Quinone methide formation from 4‐alkylcatechols: a novel reaction catalyzed by cuticular polyphenol oxidase

  title={Quinone methide formation from 4‐alkylcatechols: a novel reaction catalyzed by cuticular polyphenol oxidase},
  author={Manickam Sugumaran and Herbert Lipke},
  journal={FEBS Letters},
Oxidation of 4‐alkylcatechols by cuticular polyphenol oxidase gives quinone methides as initial products as opposed to the conventional quinones. This new reaction accounts for several conflicting observations on the catecholamine chemistry in insect cuticle. 
Phenoloxidase catalyzed coupling of catechols. Identification of novel coupling products.
The two dominating products from 4-methylcatechol and the main product from N-acetyldopamine were purified and identified by means of plasma desorption and electron impact mass spectrometry and by 1H- and 13C-NMR spectroscopy, indicating oxidative coupling between two catechols.
Model studies for insect protein sclerotization: Oxidative loss of the side chain from 4-substituted catechols
Abstract The oxidation of several 4-substituted catechols in aqueous solution, pH7 in the presence of aniline results in the formation of 4,5-dianilino-1,2-benzoquinone 2 and the anil of 2 , ( 3 ).
Biphenyltetrols and Dibenzofuranones from Oxidative Coupling of Resorcinols with 4‐Alkylpyrocatechols: New Ciues to the Mechanism of Insect Cuticle Sclerotization
Oxidation of 4-alkylpyrocatechols 2 by means of an insect diphenoloxidase (laccase) or K3 [Fe(CN)6] yields, in the presence of resorcinols 1 (R2 H), complex mixtures of products from which
Biological and toxicological consequences of quinone methide formation.
The role of quinone methides in the synthesis of several complex plant and animal polymers, including lignin, cuticle and melanin, and the role of alkylphenols in these various processes is reviewed.
Chemical Reactivities of ortho-Quinones Produced in Living Organisms: Fate of Quinonoid Products Formed by Tyrosinase and Phenoloxidase Action on Phenols and Catechols
The reactivities of o-quinones thus generated are responsible for oxidative browning of plant products, sclerotization of insect cuticle, defense reaction in arthropods, tunichrome biochemistry in tunicates, production of mussel glue, and most importantly melanin biosynthesis in all organisms.
A novel quinone: Quinone methide isomerase generates quinone methides in insect cuticle
Results indicate the oxidation of N‐acetyldopamine to its quin one and its enzyme‐catalyzed isomerization to quinone methide before yielding N‐acetyl‐norepinephrine as the stable product.
On the mechanism of formation of N-acetyldopamine quinone methide in insect cuticle
L'analyse de ces mecanismes a ete realisee a l'aide de 3 systemes enzymatiques de la cuticule chez des insectes differents a partir de precurseur de la scleritisation tel la N-acetyldopamine (NADA).
Oxidation of 3,4-dihydroxybenzyl alcohol: a sclerotizing precursor for cockroach ootheca.
The oxidation of 3,4-dihydroxybenzyl alcohol, one of the sclerotizing precursors for the tanning of the ootheca of cockroach Periplaneta americana, is reported for the first time. Mushroom tyrosinase
Oxidation of N-β-alanyldopamine by insect cuticles and its role in cuticular sclerotization
Results indicate that NBAD is oxidized to o -quinone and quinone methide derivatives, and NADA can be desaturated to α , β -dehydro- N -acetyldopamine, a probable intermediate in β-sclerotization.
Oxidation of 4-alkylphenols and catechols by tyrosinase: ortho-substituents alter the mechanism of quinoid formation.
An improved understanding of substituent effects on tyrosinase-catalyzed oxidation of catechols and phenols is necessary for the development of strategies for therapeutic compounds that are selectively toxic toward melanoma.


Characterization of the sclerotization enzyme(s) in locust cuticle
The enzymatic activities in the intact cuticle have been characterized and compared and the possibility cannot be excluded that a single enzyme is responsible for all the observed reactions.
Phenolic compounds released by mild acid hydrolysis from sclerotized cuticle: purification, structure, and possible origin from cross-links
Sclerotized cuticles from locusts and from beetles were partially hydrolyzed by means of dilute acetic acid, and a number of low-molecular weight phenols was isolated from the hydrolysates. Their
Products of in vitro oxidation of N-acetyldopamine as possible components in the sclerotization of insect cuticle
Results suggest that oxidation products different from those formulated usually for the crosslinkages between protein amino groups and N-acetyldopaquinone are deposited in darkly brown coloured insect cuticles during sclerotization.
Crosslink precursors for the dipteran puparium.
  • M. Sugumaran, H. Lipke
  • Chemistry, Medicine
    Proceedings of the National Academy of Sciences of the United States of America
  • 1982
During sclerotization of puparial proteins, tyrosine, lysine, and histidine were converted to highly basic aromatic metabolites, consistent with a crosslinking mechanism favoring covalent bonding between protein chains.
Phenoloxidases in larval cuticle of the blowfly, Calliphora vicina
It is suggested that enzyme A is involved in wound healing, and that enzyme B plays a role in sclerotization of the puparium.
Characterization of a trypsin-solubilized phenoloxidase from locust cuticle
The enzyme will oxidize a number of both ortho- and para-diphenols, and in contrast to untreated locust cuticle it is more active in releasing tritium located on the aromatic ring of N-acetyldopamine than in releasingtritium from the aliphatic side-chain of the same compound.
A procedure for isolation and concentration of catechols by chromatography on dihydroxyboryl cellulose.
Abstract A simple and highly sensitive column chromatographic method based on specific chelation of o -dihydroxyphenols to dihydroxyboryl cellulose has been developed for quantitative isolation and
Suicide substrates: mechanism-based enzyme inactivators
Abstract This review article defines suicide substrates as a class of irreversible inactivators of specific target enzymes where the target enzyme participates in its own destruction by catalytic
Cuticular phenoloxidase from the silkworm, Bombyx mori: Properties, solubilization, and purification
Cuticle-bound phenoloxidase from pupae of the silkworm, Bombyx mori, has optimum pH at 5.5, and Km values of hydroquinone and l-dopa for the enzyme were found to be 2.44 × 10−4M and 1.33 ×10−2 M, respectively.