10.41 Riboflavin Functions Nutrition Structure and mechanism of mammalian thioredoxin reductase: The active site is a redox active selenolthiol selenenylsulfide formed from the conserved cysteine selenocysteine sequence PNAS Question: Riboflavin nutritional status is assessed by measurement of which of the following enzymes after addition of FAD in vitro? (A): Transketolase (B): Glutathione reductase (C): Transaminase (D): Transaldolase Let us know Item Scheme showing the enzymatic reactions that catalyze the pyruvate dehydrogenase complex, including pyruvate dehydrogenase activity and diaphorase activity of DLD (A) as well as the glutathione reductase peroxidase activity (B).