Reaction 4: Split Molecule in half
The six carbon fructose diphosphate is spit into two three-carbon
compounds, an aldehyde and a ketone.
The slit is made between the C-3 and C-4 of the fructose.
The ring also opens at the anomeric carbon. The product on the
right is the glyceraldehyde.
Technically this is called a reverse aldol condensation.
This reaction is catalyzed by aldolase.