TXN and cancer: This reduced motif can then reduce the substrates of thioredoxin reductase, including the active site disulfide between positions 32 and 35 of thioredoxin, glutaredoxin 2 (GRX2), PDI, thioredoxin-like-1, granulysin [19,20] and some small molecule substrates such as selenite [21], dehydroascorbate [22], lipoic acid [23], ubiquinone [24], cytochrome C [25] or the cancer drugs motexafin gadolinium [26] and alloxan [27].