α-Aminoadipic Acid as a Constituent of a Natural Protein

Abstract

Thirty-five proteins or protein-containing materials were analyzed for α-aminoadipic acid by means of chromatography on starch columns. Of these materials corn and Taka-diastase (from Aspergillus oryzae) were shown to contain free α-aminoadipic acid. As a protein constituent aminoadipic acid was found in a water-soluble corn protein. Corn steepwater concentrate was an adequate source of this protein. α-Aminoadipic acid was shown to be a constituent of the protein by its isolation from hydrolysate. Its identity with the synthetic amino acid was proved by elementary analysis, mixed melting point, chromatographic behavior on both starch and Dowex-50 columns, use as a growth substance for a Neurospora crassa mutant which requires it for growth, and inhibition of growth by a specific inhibitor. The ionization constants for aminoadipic acid in water were determined. The conversion of radioactive α-aminoadipic acid into radioactive lysine in a mutant strain of Neurospora crassa was shown.