The Journal of nutrition
-
The Journal of nutrition · May 2003
ReviewSelenoprotein metabolism and function: evidence for more than one function for selenoprotein P.
Biological functions of selenium are exerted by selenoproteins that contain selenocysteine in their primary structure. Selenocysteine is synthesized and inserted into proteins cotranslationally by a complex process. Families of selenoproteins include the glutathione peroxidases, the iodothyronine deiodinases and the thioredoxin reductases. ⋯ Brain tissue did not begin accumulating (75)Se until (75)Se-labeled selenoprotein P had begun appearing in the plasma after 30 min. These results suggest that tissues like liver can take up small-molecule forms of selenium whereas presence of the element in selenoprotein P facilitates uptake by tissues like brain. Thus, there is evidence for both antioxidant and selenium transport functions of selenoprotein P.
-
The Journal of nutrition · May 2003
Comparative StudyMethylenetetrahydrofolate reductase 677C-->T variant modulates folate status response to controlled folate intakes in young women.
A common genetic variant in the methylenetetrahydrofolate reductase (MTHFR) gene involving a cytosine to thymidine (C-->T) transition at nucleotide 677 is associated with reduced enzyme activity, altered folate status and potentially higher folate requirements. The objectives of this study were to investigate the effect of the MTHFR 677 T allele on folate status variables in Mexican women (n = 43; 18-45 y) and to assess the adequacy of the 1998 folate U. S. ⋯ Collectively, these data demonstrate that the MTHFR C-->T variant modulates folate status response to controlled folate intakes and support the adequacy of the 1998 folate U. S. RDA for all three MTHFR C677T genotypes.