Human mitochondrial thioredoxin reductase. cDNA cloning, expression and genomic organization

Antonio Miranda-Vizuete, Anastasios E. Damdimopoulos, José Rafael Pedrajas, Jan Åke Gustafsson, Giannis Spyrou

Research output: Contribution to journalArticlepeer-review

150 Scopus citations


We have isolated a 1918-bp cDNA from a human adrenal cDNA library which encodes a novel thioredoxin reductase (TrxR2) of 521 amino acid residues with a calculated molecular mass of 56.2 kDa. It is highly homologous to the previously described cytosolic enzyme (TrxR1), including the conserved active site CVNVGC and the FAD-binding and NADPH-binding domains. However, human TrxR2 differs from human TrxR1 by the presence of a 33-amino acid extension at the N-terminus which hits properties characteristic of a mitochondrial translocation signal. Northern-blot analysis identified one mRNA species of 2.2 kb with highest expression in prostate, testis and liver. We expressed human TrxR2 as a fusion protein with green fluorescent protein and showed that in vivo it is localized in mitochondria. Removal of the mitochondrial targeting sequence abolishes the mitochondrial translocation. Finally, we determined the genomic organization of the human TrxR2 gene, which consists of 18 exons spanning about 67 kb, and its chromosomal localization at position 22q11.2.

Original languageEnglish (US)
Pages (from-to)405-412
Number of pages8
JournalEuropean Journal of Biochemistry
Issue number2
StatePublished - Apr 15 1999


  • CDNA cloning
  • Genomic organization
  • Mitochondria
  • Thioredoxin reductase

ASJC Scopus subject areas

  • Biochemistry


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