Purification and characterization of d-allulose 3-epimerase derived from Arthrobacter globiformis M30, a GRAS microorganism.

An enzyme that catalyzes C-3 epimerization between d-fructose and d-allulose was found in Arthrobacter globiformis strain M30. Arthrobacter species have long been used in the food industry and are well-known for their high degree of safety. The enzyme was purified by ion exchange and hydrophobic interaction chromatographies and characterized as a d-allulose 3-epimerase (d-AE).

Crystal structure of β-d,l-allose.

The title compound, C6H12O6, a C-3 position epimer of glucose, was crystallized from an equimolar mixture of d- and l-allose. It was confirmed that d-allose (l-allose) formed β-pyran-ose with a (4) C 1 ((1) C 4) conformation in the crystal. In the crystal, molecules are linked by O-H⋯O hydrogen bond, forming a three-dimensional framework.