5. Tryptophane and niacin assays.
Assay of tryptophane by a chemical method and by the use of Lactobacillus arabinosus and Streptococaus faecalis gave very similar results (82, 80, and 79 micrograms/sample) for a pure protein sample using enzyme hydrolysis; however on corn samples the values obtained with L. arabinosus were higher than those with S. faecalis. Eight developmental stages of su KYS averaged 17% higher with L. arabinosus and a corresponding series of KYS averaged 18% higher. This points to the presence in corn of substances that assay as tryptophane with the less exacting organism but are not tryptophane.
Anna C. Newton and H. J. Teas