Reaction 5: Oxidation/Phosphate Ester Synthesis
This reaction is first an oxidation involving the coenzyme
NAD+. The aldehyde is oxidized to an acid as an intermediate
through the conversion of NAD+ to NADH + H+.
Then an inorganic phosphate is added in a phosphate esteer synthesis.
This and all remaining reactions occur twice for each glucose-6-phosphate
(six carbons), since there are now two molecules of 3-carbons
This reaction is catalyzed by glyceraldehyde-3-phosphate.