Metabolism of 14C-indole-3-acetaldoxime by hypocotyls of Chinese cabbage

The metabolism of ¹⁴C-indole-3-acetaldoxime by Chinese cabbage hypocotyls was investigated using labelled tracer and incubation times less than 1 hr. Indole-3-acetonitrile, indole-3-methylglucosinolate and desulpho-indole-3-methylglucosinolate were the major metabolites, while IAA or other IAA precursors were not detected. The kinetics of the conversion of the aldoxime to the three metabolites was different under continuous feeding and pulse feeding conditions. The apparent K_m for the conversion of the aldoxime to the nitrile and the glucosinolate were 3.3 and 5.0 μM, respectively. Tissues of Isatis tinctoria, Helianthus annuus and Zea mays also formed significant amounts of the nitrile and Zea mays formed small amounts of indole-3-acetaldehyde.