Ribulose-phosphate 3-epimerase（RPE) is a member of the ribulose-phosphate 3-epimerase family. RPE is the enzyme which converts D-ribulose 5-phosphate into D-xylulose 5-phosphate in Calvin’s reductive pentose phosphate cycle. Therefore， the RPE enzyme has one substrate， D-ribulose 5-phosphate， and one product， D-xylulose 5-phosphate. RPE participates in three metabolic pathways: pentose phosphate pathway， pentose and glucuronate interconversions， and carbon fixation.
