Recycling of the High Valence States of Heme Proteins by Cysteine Residues of Thimet-Oligopeptidase

The peptidolytic enzyme THIMET-oligopeptidase (TOP) is able to act as a reducing agent in the peroxidase cycle of myoglobin (Mb) and horseradish peroxidase (HRP). The TOP-promoted recycling of the high valence states of the peroxidases to the respective resting form was accompanied by a significant...

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Detalles Bibliográficos
Autores principales: Ferreira, Juliana C., Icimoto, Marcelo Y., Marcondes, Marcelo F., Oliveira, Vitor, Nascimento, Otaciro R., Nantes, Iseli L.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2013
Materias:
Research Article
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3815109/
https://www.ncbi.nlm.nih.gov/pubmed/24223886
http://dx.doi.org/10.1371/journal.pone.0079102
Descripción
Sumario:The peptidolytic enzyme THIMET-oligopeptidase (TOP) is able to act as a reducing agent in the peroxidase cycle of myoglobin (Mb) and horseradish peroxidase (HRP). The TOP-promoted recycling of the high valence states of the peroxidases to the respective resting form was accompanied by a significant decrease in the thiol content of the peptidolytic enzyme. EPR (electron paramagnetic resonance) analysis using DBNBS spin trapping revealed that TOP also prevented the formation of tryptophanyl radical in Mb challenged by H(2)O(2). The oxidation of TOP thiol groups by peroxidases did not promote the inactivating oligomerization observed in the oxidation promoted by the enzyme aging. These findings are discussed towards a possible occurrence of these reactions in cells.

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