TXN and cystic fibrosis: Increased potency versus native rhTRX was also observed for viscoelasticity normalization of CF airway mucus by ORP‐100 or ORP100S.[41] These results demonstrate that the persistence of the covalent ORP100S mixed‐disulfide greatly slows reversion of the target‐protein disulfide as compared to the transient reduction by native TRX, resulting in both greater potency and longer duration of activity.