Complex sentence: In living cells, glutathione disulfide is reduced into two molecules of glutathione with NADPH/H + (Niacin Analog) catalyzed by the enzyme glutathione reductase.
Split into simpler sentences: In living cells, glutathione disulfide is reduced into two molecules of glutathione with reducing equivalents from the coenzyme NADPH. This reaction is catalyzed by the enzyme glutathione reductase.