Dimeric cytosolic transaldolase (TALDO1) catalyzes the reversible reaction of D-erythrose 4-phosphate and D-fructose 6-phosphate to form D-glyceraldehyde 3-phosphate and sedoheptulose 7-phosphate. Protein expressed from the cloned gene has been characterized biochemically and crystallographically (Banki et al. 1994; Thorell et al. 2000) and transaldolase deficiency in a patient has been correlated with a mutation in the TALDO1 gene (Verhoeven et al. 2001).