D-xylose (D-glucose) isomerase and related enzymes in carbohydrate synthesis

Enzymatically catalysed isomerisation of free sugars is an important and ec onomically viable alternative to chemical means for achieving such transfor mations. The conversion Of D-glucose into D-fructose with D-xylose (D-gluco se) isomerase (EC 5.3.1.5) has become a large-scale industrial application producing more than ten million tons of fructose syrup annually. Due to the remarkable tolerance of this and related enzymes, for example, L-fucose is omerase (EC 5.3.1.3), for epimers, as well as chemically modified substrate analogues bearing nonnatural features, such as azido or fluoro substituent s, a large variety of interesting and novel synthetic applications has beco me feasible for these remarkably useful and easy-to-handle biocatalysts.