The amitochondriate eukaryote Trichomonas vaginalis contains a divergent thioredoxin-linked peroxiredoxin antioxidant system.

Trichomonas is an amitochondriate parasitic protozoon specialized for an anaerobic lifestyle. Nevertheless, it is exposed to oxygen and is able to cope with the resultant oxidative stress. In the absence of glutathione, cysteine has been thought to be the major antioxidant.