Regioselective syntheses of trehalose-containing trisaccharides using various glycohydrolases.

Two methods were investigated for the enzymic preparation of trehalose-containing trisaccharides. In the first, a solution of saccharides is circulated through an immobilized-glycosidase column and an activated-carbon column connected in series. In the second, two enzymes having different substrate specificities are sequentially used for condensation and subsequent specific hydrolysis. Thus, 3-O-beta-D-, 4-O-beta-D-, and 6-O-beta-D-galactopyranosyl-alpha,alpha-trehalose; 4-O-alpha-D- and 6-O-alpha-D-glucopyranosyl-alpha,alpha-trehalose; and 4-O-beta-D- and 6-O-beta-D-glucopyranosyl-alpha,alpha-trehalose were synthesized stereo- and regio-selectively.