IUBMB Enzyme Nomenclature


Accepted name: xylose isomerase

Reaction: D-xylose = D-xylulose

Other name(s): D-xylose isomerase; D-xylose ketoisomerase; D-xylose ketol-isomerase

Systematic name: D-xylose aldose-ketose-isomerase

Comments: Contains two divalent metal ions, preferably magnesium, located at different metal-binding sites within the active site. The enzyme catalyses the interconversion of aldose and ketose sugars with broad substrate specificity. The enzyme binds the closed form of its sugar substrate (in the case of glucose, only the α anomer) and catalyses ring opening to generate a form of open-chain conformation that is coordinated to one of the metal sites. Isomerization proceeds via a hydride-shift mechanism.

Links to other databases: BRENDA, EXPASY, GTD, KEGG, Metacyc, PDB, CAS registry number: 9023-82-9


1. Hochster, R.M. and Watson, R.W. Enzymatic isomerization of D-xylose to D-xylulose. Arch. Biochem. Biophys. 48 (1954) 120-129.

2. Slein, M.W. Xylose isomerase from Pasteurella pestis, strain A-1122. J. Am. Chem. Soc. 77 (1955) 1663-1667.

3. Yamanaka, K. Purification, crystallization and properties of the D-xylose isomerase from Lactobacillus brevis. Biochim. Biophys. Acta 151 (1968) 670-680. [PMID: 5646045]

4. Carrell, H.L., Glusker, J.P., Burger, V., Manfre, F., Tritsch, D. and Biellmann, J.F. X-ray analysis of D-xylose isomerase at 1.9 Å: native enzyme in complex with substrate and with a mechanism-designed inactivator. Proc. Natl. Acad. Sci. USA 86 (1989) 4440-4444. [PMID: 2734296]

5. Collyer, C.A. and Blow, D.M. Observations of reaction intermediates and the mechanism of aldose-ketose interconversion by D-xylose isomerase. Proc. Natl. Acad. Sci. USA 87 (1990) 1362-1366. [PMID: 2304904]

6. Whitlow, M., Howard, A.J., Finzel, B.C., Poulos, T.L., Winborne, E. and Gilliland, G.L. A metal-mediated hydride shift mechanism for xylose isomerase based on the 1.6 Å Streptomyces rubiginosus structures with xylitol and D-xylose. Proteins 9 (1991) 153-173. [PMID: 2006134]

7. Allen, K.N., Lavie, A., Glasfeld, A., Tanada, T.N., Gerrity, D.P., Carlson, S.C., Farber, G.K., Petsko, G.A. and Ringe, D. Role of the divalent metal ion in sugar binding, ring opening, and isomerization by D-xylose isomerase: replacement of a catalytic metal by an amino acid. Biochemistry 33 (1994) 1488-1494. [PMID: 7906142]

[EC created 1961 (EC created 1972, part incorporated 1978)]

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