176 E. F. Gale 



Fraction (b) shows that it consists of disrupted cells with a torn 

 outer wall and a greatly decreased content of electron-dense 

 material. This fraction constitutes the "disrupted cell 

 preparation" used for the work to be described. 



Properties of the disrupted cells 



The disrupted cell is non-viable and possesses no measurable 

 respiration but retains many of the enzymic and synthetic 

 activities of the intact cell. It can metabolize glucose with the 

 production of acid and can utilize hexosediphosphate as a 

 source of energy for protein synthesis. If provided with an 

 energy source and a complete mixture of the naturally 

 occurring amino acids, it can synthesize protein as shown by 

 increase in protein-nitrogen, in catalase and in glucozymase 

 activity; if galactose is also supplied, as inducer, it can 

 synthesize p-galactosidase although this enzyme is completely 

 absent in the initial preparation. If provided with a mixture 

 of purines and pyrimidines, including i^C-uracil, and a source 

 of energy, synthesis of ribonucleic acid (RNA) can be demon- 

 strated by incorporation of radioactivity into the RNA 

 fraction of the preparation, and this synthesis is increased by 

 the further addition of a complete mixture of amino acids. 

 As shown in earlier work with intact cells (Gale and Folkes, 

 19536), the synthesis of RNA is markedly increased by the" 

 presence of chloramphenicol at a concentration which limits 

 protein synthesis. 



When disrupted cells are incubated with a i*C-labelled 

 amino acid and a source of energy (normally ATP + hexose- 

 diphosphate), the labelled amino acid becomes incorporated 

 into the protein of the preparation. If the labelled amino acid 

 is one component of a complete mixture of amino acids 

 (condition 2), incorporation proceeds linearly for some hours 

 and is accompanied by measurable increase in protein. If the 

 labelled amino acid is the only amino acid present in the 

 incubation mixture (condition 1), then the rate of incorpora- 

 tion, which may initially be greater than that occurring in the 



