The major source of NADPH for fatty acid synthesis

HEXOSE MONOPHOSPHATE (HMP) SHUNT An Alternate Pathway for Oxidation of Glucose Synonyms: Variously called as: Hexose monophosphate pathway or shunt Pentose phosphate pathway (PP-pathway) Pentose cycle Phosphogluconate pathway Warburg-Dickens-Lipman Pathway. Sources of NADPH Hexose monophosphate shunt or HMP pathway is the main source of NADPH. Oxaloacetate produced by citrate lyase in the cytoplasm can be reduced to malate by NADH + H+ and malate dehydrogenase. There is another cytoplasmic enzyme called malic enzyme (NADP-malate dehydrogenase). Malate is oxidatively decarboxylated to pyruvate and NADPH is produced. An enzyme called isocitrate dehydrogenase is present in the cytoplasm. It generates NADPH mainly in ruminants. It uses NADP as the coenzyme.Ref: Textbook of Medical Biochemistry, Eighth Edition, Dr (Brig) MN Chatterjea, page no: 354,418