TXNDC1 is a thioredoxin (TXN)-related protein with disulfide reductase activity. The deduced 280-amino acid protein has a predicted molecular mass of 31.8 kD and contains an N-terminal signal sequence, a TRX-like domain with an active site sequence CPAC, and a transmembrane domain.

Northern blot analysis detected a 2.5-kb transcript in all tissues examined, with highest expression in kidney, liver, placenta, and lung. Confocal microscopy of intact HEK293 cells expressing TXNDC1 and Western analysis of subcellular fractions localized TXNDC1 primarily in the microsomal fraction in an endoplasmic reticulum (ER)-like staining pattern characterized by a diffuse network-like labeling of the cytoplasm and nuclear rim.