1. Draw fully deprotonated 2,3 diphosphoglycerate (DPG).
2. Convert glyceraldehyde to glyceraldehyde phosphate (GAP), also called glyceraldehyde-3-phosphate (G3P). Draw the fully protonated form.
3. Convert dihydroxyacetone to fully protonated dihydroxyacetone phosphate (DHAP).
4. In the enzyme catalyzed reaction that converts DHAP to GAP, there is an ene-diol intermediate bound to the enzyme. Convert DHAP to that intermediate. Draw the fully protonated form.