NADPH-dependent thioredoxin-disulfide reductase that reduces thioredoxins O1, O2 and F3. [thioredoxin]-dithiol + NADP(+) = [thioredoxin]-disulfide + H(+) + NADPH Binds 1 FAD per subunit. Homodimer. Ubiquitous. The active site is a redox-active disulfide bond. Belongs to the class-II pyridine nucleotide-disulfide oxidoreductase family. Truncated N-terminus. Sequencing errors. Truncated N-terminus. Truncated N-terminus.