Fructose-bisphosphate aldolase class I. Fructose-1,6-bisphosphate aldolase is an enzyme of the glycolytic and gluconeogenic pathways found in vertebrates, plants, and bacteria. The enzyme catalyzes the cleavage of fructose 1,6-bisphosphate to glyceraldehyde 3-phosphate and dihydroxyacetone phosphate (DHAP). Mutations in the aldolase genes in humans cause hemolytic anemia and hereditary fructose intolerance. The enzyme is a member of the class I aldolase family, which utilizes covalent catalysis through a Schiff base formed between a lysine residue of the enzyme and ketose substrates. Although structurally similar, the class II aldolases use a different mechanism and are believed to have an independent evolutionary origin.