Metabolic Reactions  in the HMP Pathway

The hexose monophosphate pathway is responsible for  the generation of a substantialfraction of the cytoplasmic NADPH required  for biosynthetic reactions, and for thegeneration  of  ribose-5-phosphate for nucleotide synthesis. Hence,  there are the  followingtwo phases of HMP pathway:

1)  In the oxidation pathway, glucose-6-phosphate is converted  to  ribulose-5-phosphateby dehydrogenation  and decarboxylation reactions.

2)  In the nonoxidative phase,  ribulose-5-phosphate is converted back to glucose-6-phosphate by a series of reactions involving transketolase and transaldolase.