Feeding Experiments With Mixtures of Highly Purified Amino Acids

The hitherto unknown growth essential has been isolated in pure, crystalline form, san indentified as one of the four optically isomeric α-amino-β-hydroxy-n-butyric acids. Several of its derivatives have been prepared and described. On reduction of new amino acid yields d-α-amino-n-butyrie acid. The spatial configuration around the β-carbon atom remians to be determined, and is now being investigated. With an otherwise adequate diet, appromiately 0.6 per cent of α-amino-β-hydroxybutyric acid is the minimum amount necessary to induce maximum growth. The feeding trails herein described constitute the first successful attempt to rear animals on a ration contraining purified a mino acids as the sole source of nitrogen. Inasmuch as satisfactory growth has been secured by the use of diets devoid of hydroxyglutamic acid and citruiline, these two amino acids are not indispensable components of the food. Experiments designed to determine the physological importance of the remaining amino acids are now under way.