Ribulose-5-phosphate 3-epimerase (RPE)

Ribulose-5-phosphate 3-epimerase (RPE) is an enzyme that catalyzes the reversible interconversion of D-ribulose 5-phosphate and D-xylulose 5-phosphate, a key reaction in both the Calvin cycle (carbon fixation in plants) and the non-oxidative phase of the pentose phosphate pathway in all domains of life[1][3][4][5]. It is a metalloenzyme with a (β/α)₈ TIM barrel fold, typically utilizing Fe²⁺, Zn²⁺, or Mn²⁺ as a cofactor, depending on the species[3][6]. In plants, RPE is a chloroplast-localized enzyme required for efficient CO₂ fixation and photosynthetic capacity[5]. In pathogens like Plasmodium falciparum, RPE activity is essential for the shikimate pathway—making it a potential antimalarial drug target[3]. Inhibition or deficiency of RPE reduces metabolic flux through its associated pathways, impacting biosynthetic and antioxidative capacity in cells. There are no clinical inhibitors or biomarkers currently used in medicine, but the enzyme's essentiality in various pathways makes it a point of interest in both basic biology and drug discovery.

Other names

Ribulose-phosphate 3-epimeraseRibulose 5-phosphate 3-epimeraseRPE2-1Phosphopentose epimerasePhosphoribulose epimerasePhosphoketopentose 3-epimeraseXylulose phosphate 3-epimerasePhosphoketopentose epimeraseD-ribulose 5-phosphate epimeraseD-ribulose-phosphate-3-epimeraseD-ribulose-5-P 3-epimeraseD-xylulose-5-phosphate 3-epimerasePentose-5-phosphate 3-epimerase[3]

Inhibition of the enzyme would block interconversion between ribulose 5-phosphate and xylulose 5-phosphate, potentially disrupting the pentose phosphate pathway and related carbon metabolism in pathogens or plants[3]