ABSTRACT
The two major products of the pathway are nicotinamide adenine dinucleotide (reduced form; NADPH) and ribose 5-phosphate. Ribose 5-phosphate and its derivatives are components of important cellular molecules such as RNA, DNA, NAD+, flavine adenine dinucleotide (FAD), ATP and coenzyme A (CoA). Nicotinamide Adenine Dinucleotide Phosphate (NADPH) is required for many biosynthetic pathways and particularly for synthesis of fatty acids and steroids. The pathway has three stages: Stage 1 — Oxidative reactions that convert glucose 6-phosphate into ribulose 5-phosphate, generating two NADPH molecules. Stage 2 — Isomerization of ribulose 5-phosphate to ribose 5-phosphate and Stage 3 — Linkage of the pentose phosphate pathway to glycolysis via transketolase and transaldolase. The transketolase and transaldolase reactions are reversible, so the final products of the pentose phosphate pathway can change depending on the metabolic needs of the cell.
