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Studies on the Mode and Mechanism of Action of alpha-Chymotrypsin


Bernhard, Richard Allan (1955) Studies on the Mode and Mechanism of Action of alpha-Chymotrypsin. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/CPFB-ZF49.


NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The enzyme-inhibitor dissociation constants, i. e. , K[subscript I] values, for alpha-chymotrypsin and two competitive inhibitors, indole-2-carboxylate and cinchoninamide, have been determined at pH 7. 9 and 25[degrees]. A new colorimetric procedure for the determination of proteolytic activity employing the reaction of ninhydrin with ammonia has been developed. A study has been made of the effect of buffer species and ions upon the course of alpha-chymotrypsin catalyzed hydrolyses. It has been demonstrated for the case at hand that K[subscript S] is essentially independent of buffer species and ionic strength. The discrepancies between values of k[subscript 3], evaluated in the presence of THAM-HCl buffers and in the presence of phosphate buffers, appear to be due principally to the effects of the increased ionic strength of the phosphate buffers. A number of enzyme-inhibitor dissociation constants have been evaluated in different buffer systems. During the evaluation of K[Subscript I] values for anionic, bifunctional, competitive inhibitors of alpha-chymotrypsin, it was determined that the presence of phosphate buffers apparently increased the affinity of the enzyme for the inhibitor. A possible mechanism for this phenomenon has been proposed and has been supported by experimental observations. It has been demonstrated that in a typical alpha-chymotrypsin catalyzed hydrolysis, the reaction proceeds in solution insofar as can be experimentally determined, and that wall effects are unimportant within the limits of experimental error. An investigation has been made of the possible use of dilatometry as a means of following the course of enzyme catalyzed hydrolyses. A number of instruments have been developed and discussed. Some typical data have been experimentally determined and analyzed in the usual manner.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Chemistry and Plant Physiology)
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Minor Option:Biology
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Niemann, Carl G. (advisor)
  • Bonner, James Frederick (co-advisor)
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1955
Record Number:CaltechETD:etd-11212003-114338
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:4619
Deposited By: Imported from ETD-db
Deposited On:21 Nov 2003
Last Modified:28 Jun 2023 17:57

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PDF (Bernhard_ra_1955.pdf) - Final Version
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