In enzymology, a L-rhamnose isomerase () is an enzyme that catalyzes the chemical reaction
Hence, this enzyme has one substrate, L-rhamnose, and one product, L-rhamnulose.
This enzyme belongs to the family of isomerases, specifically those intramolecular oxidoreductases interconverting aldoses and ketoses. The systematic name of this enzyme class is L-rhamnose aldose-ketose-isomerase. Other names in common use include rhamnose isomerase, and L-rhamnose ketol-isomerase. This enzyme participates in fructose and mannose metabolism.
As of late 2007, 6 structures have been solved for this class of enzymes, with PDB accession codes , , , , , and .