I. Reactions of Phthaloylamino Acids: Modification of the Carboxyl Group of Amino Acid Derivatives. II. Derivatives of Indole 3-Carboxylic Acid. III. Metal Ion Complexes of Amidoximes: the Inhibition of the Alpha-Chymotrypsin Catalyzed Hydrolysis of

Various derivatives of α-phthalimido-β-phenylpropionic acid have been synthesized. starting from phenylalanine. The derivatives have a doubly bound nitrogen or sulfur atom in place of the carbonyl oxygen atom. The goal of the work was to prepare similar derivatives of other acylamino acids for evaluation as substrates in studies of α-chymotrypsin catalyzed hydrolysis. This has been accomplished in the case of the amidoximes, as exemplified by the preparation of L-α-acetamido-β-phenylpropionamidoxime. The preparation of this compound was accomplished by the use of a new method for cleaving the phthaloyl group, discovered during the present study. However, the above compound was not hydrolyzed by α-chymotrypsin at pH values ranging from five to nine. 3-Indolecarbonyl chloride has been prepared by an unusual method and used to acylate α-amino acid derivatives. The enzyme-inhibitor dissociation constant of α-chymotrypsin and L-α-acetamido-β-pheynylpropionamidoxime has been determined using nicotinyl-L-tyrosine hydrazide as the substrate.