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The b-D-galactosidase from Bacillus circulans regioselectively galactosylates 1D-chiro-inositol and 1D-pinitol (1D-3-Omethyl-chiro-inositol) to give mono-and digalactosylated inositols in yields of up to 45%. The enzyme does not galactosylate 1L-chiroinositol or 1L-quebrachitol (1L-2-O-methyl-chiro-inositol). This is the first report of enzymatic glycosylation of chiro-inositol and its derivatives.Oligosaccharides containing inositol sugars such as 1D-chiro-inositol (DCI) (1) and 1D-pinitol (2) are the focus of current interest for their putative role as secondary messengers of insulin and their associated implications in the etiology of Type 2 diabetes. 1-5 Although the detailed structures of these secondary messengers remain elusive, they are believed to contain an amino sugar such as galactosamine linked to a phosphorylated inositol sugar such as 1, 2 or myo-inositol. 6 In addition, DCI and pinitol-based oligosaccharides have been isolated in high levels from the seeds of leguminous plants and are thought to provide protection for the organelles, enzymes, proteins etc. during dessiccation. 7,8 Glycoside hydrolases (glycosidases) are responsible for the cleavage of oligosaccharides into constituent monosaccharide units in vivo. In vitro, it is possible to drive the reaction in the reverse direction, i.e. to form interglycosidic linkages from monomeric sugar units. By employing glycosidases in this manner it is possible to circumvent classical organic synthesis methods and traditional labour-intensive extraction procedures in the production of oligosaccharides.The b-D-galactosidase from Bacillus circulans (EC 3.2.1.23) has been reported as being an excellent, high yielding catalyst for the formation of di-and trisaccharides with Galb1®4 linkages. 9-13 This enzyme catalyzes the transfer of Gal from p-nitrophenyl b-D-galactopyranoside (GalbOpNP) or lactose to Glc, GlcNAc, Gal and GalNAc, predominantly to the OH-4 position. 13Herein we describe the enzymatic synthesis and characterisation of the products from the enzyme catalyzed reactions of GalbOpNP with 1 and 2 employing the b-Dgalactosidase from B. circulans (Figures 1 and 2). 14 To our knowledge, this is the first report describing an enzymatic synthesis to prepare inositol containing oligosaccharides. β-Galactosidase from Bacillus circulans 5 OH OH HO OH OH OH OH HO HO OH OH

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