Plant secondary products, which include the flavonoids, have a variety of roles in plant systems. Their roles include biosignalling, UV protection, antifeedant activity, pollinator attraction, stress response, and many others. Glucosylation is an important modification of many flavonoids and other plant secondary products. In grapefruit, glucosylation is important in the synthesis of the bitter compound naringin. Glucosyltransferases catalyze glucosylation reactions. Putative plant secondary product glucosyltransferases may be identified by the loosely conserved “PSPG box” amino acid sequence; however, with current knowledge, biochemical characterization is the only way to determine with certainty the function of these enzymes. The hypothesis tested here is that PGT11 is a plant secondary product glucosyltransferase. Recombinant PGT11 has been expressed in yeast using the pPICZ A vector. To investigate the hypothesis, the enzyme will be screened for glucosylation activity with various flavonoid and phenolic substrates.
Available at: http://works.bepress.com/cecilia-mcintosh/61/