Induction of hydroxyanthranilate hydroxycinnamoyl transferase activity by oligo-N-acetylchitooligosaccharides in oats

Article abstract of DOI:10.1016/S0031-9422(98)80055-1

An assay method for hydroxycinnamoyl-CoA: hydroxyanthranilate N- hydroxycinnamoyl transferase (HHT) in oat leaves (Avena sativa L.), which is thought to be one of the key enzymes for the biosynthesis of avenanthramides, phytoalexins in this plant, was established. HHT activity was induced by treating the leaves with oligo-N-acetylchitooligosaccharides. Among the chitooligosaccharides tested, penta-N-acetylchitopentaose ((GlcNAc)₅) was the most effective in inducing activity. The induction by (GlcNAc)₅ was dose-dependent, in which case HHT activity was initially detected after 6 hr and reached a maximum by 12 hr. All of the putative precursors of avenanthramides acted as substrates for HHT, with 5-hydroxyanthranilic acid and feruloyl-CoA being the best substrates for the anthranilic moiety and the cinnamoyl moiety of avenanthramides, respectively.