Intermediates in the metabolism of m-carboxy-substituted aromatic amino acids in plants. Phenylpyruvic acids, mandelic acids, and phenylglyoxylic acids.

Tracer experiments with 14C-labelled precursors in Iris times hollandica cv. Wedgwood, Reseda Iutea L. And Keseda Odorata L. have demonstrated that 3-(3-carboxyphenyl) alanine and 3-(3-carboxy-4-hydroxyphenyl) alanine can be derived from the corresponding pyruvic acids, presumably by unspecific transaminations, and that (3-carboxyphenyl) glycine and (3-carboxy-4-hydroxyphenyl) glycine can be derived from the corresponding phenylglyoxylic acids. The glycine derivatives are derived from the alanine derivatives, and the corresponding mandelic acids are intermediates in these transformations. The corresponding phenylacetic acids are incorporated only slightly into the glycine derivatives, indicating that oxidation at the benzylic position in the C6-C3 compounds takes place early in the transformation. The corresponding cinamic acids are not metabolized at all in the plants.