Abstract
In tissue cultures of C-57 black mouse heart and sarcoma T-241, beta-2-thienyl-DL-alanine acts specifically as a phenylalanine antagonist. Heart cultures can transaminate between beta-2-thienyl-DL-alanine and phenylpyruvate to form L-phenylalanine and thus block the toxic action of the remaining beta-2-thienyl-DL-alanine, whereas sarcoma T-241 cultures cannot. Of eleven mouse tumors and four rat tumors tested for their ability to perform this reaction, nine tumors had little or no activity. The beta-2-thienylpyruvic acid resulting from transamination further reacts to form a red compound the exact structure of which is not yet known.