In vitro Glucosylation of Dihydrojasmonic Acid and Abscisic Acid

Abstract

Cell-free extracts from cell suspension cultures of Lycopersicon peruvianum were found to catalyze the glucosylation of [U-³H]DJA and [2-¹⁴C]ABA in the presence of UDP-glucose. The products of enzymatic reactions were identified as glucosyl esters of DJA and ABA by means of TLC, HPLC and hydrolysis with cellulase. The two activities were not separated by ammonium sulfate fractionation and gel filtration, but the transferase activity of the enzyme was enriched toward radioactive DJA about 60-fold and toward radioactive ABA nearly 2-fold. A DJA metabolyzing enzyme was described for the first time and can be classified as UDP-glucose: DJA glucosyltransferase. In addition to the glucosyl esters of DJA and ABA the formation of further labelled products with still unknown structure were observed during the incubation.