I. The consequences of systematic error in enzyme kinetics. II. L-tyrosyl-L-tyrosine derivatives for the detection of transpeptidation in alpha-chymotrypsin-catalyzed hydrolyses. III. The interaction of alpha-methyl-alpha-acylamino acids with alpha-chymotrypsin. IV. The apparent ionization constants of a series of phenylalanine derivatives

by Almond, Harold Russell

Abstract (Summary)
NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The consequences of systematic error in enzyme kinetics were investigated. Systematic error in substrate blank, enzyme blank, velocity determination, substrate concentration and the Beer-Lambert relationship was considered. The advisability of using weighting procedures in the presence of systematic error was questioned. L-Tyrosyl-L-tyrosine methyl ester, amide, hydrazide and hydroxamide were prepared in order to detect transpeptidation in alpha-chymotrypsin-catalyzed hydrolyses. The reaction products from the hydrolyses of the corresponding L-tyrosine derivatives were found to contain only negligible amounts of transpeptidation products except for L-tyrosinhydroxamide which gave some L-tyrosyl-L-tyrosine. alpha- and beta-chymotrypsin were qualitatively the same with respect to these reactions. The N-acetyl methyl esters of alpha-methylphenylalanine, alpha-methyltyrosine and alpha-methyl-beta-(2-naphthyl)-alanine were synthsized and resolved. These esters are good competitive inhibitors of alpha-chymotrypsin. N-acetyl-(-) alpha-methyl-beta-(2-naphthyl)-alanine is a slowly hydrolyzed substrate of this enzyme. The inactivity of these esters toward alpha-chymotrypsin-catalyzed hydrolysis is a consequence of their inability to react further after complexing with the enzyme. The [...] values of the alpha-ammonium groups of D,L-phenylalanine amide, thioamide, amidoxime, hydrazide, methyl ester and hydroxamide were determined. Comparison of these [...] values with some for corresponding glycine derivatives shows the former to be 0.59 ± .04 pK units lower. The infrared spectra of these phenylalanine derivatives were determined in KBr.
Bibliographical Information:

Advisor:Carl Niemann

School:California Institute of Technology

School Location:USA - California

Source Type:Master's Thesis



Date of Publication:01/01/1961

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