I. Thiocarbamate Studies. II. Preliminary Investigations of the alpha-Chymotrypsin Catalyzed Hydrolysis of Acylated Amino Acid Esters. III. The alpha-Chymotrypsin Catalyzed Hydrolysis of Methyl Hippurate and of Benzoyl-L-Valine Methyl Ester. IV. The Enzyme-Inhibitor Dissociation Constants of Some N-Acetyl Amino Acid N'-Methylamides

Citation

Applewhite, Thomas Hood (1957) I. Thiocarbamate Studies. II. Preliminary Investigations of the alpha-Chymotrypsin Catalyzed Hydrolysis of Acylated Amino Acid Esters. III. The alpha-Chymotrypsin Catalyzed Hydrolysis of Methyl Hippurate and of Benzoyl-L-Valine Methyl Ester. IV. The Enzyme-Inhibitor Dissociation Constants of Some N-Acetyl Amino Acid N'-Methylamides. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/03FF-7N17. https://resolver.caltech.edu/CaltechETD:etd-07082004-132616

Abstract

The known reactions of N,S-diphenylthiocarbamate were extended by studies of the effects of various reagents and conditions. The results are discussed in terms of previously suggested reaction mechanisms. The mixed anhydrides between S-phenylthiocarbonylchloride and carboxylic acids were briefly investigated as preparative intermediates. Low yields of the expected products offset the utility of this method. The non-reactivity of secondary amine S-phenylthiocarbamates was further demonstrated with N-pentamethylene-S-phenylthiocarbamate. The inert nature of this compound indicates that the effects are not due to steric hindrance. A brief investigation of the reactions of S-benzylthio- and 0-benzyl-N-phenylcarbamate suggest that they have little value as preparative intermediates as compared to the S- and 0-phenyl derivatives. Some S-phenylthiocarbamates of amino acid derivatives were prepared, and their use in a polymerization reaction and stepwise dipeptide synthesis is described. The results suggest that the various methods are not as elegant as indicated earlier. A recently developed automatic titration instrument was employed in a preliminary study of the [alpha]-chymotrypsin catalyzed hydrolysis of some acylated amino acid esters. A useable system was developed, and some preliminary results were obtained concerning techniques, data treatment, surface effects and steric effects in enzyme catalyzed reactions. The kinetics of the [alpha]-chymotrypsin catalyzed hydrolysis of methyl hippurate were re-investigated. In addition, the enzyme-inhibitor dissociation constants of two competitive inhibitors were re-determined. The results are compared with values obtained earlier. Benzoyl-L-valine methyl ester, a new substrate for this enzyme, was studied in the catalyzed reaction employing the above techniques. Additional refinements in technique and errors in this system are discussed. A number of potential competitive inhibitors, the N-acetyl amino acid N'-methylamides, were synthesized and tested for inhibitory activity in the [alpha]-chymotrypsin catalyzed hydrolysis of methyl hippurate and benzoyl-L-valine methyl ester. The results indicate that, of the compounds studied, only those containing an aromatic residue have a measurable effect in the present systems.

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