BIOTECHNOLOGY LETTERS Volume 17 No.1 (January 1995) p.4548 Received 30th November EFFICIENT CHEMOSELECTIVE SYNTHESIS OF 3,4’- DIHYDROXYPROPIOPHENONE 3-O-P-D-GLUCOSIDE BY THERMOPHILIC P-GLYCOSIDASE FROM SULFOLOBUS SOLFATARICUS Antonio Trincone*, Edoardo Pagnotta Istituto per la Chimica di Molecole di Interesse Biologico CNR, Via Toiano, 6 80072 Arco Felice (Naples) Italy Summary. A comparison of different systems for the /3-glycosidase-atalyzed synthesis of 3,4’- dihydroxypropiophenone 3-0-/3-D-glucoside is reported including various enzymatic sources and d#erent reaction conditions. The best yield was obtained using thermophilic /3-glycosidase from Sulfolobus solfataricus. INTRODUCTION Glycosidases can catalyze a reverse hydrolytic reaction or a transglycosylation for the synthesis of glycosides (Toone et al. 1989; Wong and Whitesides, 1994); an increase in donor or acceptor concentration seems quite effective for increasing yield of products, side-product formation or enzyme inactivation are, however, usual problems in these reactions. Thermophilic p-glycosidase from Sulfolobus solfataricus has been used to catalyze the formation of glycosides of a variety of aglycones from simple alcohols to more complex molecules relating the regioselectivity of the reaction to the structure of the molecule to be functionalized (Trincone et al. 1994a). In particular in the successful synthesis and stereochemical determination of aleppotrioloside, a plant glucoside (Trincone et al. 1994b), excellent regioselectivity has been obtained towards a primary hydroxyl group while tertiary and secondary hydroxyl groups are present in the molecule. Moreover good yield and absolute chemoselectivity were achieved for the synthesis of 2-hydroxy and 3-hydroxy benzyl p-D- glucosides (Trincone et al. 1994a) indicating that in transglycosilation reactions it is possible to avoid (or reduce) a cumbersome use of protective groups. These results prompted us to apply thermophilic enzyme for the synthesis of a natural glucoside, 3,4’-dihydroxypropiophenone 3- O-P-D-glucoside, 2a, from Bet&a plafyphylla var. japonica possessing repellent and anti- feedant activity that deserves further biological studies (Mori et al. 1992). Chemical synthesis of 1 was performed as previously reported by Mori that describes also the use of a lactase from Kluyveromyces lactis for the synthesis of 2a in the presence of different co-solvents (Mori et al. 1992). In this paper we report the synthesis of 2a starting from 1 as acceptor, and using as donors glucose or phenyl-p-D-glucoside. Different mesophilic and thermophilic biocatalysts were used, two commercially available p-glucosidases from almond and from Caldocellum 45