of N ‐acetyldopamine to its quinone and its enzyme‐catalyzed isomerization to quinone methide before yielding N ‐acetyl‐norepinephrine as the stable product. The role of this newly discovered isomerase in sclerotization of insect cuticle is discussed.