Biochemical and characterization of glycosyltransferases from red sweet cherry ( L.) reveals their broad specificity toward phenolic substrates.

Polyphenolic compounds are a class of phytonutrients that play important roles in plants and contribute to human health when incorporated into our diet through fruit consumption. A large proportion occur as glycoconjugates but the enzymes responsible for their glycosylation are poorly characterized. Here, we report the biochemical and structural characterization of two glycosyltransferases from sweet cherry named UGT1 and UGT2. Both are promiscuous glucosyltransferases active on diverse anthocyanidins and flavonols, as well as phenolic acids in the case of UGT1. They also exhibit weaker galactosyltransferase activity. The expression of the gene encoding UGT1, the most active of the two proteins, follows anthocyanin accumulation during fruit ripening, suggesting that this enzyme is the primary glycosyltransferase involved in flavonoid glycosylation in sweet cherry. It can potentially be used to synthesize diverse glycoconjugates of flavonoids for integration into bioactive formulations, and for generating new fruit cultivars with enhanced health-promoting properties using breeding methods.