Question

34. Glutathione plays an important role in protecting cells from various types of damages caused by oxidative stress. Which is the most important cofactor in recycling (reduction) of glutathione by glutathione reductase from oxidized glutathione?

Select one:

a. NADH

b. FADH2

c. QH2

d. NADPH

e. FMN

Answer 1

d. NADPH acts as the most important cofactor in recycling of glutathione GSH from its oxidized form GSSG. Glutathione reductase enzyme plays an important role in the antioxidant activity of glutathione.

It is involved in the catalysis of the given reaction as follows:

References:

• Cheng HM, Fagerholm P, Chylack LT Jr. Response of the lens to oxidative-osmotic stress. Exp Eye Res. 1983;37(1):11-21. doi:10.1016/0014-4835(83)90145-8.
• Lee SM, Koh HJ, Park DC, Song BJ, Huh TL, Park JW. Cytosolic NADP(+)-dependent isocitrate dehydrogenase status modulates oxidative damage to cells. Free Radic Biol Med. 2002;32(11):1185-1196. doi:10.1016/s0891-5849(02)00815-8.
• Mezzetti A, Di Ilio C, Calafiore AM, et al. Glutathione peroxidase, glutathione reductase and glutathione transferase activities in the human artery, vein and heart. J Mol Cell Cardiol. 1990;22(9):935-938. doi:10.1016/0022-2828(90)91033-4.