EC - L-arabinose isomerase

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IntEnz Enzyme Nomenclature


Accepted name:
L-arabinose isomerase
Other name:
L-arabinose ketol-isomerase
Systematic name:
α-L-arabinose aldose-ketose-isomerase




Requires a divalent metal ion (the enzyme from the bacterium Escherichia coli prefers Mn2+) [2]. The enzyme binds β-L-arabinopyranose [4] and catalyses ring opening to generate a form of open-chain conformation that facilitates the isomerization reaction, which proceeds via an ene-diol mechanism [5]. The enzyme can also convert α-D-galactose to D-tagatose with lower efficiency [4].

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0008733
CAS Registry Number: 9023-80-7
UniProtKB/Swiss-Prot: (115) [show] [UniProt]


  1. Heath, E.C., Horecker, B.L., Smyrniotis, P.Z. and Takagi, Y.
    Pentose formation by Lactobacillus plantarum. II. L-Arabinose isomerase.
    J. Biol. Chem. 231 : 1031-1037 (1958). [PMID: 13539034]
  2. Patrick, J. W., Lee, N.
    Purification and properties of an L-arabinose isomerase from Escherichia coli.
    J. Biol. Chem. 243 : 4312-4318 (1968). [PMID: 4878429]
  3. Nakamatu, T. and Yamanaka, K.
    Crystallization and properties of L-arabinose isomerase from Lactobacillus gayonii.
    Biochim. Biophys. Acta 178 : 156-165 (1969). [PMID: 5773448]
  4. Cheetham, P.S.J. and Wootton, A.N
    Bioconversion of D-galactose into D-tagatose.
    Enzyme Microb. Technol. 15 : 105-108 (1993).
  5. Banerjee, S., Anderson, F., Farber, G. K.
    The evolution of sugar isomerases.
    Protein Eng. 8 : 1189-1195 (1995). [PMID: 8869631]
  6. Manjasetty, B. A., Chance, M. R.
    Crystal structure of Escherichia coli L-arabinose isomerase (ECAI), the putative target of biological tagatose production.
    J. Mol. Biol. 360 : 297-309 (2006). [PMID: 16756997]
  7. Schray, K. J., Rose, I. A.
    Anomeric specificity and mechanism of two pentose isomerases.
    Biochemistry 10 : 1058-1062 (1971). [PMID: 5550812]

[EC created 1961]