English: Aldolase B catalytic cycle is represented. Each step is explained by an arrow-pushing mechanism. It's an intuitive summary of enzyme activity. In the first stage, the free enzyme attaches fructose 1,6-biphosphate through intermediate complex then Lys33 reacts with the FBP's carbonyl in order to form the imine. Since imines are very reactive molecules the cleavage becomes easier furthermore the participation of Asp229 lowers the activation energy so the C3-C4 bond breaks up and a molecule of glyceraldehyde 3-phosphate is released. The catalytic tautomerization yields dihydroxyacetone phosphate imine that is further hydrolyzed to dihydroxyacetone phosphate leaving the active center free.