Editing Entner–Doudoroff pathway (section)

=== Conversion of glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate ===
The G3P is converted to 1,3-bisphosphoglycerate in the presence of enzyme glyceraldehyde-3-phosphate dehydrogenase (an oxido-reductase).

The aldehyde groups of the triose sugars are [[oxidised]], and [[inorganic phosphate]] is added to them, forming [[1,3-bisphosphoglycerate]].

The hydrogen is used to reduce two molecules of [[NAD+|NAD<sup>+</sup>]], a hydrogen carrier, to give NADH '''+''' H<sup>+</sup> for each triose.

Hydrogen atom balance and charge balance are both maintained because the phosphate (P<sub>i</sub>) group actually exists in the form of a [[Phosphoric acid#Orthophosphoric acid chemistry|hydrogen phosphate]] anion (HPO<sub>4</sub><sup>2−</sup>), which dissociates to contribute the extra H<sup>+</sup> ion and gives a net charge of -3 on both sides.