L-ribulose-5-phosphate 4-epimerase

In enzymology, a L-ribulose-5-phosphate 4-epimerase is an enzyme that catalyzes the chemical reaction


 * L-ribulose 5-phosphate $$\rightleftharpoons$$ D-xylulose 5-phosphate

Hence, this enzyme has one substrate, L-ribulose 5-phosphate, and one product, D-xylulose 5-phosphate.

This enzyme belongs to the family of isomerases, specifically those racemases and epimerases acting on carbohydrates and derivatives. The systematic name of this enzyme class is L-ribulose-5-phosphate 4-epimerase. Other names in common use include phosphoribulose isomerase, ribulose phosphate 4-epimerase, L-ribulose-phosphate 4-epimerase, L-ribulose 5-phosphate 4-epimerase, AraD, and L-Ru5P. This enzyme participates in pentose and glucuronate interconversions and ascorbate and aldarate metabolism.

Structural studies
As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes and.