Isomaltulose synthase

In enzymology, an isomaltulose synthase (EC 5.4.99.11) is an enzyme that catalyzes the chemical reaction

sucrose ${\displaystyle \rightleftharpoons }$ 6-O-Alpha-D-Glucopyranosyl-D-Fructofuranose

Hence, this enzyme has one substrate, sucrose (table sugar), and one product, 6-O-Alpha-D-Glucopyranosyl-D-Fructofuranose (also known as isomaltulose or Palatinose). It converts the α-1,2 glycosidic linkage between glucose and fructose in sucrose into the α-1,6 glycosidic linkage between glucose and fructose in isomaltulose.

This enzyme belongs to the family of isomerases. The systematic name of this enzyme class is sucrose glucosylmutase. Other names in common use include sucrose isomerase, sucrose alpha-glucosyltransferase, and trehalulose synthase.

The isomaltulose synthase of the bacterium Protaminobacter rubrum is commonly used in the industrial production of isomaltulose.^[1]

Structural studies

As of late 2007, 7 structures have been solved for this class of enzymes, with PDB accession codes 1M53, 1ZJA, 1ZJB, 2PWD, 2PWE, 2PWF, and 2PWG.

References

• Cheetham PS (1984). "The extraction and mechanism of a novel isomaltulose-synthesizing enzyme from Erwinia rhapontici". Biochem. J. 220 (1): 213–20. doi:10.1042/bj2200213. PMC 1153612. PMID 6743261.
• Cheetham PS, Imber CE, Isherwood J (1982). "The formation of isomaltulose by immobilized Erwinia rhapontici". Nature. 299 (5884): 628–631. Bibcode:1982Natur.299..628C. doi:10.1038/299628a0. S2CID 4355243.