Cytosolic thioredoxin reductase (TR) is an FAD-containing homodimeric selenoenzyme which, together with thioredoxin (Trx) and NADPH, forms a powerful oxidoreductase system. Cytoplasmic glutathione peroxidase (GPX-1) is a selenoprotein with antioxidant activity. The TR/Trx system has been associated with cellular processes including regulation of cell growth, and modification of activity of transcription factors. TR may also act as an antioxidant. We have measured TR activity, TR concentration, and GPX-1 activity in human hepatic cytosols from foetuses and neonates. The concentration of TR was significantly greater (P < 0.05) in foetal (43.6, 37.9-50.8 mug/g protein, median, interquartile range) than in neonatal liver (11.6, 8.70-15.0 mug/g). This was also true of TR activity which was 2.1, 1.8-2.5 U/g protein in foetal, and 0.65, 0.44-0.74 U/g protein in neonatal liver (P < 0.0005). Similarly, GPX-1 activity was significantly higher (P < 0.005) in the foetal (199.7, 144.0-227.9 U/g protein) than in neonatal(77.0, 58.4-110.3 U/g protein) hepatic cytosol. Overall, foetal liver expressed approx. 3-fold higher activities of TR and GPX-1 than neonatal liver. (C) 2001 Elsevier Science B.V. All rights reserved.
|Number of pages||5|
|Journal||Biochimica et Biophysica Acta (BBA) - General Subjects|
|Publication status||Published - 15 Jun 2001|
- thioredoxin reductase
- fetal neonatal