Mutational Studies Confirm the Catalytic Triad in the Human Selenoenzyme Thioredoxin Reductase Predicted by Molecular Modeling

Three's company. Site-directed mutagenesis of Glu477 of the human thioredoxin reductase (see figure) to glutamine, alanine, or lysine led to a significant drop in enzymatic activity. This study reinforces previous theoretical calculations which suggested that a swapping catalytic triad exists in the active site of this enzyme.