Leishmania infantum: Provision of reducing equivalents to the mitochondrial tryparedoxin/tryparedoxin peroxidase system

• Type: Article in International Scientific Journal
• Date: 2008

Authors

castro, h (Author) Other; romao, s (Author) Other; gadelha, fr (Author) Other; tomas, am (Author) ICBAS

Journal

Title: Experimental Parasitology

Vol. 120

Pages: 421-423

ISSN: 0014-4894

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 9 Citations

Scopus - 10 Citations

Scientific classification

FOS: Medical and Health sciences > Health sciences

Other information

Authenticus ID: P-003-TF0

DOI: 10.1016/j.exppara.2008.09.002

Abstract (EN): Within the mitochondrion of Leishmania infantum, hydroperoxide metabolism relies on the activity of tryparedoxin-dependent peroxidases (TXNPxs). Tryparedoxins (TXNs) are thioredoxin-related oxidoreductases, which in vitro are reduced by the trypanothione reductase/trypanothione [TR/T(SH)(2)] redox couple. Still, there is no evidence that this actually occurs in the mitochondrion. This communication addresses the question of how the mitochondrial TXN/TXNPx system is reduced. First, using a digitonin fractionation assay, we show that TR activity is absent from the L. infantum mitochondrion. The possibility that this organelle possesses alternative electron sources for TXN/TXNPx is then investigated. Biochemical assays performed with purified recombinant enzymes, revealed that TR and T(SH)(2) can be replaced, albeit less efficiently, by the dihydrolipoamide dehydrogenase/lipoamide redox system as TXN/TXNPx electron donor. This result challenges the classical view that T(SH)(2) is the only reductant for TXNs and add new prospects regarding the involvement of 2-oxo acid dehydrogenase complexes in L. infantum mitochondrial hydroperoxide metabolism. (C) 2008 Elsevier Inc. All rights reserved,

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 3