266 
MEASUREMENT OF THE CATALYTIC POWER OF CATALASE 
flask stood inside the thermostat and could be shaken from the outside by 
means of a handle. 
We obtained in normal cases a curve of the shape shown in figure 2. 
At A (fig. 2) the peroxide is in contact with the enzym; at B the reaction 
begins; at C the reaction is completed. The distance A-B existed always 
:B' B F Gr 
Fig. 2, For explanation see text. 
and was not caused alone by the transportation time of the pressure. The 
distance A-B became greater when we used smaller quantities of enzym. 
This fact, namely, that oxygen is not immediately discharged, is mentioned 
only by P. Waentig and A. Steche (/.^:.) With the use of the non-autographi- 
cal methods, and especially with that of the titration method, this fact 
nearly always escapes observation. We saw the latency time (A-B) 
manifested, when the titration method was used, only in dilute enzym 
solutions. The small bubbles of oxygen were formed sometimes one minute 
after the beginning of the reaction. It is clear, therefore, that the titration 
method not only is unfit to give us the end point of the reaction ; it is unfit also 
to give us the moment of the beginning. 
The differing length of A-B with different enzym dilutions gives us a 
hint that the decomposition is caused by two successive reactions (A. 
Bach^^), as follows: 
I. + 2A = 0-> 2A<0 - This unstable compound 
\Ohl decomposes : 
2A\^^ -> 2A<^^|^+ 2H2O This peroxide is decomposed: 
"\0H 
3. 2K( I -> 2A O + O2 Summing up, we obtain 
4. 2H2O2 -> 2H2O + O2 
22 Chem. Ber. 36-42. 1 904-1 908. 
