[On demethylation and decarboxylation of benzoic acids in plant cell suspension cultures].

Various benzoic acids (14)C-labelled in para and meta methoxyl groups as well as (O-methyl-(14)C) p-methoxy cinnamic acid were tested for O-demethylation in cell suspension cultures of Phaseolus aureus Roxb. and Glycine max Merr. On the basis of (14)CO2-formation and product analyses the O-demethylation reactions were shown to be specific for para methoxyl groups. A vanillate-O-demethylase known from microbial sources seemed to be absent in the plant cell cultures.In this and in an earlier publication (Berlin et al., 1971) some twenty (14)C-labelled aromatic compounds were tested for catabolic reactions in the cell cultures, and here we report on the product analyses and the general pattern of distribution of radioactivity. Finally, some indications for compartmentalisation in connection with catabolic studies of aromatic compounds in plant cell cultures are discussed.Decarboxylation of substituted benzoic acids in the cell cultures is restricted to aromatic acids possessing a hydroxyl group in the para position. Only trace amounts of labelled CO2 were released from (carboxyl-(14)C)-anisic acid. This acid, however, was nearly quantitatively demethylated to p-hydroxybenzoic acid, which itself was decarboxylated to a considerable extent after being fed to cell suspension cultures. Similar differences in respect to decarboxylation were observed with syringic acid produced by demethylation of trimethoxybenzoic acid and syringic acid applied directly to the cell cultures.