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The Effect of Urea on Cofactor Requiring Bacteriophage


Sato, Gordon Hisashi (1956) The Effect of Urea on Cofactor Requiring Bacteriophage. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/ZQTH-RJ42.


Some strains of bacteriophage must be activated by cofactor before they can adsorb to their bacterial hosts. Up to the present time, the only compounds shown to possess cofactor activity have been certain amino acids and amino acid analogues. In the present study, it is shown that urea, a well known denaturing agent, is capable of activating cofactor requiring phage. By a process, statistically independent of the activation process, urea also kills the phage. Experiments are performed to characterize the properties of urea-activated phage, in regard to stability of urea induced adsorbability and in regard to adsorption rate. The kinetics of the urea activation process and of the urea killing process are studied in detail. Both processes are shown to depend on concentration of urea, temperature, and pH in a manner similar to denaturation of protein by urea. It is concluded that urea effects the activation of phage by denaturing the protein of the phage adsorption organ. It is further postulated that the action of cofactors consists in a denaturation of phage protein. The biological implications of this hypothesis are discussed.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Biophysics and Physics)
Degree Grantor:California Institute of Technology
Major Option:Biology
Minor Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Delbruck, Max
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1956
Additional Information:Title in 1956 Caltech commencement program varies: Effect of Urea on Co-Factor Requiring Phage
Record Number:CaltechETD:etd-04292005-085816
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1545
Deposited By: Imported from ETD-db
Deposited On:29 Apr 2005
Last Modified:11 Aug 2023 18:46

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