CATALASE REACTION OF MILK. 329 
Table X. 
Concentration | m y amount LO 
of hydrogen frees KX 1074 | X10? | Ke 104 decomp. t i es 
peroxide. 
M/300 0 29 rl 103 | 9:40 
15 39 80 950 | 8:35 
25 66 152 552 7-35 
35 51 482 6,267 2-50 
50 42 842 21,260 1°35 
From the above figures it will be seen that the rate of 
destruction at 50°C. is over 200 times as fast as it isat 0° C., 
and even as low as 15° C. it is two and a half times as fast 
asat0° ©. The amounts of hydrogen peroxide decomposed 
are measured in ccs. N/400 permanganate solution. The 
value for the temperature coefficients calculated in the 
same way as for the decomposition of hydrogen peroxide 
by the enzyme (Table VII), are given in the following table. 
Table XI. 
Kx X 10+ Temperature ° C. Temp. Coefficient 10° C. 
103 0 Oy es le 
250 1d On 2a; — 1-9 
552 25 Loe) D2 
6267 a 25 — 35 = 11:4 
21260 | 50 25 — 50 = 4:3 
JOO) me 
From the above it is seen that the temperature at which 
the greatest increase in the rate of destruction takes place - 
corresponds with the temperature at which the velocity 
constant A begins to decrease. 
Effect of potassium cyanide on K and Ky. 
The catalase solution used in the following experiments 
was prepared by dialysing an aqueous solution of the 
