title: Enzymatic preparation of silybin phase II metabolites: sulfation using aryl sulfotransferase from rat liver.
abstract: Aryl sulfotransferase IV (AstIV) from rat liver was overexpressed in Escherichia coli and purified to homogeneity. Using the produced mammalian liver enzyme, sulfation-the Phase II conjugation reaction-of optically pure silybin diastereoisomers (silybin A and B) was tested. As a result, silybin B was sulfated yielding 20-O-silybin B sulfate, whereas silybin A was completely resistant to the sulfation reaction. Milligram-scale sulfation of silybin B was optimized employing resting E. coli cells producing AstIV, thus avoiding the use of expensive 3'-phosphoadenosine-5'-phosphate cofactor and laborious enzyme purification. Using this approach, we were able to reach 48 % conversion of silybin B into its 20-sulfate within 24 h. The sulfated product was isolated by solid phase extraction and its structure was characterized by HRMS and NMR. Sulfation reaction of silybin appeared strictly stereoselective; only silybin B was sulfated by AstIV.
authors.affiliation: Institute of Microbiology, Laboratory of Biotransformation, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 14220, Prague, Czech Republic.
authors.forename: Kateřina
authors.initials: K
authors.lastname: Purchartová
authors.forename: Leonie
authors.initials: L
authors.lastname: Engels
authors.forename: Petr
authors.initials: P
authors.lastname: Marhol
authors.forename: Miroslav
authors.initials: M
authors.lastname: Sulc
authors.forename: Marek
authors.initials: M
authors.lastname: Kuzma
authors.forename: Kristýna
authors.initials: K
authors.lastname: Slámová
authors.forename: Lothar
authors.initials: L
authors.lastname: Elling
authors.forename: Vladimír
authors.initials: V
authors.lastname: Křen
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D015239:Arylsulfotransferase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D008099:Liver / Q000201:enzymology; D051381:Rats; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D000077385:Silybin; D012838:Silymarin / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D011994:Recombinant Proteins; D012838:Silymarin; D000077385:Silybin; D015239:Arylsulfotransferase