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Suicide inactivation of catechol 2,3-dioxygenase from Pseudomonas putida mt-2 by 3-halocatechols.

Appl. Environ. Microbiol. 47, 500-505 (1984)
DOI PMC
Open Access Green as soon as Postprint is submitted to ZB.
The inactivation of catechol 2,3-dioxygenase from Pseudomonas putida mt-2 by 3-chloro and 3-fluorocatechol and iron-chelating agent Tiron (catechol-3,5-disulfonate) was studied. Whereas inactivation by Tiron is an oxygen-independent and mostly reversible process, inactivation by the 3-halocatechols was only observed in the presence of oxygen and was largely irreversible. The rate constants for inactivation (K2) were 1.62 x 10-3 sec-1 for 3-chlorocatechol and 2.38 x 10-3 sec-1 for 3-fluorocatechol. The inhibitor constants (K(i)) were 23 μM for 3-chlorocatechol and 17 μM for 3-fluorocatechol. The kinetic data for 3-fluorocatechol could only be obtained in the presence of 2-mercaptoethanol. Besides inactivated enzyme, some 2-hydroxyhexa-2,4-diendioic acid was formed from 3-chlorocatechol suggesting 5-chloroformyl-2-hydroxypenta-2,4-dienoic acid as the actual suicide product of meta-cleavage. A side product of 3-fluorocatechol cleavage is a yellow compound with the spectral characteristics of a 2-hydroxy-6-oxohexa-2,4-dienoic acid indicating 1,6-cleavage. Rates of inactivation by 3-fluorocatechol were reduced in the presence of superoxide dismutase, catalase, formate, and mannitol, which implies that superoxide anion, hydrogen peroxide, and hydroxyl radical exhibit additional inactivation.
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Publication type Article: Journal article
Document type Scientific Article
Corresponding Author
ISSN (print) / ISBN 0099-2240
e-ISSN 1098-5336
Quellenangaben Volume: 47, Issue: 3, Pages: 500-505 Article Number: , Supplement: ,
Publisher American Society for Microbiology (ASM)
Non-patent literature Publications
Reviewing status Peer reviewed
Institute(s) Abteilung Biophysikalische Strahlenforschung