The Effect of Urea on Cofactor Requiring Bacteriophage

Citation

Sato, Gordon Hisashi (1956) The Effect of Urea on Cofactor Requiring Bacteriophage. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/ZQTH-RJ42. https://resolver.caltech.edu/CaltechETD:etd-04292005-085816

Abstract

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.

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