liu.seSearch for publications in DiVA
Change search
ReferencesLink to record
Permanent link

Direct link
The mammalian cytosolic selenoenzyme thioredoxin reductase reduces ubiquinone. A novel mechanism for defense against oxidative stress
Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden.
Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden.
Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden.
Karolinska Institutet, Huddinge, Sweden.
Show others and affiliations
2003 (English)In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 278, no 4, 2141-2146 p.Article in journal (Refereed) Published
Abstract [en]

The selenoprotein thioredoxin reductase (TrxR1) is an essential antioxidant enzyme known to reduce many compounds in addition to thioredoxin, its principle protein substrate. Here we found that TrxR1 reduced ubiquinone-10 and thereby regenerated the antioxidant ubiquinol-10 (Q10), which is important for protection against lipid and protein peroxidation. The reduction was time- and dose-dependent, with an apparent K(m) of 22 microm and a maximal rate of about 12 nmol of reduced Q10 per milligram of TrxR1 per minute. TrxR1 reduced ubiquinone maximally at a physiological pH of 7.5 at similar rates using either NADPH or NADH as cofactors. The reduction of Q10 by mammalian TrxR1 was selenium dependent as revealed by comparison with Escherichia coli TrxR or selenium-deprived mutant and truncated mammalian TrxR forms. In addition, the rate of reduction of ubiquinone was significantly higher in homogenates from human embryo kidney 293 cells stably overexpressing thioredoxin reductase and was induced along with increasing cytosolic TrxR activity after the addition of selenite to the culture medium. These data demonstrate that the selenoenzyme thioredoxin reductase is an important selenium-dependent ubiquinone reductase and can explain how selenium and ubiquinone, by a combined action, may protect the cell from oxidative damage.

Place, publisher, year, edition, pages
American Society for Biochemistry and Molecular Biology, 2003. Vol. 278, no 4, 2141-2146 p.
National Category
Medical and Health Sciences
URN: urn:nbn:se:liu:diva-98800DOI: 10.1074/jbc.M210456200PubMedID: 12435734OAI: diva2:655906
Available from: 2013-10-14 Created: 2013-10-14 Last updated: 2013-10-21Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Search in DiVA

By author/editor
Spyrou, Giannis
In the same journal
Journal of Biological Chemistry
Medical and Health Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 40 hits
ReferencesLink to record
Permanent link

Direct link