Lesson 21 : Pentose Phosphate Pathway or HMP Shunt
Oxidative phase
In this phase, two molecules of NADP+ are reduced to NADPH, utilizing the energy from the conversion of glucose-6-phosphate into ribulose 5-phosphate
The entire set of reactions can be summarized as follows:
Reactants
Products
Enzyme
Description
Glucose6-phosphate + NADP+
? 6-phosphoglucono-?-lactone + NADPH
glucose 6-phosphate dehydrogenase
Dehydrogenation. The hemiacetal hydroxyl group located on carbon 1 of glucose 6-phosphate is converted into a carbonyl group, generating a lactone, and, in the process, NADPH is generated.
6-phosphoglucono-?-lactone + H2O
? 6-phosphogluconate + H+
6-phosphogluconolactonase
Hydrolysis
6-phosphogluconate + NADP+
? ribulose 5-phosphate + NADPH + CO2
6-phosphogluconate dehydrogenase
Oxidative decarboxylation. NADP+ is the electron acceptor, generating another molecule of NADPH, a CO2, and ribulose 5-phosphate.
Participants