BY MEANS OF CATALYSTS. CKE1GHTON. 



31 



poisons. The poisonous influence of many substances- towards 

 inorganic catalysts has been thoroughly investigated by Bredig 

 and his pupils in the last few years. The effect of a number of 

 different poisons on inorganic catalysts and enzymes is illus- 

 trated in the accompaning table, in which is shown the con- 

 centration of the different poisons that is necessary to entirely 

 destroy the catalytic influence of colloidal platinum 1 and of 

 catalase 2 011 hydrogen peroxide: 



That enzymes exhibit a stereocJiemical specificity has long- 

 been known. The principle here involved is that one of the 

 antipodes 1 of the substrate is changed much quicker by the 

 enzyme than the other, which very often remains practically 

 unchanged. Pasteur 3 observed, for instance, that with racemic 

 ammonium tartrate only the dextro antipode was attacked by 

 mould enzyme (penicillium glaucum), the solution becoming 

 laevo-rotatary. Our fundamental knowledge in this field, how- 

 ever, is due to the researches of E. Fischer. He has shown 

 that a particular enzyme is able to attack certain stereochemical 



1. Bredig, G., and Muller v. Berneck: Zeit. f phys. Chem., 31, 258, 

 (1899). 



2. Senter, G.: Zeit. f. phys. Chem., 44, 257, (1903). 



3. Pasteur: Compt. rend., 51, 298, (1860). 



