Cellular defense systems against reactive oxygen
species (ROS) include thioredoxin reductase (TrxR)
and glutathione reductase (GR). They generate
sulfhydryl-reducing systems which are coupled to
antioxidant enzymes, the thioredoxin and glutathione
peroxidases (TPx and GPx). The fruit fly Drosophila
lacks a functional GR, suggesting that the thioredoxin
system is the major source for recycling glutathione.
Whole genome in silico analysis identified
two non-selenium containing putative GPx genes. We
examined the biochemical characteristics of one of
these gene products and found that it lacks GPx activity
and functions as a TPx. Transgene-dependent
overexpression of the newly identified Glutathione
peroxidase homolog with thioredoxin peroxidase activity
(Gtpx-1) gene increases resistance to experimentally
induced oxidative stress, but does not compensate
for the loss of catalase, an enzyme which,
like GTPx-1, functions to eliminate hydrogen peroxide.
The results suggest that GTPx-1 is part of the
Drosophila Trx antioxidant defense system but acts in
a genetically distinct pathway or in a different cellular
compartment than catalase.
Biological Chemistry keeps you up-to-date with the latest advances in the molecular life sciences. The journal publishes Research Articles, Short Communications, Reviews and Minireviews. Areas include: general biochemistry/pathobiochemistry, structural biology, molecular and cellular biology, genetics and epigenetics, virology, molecular medicine, plant molecular biology/biochemistry and novel experimental methodologies.