Erythrose 4-phosphate is a phosphate of the simple sugar erythrose. It is an intermediate in the pentose phosphate pathway and the Calvin cycle. The enzyme transaldolase catalyzes the formation of erythrose 4-phosphate and fructose 6-phosphate from sedoheptulose 7-phosphate and glyceraldehyde 3-phosphate. This reaction is a part of the non-oxidative phase of the pentose phosphate pathway. In the Calvin cycle, the enzyme fructose-bisphosphate aldolase catalyzes the formation of sedoheptulose 1,7-bisphosphate from erythrose 4-phosphate and dihydroxyacetone phosphate. In addition, it serves as a precursor in the biosynthesis of the aromatic amino acids tyrosine, phenylalanine, and tryptophan. It is used in the first step of the shikimate pathway. At this stage, phosphoenolpyruvate and erythrose-4-phosphate react to form 3-deoxy-D-arabinoheptulosonate-7-phosphate (DAHP), in a reaction catalyzed by the enzyme DAHP synthase. It also used in 3-hydroxy-1-aminoacetone phosphate biosynthesis, which is a precursor of vitamin B6 in DXP-dependent pathway. Erythrose-4-phosphate dehydrogenase is used to produce erythronate-4-phosphate.