Site-selective glycosylation at position 166 at the base of the primary spe
cificity S-1 pocket in the serine protease subtilisin Bacillus lentus (SBL)
created glycoproteins that are capable of catalyzing the coupling reaction
s of not only L-amino acid esters but also D-amino acid esters to give the
corresponding dipeptides in good yields as a result of greatly broadened su
bstrate specificities that can be rationalized by the interaction of the gl
ycans acting as chiral auxiliaries in stereochemically mismatched pairs.