cd00429

Ribulose-5-phosphate 3-epimerase (RPE). This enzyme catalyses the interconversion of D-ribulose 5-phosphate (Ru5P) into D-xylulose 5-phosphate, as part of the Calvin cycle (reductive pentose phosphate pathway) in chloroplasts and in the oxidative pentose phosphate pathway. In the Calvin cycle Ru5P is phosphorylated by phosphoribulose kinase to ribulose-1,5-bisphosphate, which in turn is used by RubisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase) to incorporate CO2 as the central step in carbohydrate synthesis.