BIOSYNTHESIS AND GENETIC-CONTROL OF ISOVITEXIN 2''-O-ARABINOSIDE IN PETALS OF SILENE-DIOICA

In petals of Silene dioica plants, an enzyme has been demonstrated which catalyses the transfer of the arabinose moiety of UDP-arabinose to the hydroxyl group on the 2″-position of the carbon-carbon bound glucose of isovitexin. The presence of this arabinosyltransferase activity is controlled by the dominant allele glA. Maximal activity takes place at pH 7.2-7.5; the reaction is stimulated by the divalent metal ions Mg and Mn. For optimal solubilization of the enzyme, Triton X-100 is necessary. Substrate specificity and kinetic behaviour have been investigated. © 1979.