326 H. B TAYLOR. 
in all cases kept at the required temperature five minutes 
before the hydrogen peroxide was added. 
Table VII. 
Concentration of hydrogen peroxide = M/300. K = ae log 
t a-— x 
C tration of = | = 2? jog eae 
oncentration: of enzyme. — 1 taf: cee 
© 4 4 H.O, decomposed 
Temperature ° C. K x10 K, x10 in thirty sale 
0 22 41 1-2 
15 39 80 2°0 
26 66 152 2°4 
35 51 482 2°05 
50 42 842 1°30 
It will be seen that as the temperature increases, a 
maximum figure is reached in the value of A showing that. 
the optimum temperature, taken for one-third of the reac- 
tion, was in the vicinity of 25° C. When the end point of 
the reaction is taken into consideration the figures for the: 
velocity constant A, show no maximum, but increase in a 
regular way similar to that of a reaction catalysed by an 
inorganic catalyst, as shown in the last column of the above: 
table. The reason why there is no maximum in the value 
of X, is that the destruction of the enzyme is very greatly 
increased with rise of temperature, thus making the period 
of the reaction much less. By decreasing the period of 
the reaction and the total amount of hydrogen peroxide 
decomposed so that C,, becomes greater, the ratio C,- C, 
: C.-C, in the formula 
ren’ hee HO 
becomes greater and consequently the values of A, are 
greatly increased. This increase in the value of 4, is large 
enough to obscure the decrease owing to the inactivation 
of the enzyme. 
