C. Leitner et al., Enzymatic redox isomerization of 1,6-disaccharides by pyranose oxidase andNADH-dependent aldose reductase, J MOL CAT B, 11(4-6), 2001, pp. 407-414
Pyranose 2-oxidase, a homotetrameric FAD-flavoprotein from the basidiomycet
e Trametes multicolor, catalyzes regioselectively the oxidation of the 1 --
> 6 disaccharides allolactose [beta -D-Gal p-(1 --> 6)-D-Glc], gentiobiose
[beta -D-Glc p-(1 --> 6)-D-Glc], melibiose [alpha -D-Gal p-(1 --> 6)-D-Glc]
, and isomaltose [alpha -D-Glc p-(1 --> 6)-D-Glc] at position C-2 of their
reducing moiety, The resulting glycosyl D-arabino-hexos-2-uloses can be red
uced specifically at C-l by NAD(P)H-dependent aldose reductase from the yea
st Candida tenuis. By this novel, two-step redox isomerization process the
four disaccharide substrates could be converted to the corresponding keto-d
isaccharides allolactulose [beta -D-Gal p-(1 --> 6)-D-Fru], gentiobiulose [
beta -D-Glc p-(1 --> 6)-D-Fru], melibiulose [alpha -D-Gal p-(1 --> 6)-D-Fru
], and isomaltulose (palatinose, [alpha -D-Glc p-(1 --> 6)-D-Fru]) in high
yields. These products could find application in food technology as alterna
tive sweeteners. (C) 2001 Elsevier Science B.V. All rights reserved.