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URN: urn:nbn:de:kobv:517-opus-16762
URL: http://opus.kobv.de/ubp/volltexte/2008/1676/


Andersen, Svend Olav ; Perter, Martin G. ; Roepstorff, Peter

Cuticle-catalyzed coupling between N-acetylhistidine and N-acetyldopamine

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Kurzfassung in Englisch

Several types of insect cuticle contain enzymes catalyzing the formation ofof adducts between N-acetyldopamine (NADA) and N-acetylhistidine (NAH). Two such adducts, NAH-NADA-I and NAH NADA-II, have been isolated and their structures determined.
In one of the adducts the link connecting the two residues occurs between the I-position (ß-position) in the NADA side chain and the 1-N atom (τ-N) in the imidazole ring of histidine. Diphenoloxidase activity alone is not sufficient for formation of this adduct, whereas extracts containing both diphenoloxidase and o-quinone-p-quinone methide isomerase activities catalyze the coupling reaction. The adduct consists of a mixture of two diastereomers and they are presumably formed by spontaneous reaction between enzymatically produced NADA-p-quinone methide and N-acetylhistidine.
The other adduct has been identified as a ring addition product of N-acetylhistidine and NADA. In contrast to the former adduct it can be formed by incubation of the two substrates with mushroom tyrosinase alone.
An adduct between N-acetylhistidine and the benzodioxan-type NADA-dimer is produced in vitro, when the N-acetylhistidine-NADA adduct is incubated with NADA and locust cuticle containing a 1,2-dehydro-NADA generating enzyme system.
Trimeric NADA-polymerization products of the substituted benzodioxan-type have been obtained from in vivo sclerotized locust cuticle, confirming the ability of cuticle to produce NADA-oligomers.
The results indicate that some insect cuticles contain enzymes promoting linkage of oxidized NADA to histidine residues. It is suggested that histidine residues in the cuticular proteins can serve as acceptors for oxidized NADA and that further addition of NADA-residues to the phenolic groups of bound NADA can occur, resulting in formation of protein-linked NADA-oligomers. The coupling reactions identified may be an important step in natural cuticular sclerotization.

Freie Schlagwörter (Englisch): sclerotization , quinone , quinone methide , o-quinone isomerase , Hyalophora cecropia , Locusta migratoria
Institut: Institut für Chemie
DDC-Sachgruppe: Chemie
Dokumentart: c Postprint
Schriftenreihe: Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe, ISSN 1866-8372
Bandnummer: paper 072
Quelle: Insect Biochemistry and Molecular Biology. - 22 (1992), 5, pp. 459 - 469. ISSN 0965-1748
Sprache: Englisch
Erstellungsjahr: 1992
Publikationsdatum: 29.08.2008
Bemerkung:
first published in:
Insect Biochemistry and Molecular Biology. - 22 (1992), 5, pp. 459 - 469
ISSN 0965-1748
DOI 10.1016/0965-1748(92)90142-2
Lizenz: Diese Nutzungsbedingung gilt nicht, wenn in den Metadaten eine modifizierende Lizenz genannt ist. Keine Nutzungslizenz vergeben - es gilt das deutsche Urheberrecht


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