IUBMB Enzyme Nomenclature


Accepted name: ribulose-phosphate 3-epimerase

Reaction: D-ribulose 5-phosphate = D-xylulose 5-phosphate

For diagram of reaction click here, alternative click here.

Other name(s): phosphoribulose epimerase; erythrose-4-phosphate isomerase; phosphoketopentose 3-epimerase; xylulose phosphate 3-epimerase; phosphoketopentose epimerase; ribulose 5-phosphate 3-epimerase; D-ribulose phosphate-3-epimerase; D-ribulose 5-phosphate epimerase; D-ribulose-5-P 3-epimerase; D-xylulose-5-phosphate 3-epimerase; pentose-5-phosphate 3-epimerase

Systematic name: D-ribulose-5-phosphate 3-epimerase

Comments: The enzyme also converts D-erythrose 4-phosphate into D-erythrulose 4-phosphate and D-threose 4-phosphate.

Links to other databases: BRENDA, EXPASY, GTD, KEGG, Metacyc, PDB, CAS registry number: 9024-20-8


1. Ashwell, G. and Hickman, J. Enzymatic formation of xylulose 5-phosphate from ribose 5-phosphate in spleen. J. Biol. Chem. 226 (1957) 65-76.

2. Dickens, F. and Williamson, D.H. Pentose phosphate isomerase and epimerase from animal tissues. Biochem. J. 64 (1956) 567-578.

3. Hurwitz, J. and Horecker, B.L. The purification of phosphoketopentoepimerase from Lactobacillus pentosus and the preparation of xylulose 5-phosphate. J. Biol. Chem. 223 (1956) 993-1008.

4. Stumpf, P.K. and Horecker, B.L. The rôle of xylulose 5-phosphate in xylose metabolism of Lactobacillus pentosus. J. Biol. Chem. 218 (1956) 753-768.

5. Terada, H., Mukae, K., Hosomi, S., Mizoguchi, T. and Uehara, K. Characterization of an enzyme which catalyzes isomerization and epimerization of D-erythrose 4-phosphate. Eur. J. Biochem. 148 (1985) 345-351. [PMID: 3987693]

[EC created 1961, modified 1989]

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