Activation of Anthranilic Acid and N-Methylanthranilic Acid by Cell-free Extracts from Ruta graveolens Tissue Cultures

Abstract

Cell-free extracts of Ruta graveolens tissue cultures obtained after (NH₄)₂SO₄ precipitation and gel filtration on Sephadex G-25 catalyze the ATP-dependent activation of N-methylanthranilic acid according to the hydroxamate method. The rate of the enzyme reaction was shown to be linear for about 75 min and was proportional to the protein concentration up to at least 0.75 mg/ml of the enzyme preparation. This particular enzyme activity was only detectable in acridone alkaloid producing tissue cultures. Apparently activation of N-methylanthranilic acid is the second pathway-specific step in acridone alkaloid biosynthesis. It is not yet clarified if the activation takes place via the corresponding acyl adenylate or via phosphorylation.