Rabbit Anti-Human TXNRD2 polyclonal antibody for IHC-P. The reduced form of thioredoxin serves as a hydrogen donor, contributes to the up-regulation of various transcription factors and binds to and inhibits MAPKKK activity. Oxidized thioredoxin is converted back to the reduced form by Thioredoxin Reductase (TrxR2) , a redox active enzyme. There are two distinct isoforms in mammalian cells, TrxR1, a cytosolic protein and TrxR2, almost exclusively a mitochondrial protein. TrxR expression is induced in several tumors.