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 × hollandica cv. Wedgwood, Roseda lutea L. and Reseda 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 trans-aminations, and that (3-carboxyphenyl)glycine and (3-carboxy-4-hydroxy-phenyl)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 cinnamics acids are not metabolized at all in the plants.     

Ligand-exchange chromatographic resolution ofDl-amino acids in the presence of nucleic acids

Summary Nine representativeDl-amino acids were resolved using ligand-exchange chromatography whose mobile phase containe Cu (II) and ribonucleic acids. It was also found that deoxyribonucleic acids could be substituted for RNAs. In the presence of 5-GMP, 4XMP, (a mixture of 5-GMP,-AMP,-CMP, and-UMP), and oligomer of RNA,L-amino acids, which seemed to give more stable complexes, were eluted more slowly than the opposite isomers.     

The reactions of the sulfur-containing amino acids with phosphoric and sulfuric acids

Both cystine and cysteine react very differently toward 6.0 M phosphoric and sulfuric acids. With phosphoric acid, extensive decomposi tion occurs; with sulfuric acid, very little.Cystine, in phosphoric acid at 100 °C. produces hydrogen sulfide, free sulfur, cysteic acid, ammonia, alanine, serine, and pyruvic acid. Cysteine produces a similar series but with marked quantitative differences.Cystine, in sulfuric acid, is merely racemized.Methionine is largely demethylated by sulfuric acid under these conditions. It is practically inert toward phosphoric acid.The behavior of hair toward phosphoric and sulfuric acids is similar to that of cystine but is modified by reactions of other hydrolytic products.