THE UTILIZATION OF PHENYLALANINE AND TYROSINE DERIVATIVES BY MUTANT STRAINS OF ESCHERICHIA COLI

The production of several mutant strains of Escherichiu coEi which require for growth an exogenous source of particular amino acids (1) has made possible a study of the manner in which individual mutants can use pcptides and other amino acid derivatives for growth. In the present c~ommunioat,ion, data are presented on the utilization of derivatives of phcnylalanine and tyrosine by appropriate mutants of Escherichia ccli.