| Abstract: | Two arginine-requiring mutant yeast strains grew on arginosuccinic acid or argininic acid in presence of ammonium sulphate but failed to do so on ornithine, citrulline or glycocyamine. The metabolic lesion in these mutants appears to lie therefore in the enzyme system involved in completing the guanidino group of arginine. Arginine could not be replaced by various peptides containing it. Histidine depressed growth on arginine of both the deficient yeast and its parent but growth was somewhat stimulated by certain other amino acids. To some extent the need for all amino acids was met by the use of hexamethylenediamine. |
