IUBMB Enzyme Nomenclature


Accepted name: L-rhamnose isomerase

Reaction: L-rhamnose = L-rhamnulose

For diagram of reaction click here.

Other name(s): rhamnose isomerase; L-rhamnose ketol-isomerase

Systematic name: L-rhamnose aldose-ketose-isomerase

Comments: Contains two divalent metal ions located at different metal-binding sites within the active site. The enzyme binds the closed ring form of the substrate 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. While the enzyme from the bacterium Escherichia coli is specific for L-rhamnose, the enzyme from the bacterium Pseudomonas stutzeri has broad substrate specificity and catalyses the interconversion of L-mannose and L-fructose, L-lyxose and L-xylulose, D-ribose and D-ribulose, and D-allose and D-psicose [2].

Links to other databases: BRENDA, EXPASY, GTD, KEGG, Metacyc, PDB, CAS registry number: 9023-84-1


1. Domagk, G.F. and Zech, R. Über den Abbau der Desoxyzucker durch Bakterienenzyme. I. L-Rhamnose-Isomerase aus Lactobacillus plantarum. Biochem. Z. 339 (1963) 145-153.

2. Leang, K., Takada, G., Ishimura, A., Okita, M. and Izumori, K. Cloning, nucleotide sequence, and overexpression of the L-rhamnose isomerase gene from Pseudomonas stutzeri in Escherichia coli. Appl. Environ. Microbiol. 70 (2004) 3298-3304. [PMID: 15184124]

3. Korndorfer, I.P., Fessner, W.D. and Matthews, B.W. The structure of rhamnose isomerase from Escherichia coli and its relation with xylose isomerase illustrates a change between inter and intra-subunit complementation during evolution. J. Mol. Biol. 300 (2000) 917-933. [PMID: 10891278]

4. Yoshida, H., Yamada, M., Ohyama, Y., Takada, G., Izumori, K. and Kamitori, S. The structures of L-rhamnose isomerase from Pseudomonas stutzeri in complexes with L-rhamnose and D-allose provide insights into broad substrate specificity. J. Mol. Biol. 365 (2007) 1505-1516. [PMID: 17141803]

[EC created 1965]

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