349 



1. IruJigo/eni. 



2. Phajiis. 



3. Polygonum. 



4. Sacchaioinvces 



sphatriciii. 



=;. Emuhi)ie. 



20 



30 



40 



50 55 57 60 65 67 70 75 80° C 



For aethyl-acetate-yeast the optimum lies at 44", for Fhajiis at 53" C, and for 

 emulsine at 55" C.^). 



Particularly for emulsine the intensity of action is feeble, and the feebier it is, 

 the more troublesome exactly to fix the temperature-optimuni, as is clearly shown by 

 the course of the curved line in the graphic representation. 



For the exact determination of the shape of the curved line uhich indicates the 

 general relation between decomposition and temperature, temperatures above and 

 below the optimum were sought, at which the quantities of indigo, formed after an 

 hour's action, were quite the same. In a system of coordinates with the temperatures 

 as abscisses and the intensity of decomposition as ordinates, these points have tht-n 

 equal ordinates and by determining some such couples the whole course of the curve 

 becomes known. When looking at the curves found in this way we see that the 

 decrease of action abuve the optimum is much more rapid than the rising below and 

 that the last rising is not proportioned to the temperature. 



At the same temperature the indican-decomposition by the various enzymes is 

 operated with very unequal intensity. Proportionate ciphers between them were fixed 

 as follows. In the experiments described before, so much of the enzymes to be 

 compared was added to 10 cc. of indican-solution that at the optimum temperatures 

 effects of equal intensity were observed. This proved to bc the case when use was 

 made of the following quantities of crude enzyme in milligrams: hidigofera 5, Poly- 

 gonum 20, Saccharomyces sphaerictis 40, emulsine 100, whicli nunibers stand to one 

 another as i : 4 : 8 : 20. When all these quantities were doubled or reduced to the 

 half, the proportions underwent 110 change. Consequently from these numbers follows 

 that the intensity of decomposition for the different enzymes is expressed thu?: 



') As is seen, the difiference Ix-twccn the optiintnn .-ind mrixinuini tciniUTatiirc is 

 for all enzymes about 14° C. 



