Ga wy So aS a Nee eT OES A ee Ss ee Sree ee 
5 a a ee 
1910] APPLEMAN—CATALASE 189 
this point. A fresh portion of 5 cc. of the extract, which had stood 
at the same temperature, was now allowed to act upon 6 cc. of 
hydrogen peroxid at the same time, with the result that approxi- 
mately the same amount of oxygen was evolved as the total pro- 
duced when 6 cc. were added in successive lots of 1 cc. each. The 
experiment was repeated several times with different extracts and 
dilutions, with practically the same result in every case. 
TABLE VIII 
CONSUMPTION OF THE CATALASE DURING THE REACTION WITH HYDROGEN PEROXID 
| . 
cc. O, EVOLVED WHEN H.O, WAS ADDED ToTAat cc. O, 
IN SUCCESSIVE LOTS OF I CC, EACH ToTaL | EVOLVED WHEN 
PoTaTO TUBER EXTRACT . O CC. WERE 
= EVOLVED ADDED IN 
1st 2d | 3d 4th | .5th 6th 
| i 
500, Gxtranie . cot wet Oe | O08.) Oe) bg 4 oO ee 31.6 
3 CG Sate Oxiacr: fc oP hee a bea ee as 31.8 
The destruction or degeneration of the catalase would be slight 
during the time of the experiment in the above dilute neutral 
solution at 20°. Admitting a slight destruction, it would be the 
same in both cases, and would therefore not affect the general 
result. Kastie (7) suggests that catalases, like peroxidases, may 
combine with the hydrogen peroxid to form an unstable holoxid 
derivative, as K+H,0,=H,KO,. This might in turn oxidize the 
catalase itself (K) which may be more readily oxidizable than any 
of the peroxidase reagents, in which event we would have H,KO,= 
H.0+KO. This conception is in striking harmony with the facts 
indicated in the above table, and with the fact that the reaction 
is decidedly an exothermal one. 
RELATION TO FUNCTIONAL ACTIVITY 
There is considerable evidence from animal tissues that catalase 
activity bears a relation to functional activity of the structure. 
Such a relation seems to exist in the potato, at least in respect to 
Tespiratory activity. Extracts from potatoes which have been 
kept for several days at o° C. show a decided decrease in catalase 
activity. Mizier-Taurcav (8) has also shown that respiration 
'S greatly reduced in such potatoes. 
