Cytosolic ribulose-5-phosphate-3-epimerase (RPE), using Fe2+ as cofactor, catalyzes the reversible interconversion of D-ribulose 5-phosphate (RU5P) and D-xylulose 5-phosphate (XY5P) (Bose & Pilz 1985, Liang et al. 2011). The electrophoretic properties of RPE activity detected in extracts of mouse-human somatic cell hybrids suggest that the active form of the enzyme is a homodimer (Spencer & Hopkinson 1980). Ribulose-phosphate 3-epimerase-like protein 1 (RPEL1), based on sequence similarity, is suggested to function as RPE.
