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The binding and catalytic properties of lysozyme

Citation

Dahlquist, Frederick Willis (1969) The binding and catalytic properties of lysozyme. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/WEXB-9D59. https://resolver.caltech.edu/CaltechTHESIS:01292016-143302044

Abstract

The binding and catalytic properties of hen's egg white lysozyme have been studied by a variety of techniques. These studies show that the enzyme has three contiguous binding subsites, A, B, and C. The application of nuclear magnetic resonance (NMR) spectroscopy to probe the binding environment of several saccharides to lysozyme has demonstrated that the reducing end sugar rings of chitotriose, chitobiose and the β-form of N-acetylglucosamine all bind in subsite C. The central sugar ring of chitotriose and the sugar ring at the nonreducing end of chitobiose were found to bind in subsite B, while the nonreducing end sugar residue of chitotriose occupied subsite A. The dynamics of the binding process has also been investigated by NMR. The formation rate constant of chitobiose--and chitotriose-enzyme complexes were found to be about 4 X 10-6 M-1 sec-1 with small activation energies.

The stereochemical path of the lysozyme catalyzed hydrolysis of glycosidic bonds has been shown to proceed with at least 99.7% retention of configuration at C-1 of the sugar. The lysozyme catalyzed hydrolysis of glucosidic bonds has been shown to be largely carbonium ion in character by virtue of the α-deuterium kinetic isotope effect (kH/kD = 1.11) observed for the reaction. It is probable that the mechanism of action of the enzyme involves a carbonium ion intermediate which is stereospecifically quenched by solvent. However, acetamido group participation cannot be ruled out for natural substrates.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Chemistry
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Raftery, Michael A.
Thesis Committee:
  • Unknown, Unknown
Defense Date:25 September 1968
Funders:
Funding AgencyGrant Number
NIHUNSPECIFIED
CaltechUNSPECIFIED
Record Number:CaltechTHESIS:01292016-143302044
Persistent URL:https://resolver.caltech.edu/CaltechTHESIS:01292016-143302044
DOI:10.7907/WEXB-9D59
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9552
Collection:CaltechTHESIS
Deposited By: Leslie Granillo
Deposited On:02 Feb 2016 16:20
Last Modified:21 Dec 2019 01:32

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