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The Enzymes which are Concerned in the Decomposition of Glucose 

 and Mannitol by Bacillus coli communis. 

 By Egeeton Charles Grey, 1851 Exhibition Scholar. 



(Communicated by Dr. A. Harden, F.E.S. Eeceived February 19, — Eead 



March 26, 1914.) 



(From the Biochemical Department of the Lister Institute.) 



By the cultivation of bacteria in the presence of certain substances, for the 

 most part toxic in character, it is possible to obtain strains in which the 

 fermentative powers differ considerably from those of the parent organisms. 

 As an example may be taken a variety of B. coli communis (Escherich) which 

 was produced by the growth of that organism on agar containing sodium 

 chloroacetate (see Penfold, 1911). This strain differed from the parent strain 

 in that it now decomposed glucose with the production of acid but not of gas. 



This result pointed to two possibilities ; firstly the decomposition of glucose 

 by the selected strain might be brought about by a set of ferments, which 

 acted very differently from those of the normal strain responsible for the 

 decomposition of the same substance, or secondly the primary cleavage 

 products of glucose might be the same both from the original and the 

 selected strain, and the difference between the action of the two might 

 depend upon some secondary process, as for example the decomposition of 

 formic acid, through which, as Pakes and Jollyman (1901) and Harden 

 (1901) have shown, the carbon dioxide and hydrogen most probably arise. 



It is obviously of great biological importance to know whether the changes 

 brought about by growth on sodium chloroacetate result in any profound 

 modification in the carbohydrate metabolism of the organism. It was, at the 

 outset, considered most probable that those enzymes which were responsible 

 for the cleavage of the glucose molecule into its primary products would be 

 less likely to be lost than those which brought about the secondary changes. 



It was hoped, therefore, that by a comparison of the products formed from 

 glucose and mannitol by the normal organism with those produced from the 

 same substances by the artificially modified strains it would be possible to 

 determine how many different enzymes were concerned in the process. 



If a number of products are formed by one enzyme the ratio which they 

 bear to one another should not be altered by the process of selection, or 

 conversely if on selection the ratio between any two substances is found to 

 alter it may be taken as evidence that these two substances are not produced 



