Isolation and partial characterization of three glucosyl transferases involved in the biosynthesis of flavonol triglucosides in Pisum sativum L

The glucosyl transferases involved in the biosynthesis of flavonol-3-triglucosides in Pisum sativum L. have been further purified and characterized. The reaction sequence is as follows: Flavonol → flavonol-3-monoglucoside → flavonol-3-diglucoside → flavonol-3-triglucoside The reaction kinetics suggested the involvement of three distinct glucosyl transferases which could be demonstrated after elution of the enzyme preparation from DE-52 with a linear KCl gradient. Each enzyme has been characterized as to its pH optimum, stability, substrate specificity, and K m . The results obtained show that the synthesis of flavonol triglucosides in Pisum involves three distinct and highly specific enzymes, and the kinetic data present an explanation for the lack of accumulated mono- and diglucoside derivatives in vivo.