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Biocatalytic Generation of Molecular Diversity: Modification of Ginsenoside Rb 1 by β ‐1,4‐Galactosyltransferase and Candida antarctica Lipase, Part 4
Author(s) -
Gebhardt Steffen,
Bihler Stefan,
SchubertZsilavecz Manfred,
Riva Sergio,
Monti Daniela,
Falcone Laura,
Danieli Bruno
Publication year - 2002
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/1522-2675(200207)85:7<1943::aid-hlca1943>3.0.co;2-t
Subject(s) - chemistry , candida antarctica , stereochemistry , lipase , galactosyltransferase , glycoside hydrolase , ginsenoside , enzyme , disaccharide , glycoside , glycosylation , biochemistry , ginseng , medicine , alternative medicine , pathology
A series of specific derivatives of the complex protopanaxadiol glycoside ginsenoside Rb 1 ( 1 ) were prepared by catalysis of two unrelated enzymes: the β ‐1,4‐galactosyltransferase from bovine colostrum (GalT) and the lipase B from Candida antarctica ( Novozym ® 435 ). Both of the enzymes showed the expected regioselectivity towards specific glucose OH groups ( i.e. , OHC(4) for GalT and preferentially the primary OHC(6) for Novozym ® 435 ), accompanied by a nonpredictable ‘site selectivity' for the gentiobiose disaccharide unit linked at C(20) of the dammarane skeleton. The galactosylated products 1a – e and the acetylated products 1f – h were isolated by HPLC and fully characterized by extensive MS and NMR analysis.