L-rhamnose isomerase (RhaA)

L-rhamnose isomerase (RhaA) Accepted Name L-rhamnose isomerase. Alternative Name(s) Rhamnose isomerase. Reaction catalysed L-rhamnopyranose  <=>  L-rhamnulose Cofactor(s) Divalent cation. Comment(s) The enzyme binds the closed ring form of the substrate and catalyzes 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 catalyzes the interconversion of L-mannose and L-fructose, L-lyxose and L-xylulose, D-ribose and D-ribulose, and D-allose and D-psicose.