Glutathione reductase physiological function

Halliwell, B., and C. H. Foyer Properties and physiological function of a glutathione reductase purified from spinach leaves by affinity chromatography. Planta 139, 9 (1978). 

Use of physiological functional indices in relation to riboflavin deficiency (analogous to dark adaptation for vitamin A clotting factors for vitamin K, etc.) has not proved possible, because the analogous riboflavin-sensitive physiological processes are insufficiently specific or easily measurable for use in population studies. Of the biochemical indices, urinary excretion and the flavin-dependent enzyme, erythrocyte glutathione reductase, are generally considered to be the front-runners in the race for acceptance in human studies. These have already been described in the previous section. 

---