I. Investigations of the Alpha·Chymotrypsin Catalyzed Hydrolysis of Amino Acid Hydrazides. II. Synthesis of Amino Acid Derivatives. III. The Apparent Ionization Constants of a Series of Phenylalanine Derivatives

Citation

Kerr, Richard John (1957) I. Investigations of the Alpha·Chymotrypsin Catalyzed Hydrolysis of Amino Acid Hydrazides. II. Synthesis of Amino Acid Derivatives. III. The Apparent Ionization Constants of a Series of Phenylalanine Derivatives. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/AXT0-NZ95. https://resolver.caltech.edu/CaltechETD:etd-07202004-112555

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The effect of variation in the concentration of tris-(hydroxymethyl)-aminomethane buffer systems upon the kinetic constants of the alpha-chymotrypsin catalyzed hydrolysis of nicotinyl-L-tyrosinhydrazide has been determined at pH 7.9 and 25.0[degrees]C. This study indicates a linear relationship between the logarithm of values of [...] and the square root of the ionic strength. It has been demonstrated, in the case of the hydrazide investigated, that the value of the Michaelis-Menten constant, [...], is independent of the variations applied. A confirmation of the activating influence of calcium ion has been made. An increase of approximately 75% in the initial velocity of the alpha-chymotrypsin catalyzed hydrolysis of nicotinyl-L-tyrosinhydrazide is noted upon the addition of [...] calcium ion to the reaction system. The colorimetric determination of hydrazine employed to determine the extent of hydrolysis in the above cases has been reinvestigated. A reinvestigation of the kinetics of the alpha-chymotrypsin catalyzed hydrolysis of acetyl-L-tyrosinhydrazide utilizing improved procedures of analysis indicated above has been made. The possibility of observing product inhibition depending upon values of initial substrate concentration and [...] is discussed. The preparation of acetyl-, benzoyl-, trifluoracetyl-, and methanesulfonyl-DL-phenylalanine salicylamide esters is described. Several attempts to synthesize the optically active esters are described. Reasons for racemization in the cases tried are briefly discussed. During the course of attempted dehydration procedures with polyphosphoric acid several interesting dehydrocyclination products are isolated and described. The preparation of trifluoracetyl-L-phenylalanine anthranilamide is described. The synthesis of acetyl-DL-phenylalanine glycolamide and acetyl-L-phenylalanine glycolamide are described. Preliminary investigations were conducted in the alpha-chymotrypsin catalyzed hydrolysis of the above compound. The apparent ionization constants of the protonated amino group of a series of DL-phenylalanine derivatives have been determined. The expected differences in the pK of these derivatives due to changes in acid derivative were not realized except in the case of phenylalanine hydrazide. The use of an automatic pH titration and recording instrument is described.

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