Remote control of enzyme selectivity: the case of stevioside and steviolbioside

The remote control of lipase PS site- and regioselectivity by substrate modification has been observed in the acetylation of stevioside () and steviolbioside (): deglucosylation at position C-19 changed the acylation site of the sophorose moiety linked at C-13. In fact, while esterification of gave mainly the corresponding 6″-O-acetylated derivative, acylation of gave exclusively the 6′-O-monoester. A possible rationale has been suggested, based on the conformational behavior of the substrates in different simulated solvents.