Flavonoid glucosylation by non-Leloir glycosyltransferases: formation of multiple derivatives of 3,5,7,3′,4′-pentahydroxyflavane stereoisomers

摘要: Flavonoids are known to possess a multitude of biological activities. Therefore, diversification the core structures is considerable interest. One nature's important tailoring reactions in generation bioactive compounds glycosylation, which able influence numerous molecular properties. Here, we examined two non-Leloir glycosyltransferases that use sucrose as an inexpensive carbohydrate donor, glycosyltransferase R from Streptococcus oralis (GtfR) and amylosucrase Neisseria polysaccharea (Ams), for glucosylation flavonoids. Flavones generally were poor substrates. Several inhibited Ams. In contrast, flavanes well accepted by both enzymes. All glucose attachments occurred via α1 linkages. Comparison three available stereoisomers 3,5,7,3',4'-pentahydroxyflavane revealed significant differences glycoside formation between them The latter shown largely complementary product ranges. Altogether, four hydroxy substituents terminal flavonoid rings glycosylated. Typically, Ams glucosylated B ring at position 3', whereas GtfR this 4' and/or A 7. several instances, short chains attached aglycones. These contained α 1-4 linkages when formed Ams, but 1-3 bonds generated GtfR. results show enzymes useful catalysts glucodiversification flavanes. total, more than 16 products formed, seven have previously not been described.