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 activitiy was induced by treating the leaves with oligo-N- acetylchitooligosaccharides. Among the chitooligosaccharides tested, penta-N- ...