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The main purpose of the pentose phosphate pathway is to regenerate NADPH from NADP+ through an oxidation/ reduction reaction. This reaction is coupled to the formation of ribose 5-phosphate from glucose 6-phosphate. NADPH is used for reductive reactions in anabolism, especially in fatty acid synthesis. In red blood cells, the major role of NADPH is to reduce the disulfide form of glutathione to the sulfhydryl form. The reduced glutathione is pertinent for maintaining the normal structure of red blood cells and for keeping hemoglobin in the ferrous state [Fe(II)]. The nonoxidative portion of the pathway creates carbon chain molecules ranging from 3 to 7 carbons. These compounds are intermediates in glycolysis and gluconeogenesis or other biosynthetic processes. The pentose phosphate pathway primarily produces NADPH, ribose 5-phosphate, fructose 6-phosphate, and glyceraldehyde 3-phosphate.