Probable thiol-disulfide oxidoreductase involved in the redox regulation of enzymes of both reductive pentose phosphate pathway (Calvin-Benson cycle) and oxidative pentose phosphate pathway. Glutathionylation at Cys-136 decreases its ability to be reduced by ferredoxin-thioredoxin reductase and reduces its efficiency in activating target chloroplastic enzymes. Belongs to the thioredoxin family. Plant F-type subfamily.