1910] APPLEMAN—CATALASE 187 
acter of vegetable catalase. The size of the molecule of the latter 
prevents its passage through a Chamberland-Pasteur filter. 
Table IV also shows the effect of filtering and the necessity of 
thorough mixing of the extract before taking the sample for a 
total catalase determination. 
TABLE IV 
EFFECT OF FILTERING AND SETTLING 
cc. O, EVOLVED IN 30-SEC. PERIODS 
Tora cc. O, 
EXTRACT OF POTATO TUBER IN 3 MIN. 
Ist 2d 3d 4th 5th 6th 
Lege 2 Cat eee eer cere 12.219.5| 7.0] 5.0| 4.0 | 3.2 40.9 
hae aie liquid after settling| 5.4 | 4.5 | 3-5 | 3.0| ... |... 
20 min. later ..... 11.0 | 9-5 1.6.6 155-4.7 4 a 40.6 
Fier, hy min. la Ce Se AS | eey ee ee 10.3 
TABLE V 
EFFECT OF FILTERING THROUGH A CHAMBERLAND- Pagtete FILTER 
cc, O, EVOLVED IN 30-SEC. PERIODS 
Torat cc, O, 
EXTRACT OF POTATO TUBER 5 IN 3 MIN. 
st 2d 3d 4th 5th 6th 
A CS eee 24.8 |22.8 |19.3)|16.8 [14.8 |13.5 52. 
Rie aa eis egrets 6G pte poh ace °o. oO. Oo. °. 
Paras Ceeee es a5. 122.3 (10.3 116.7 |14.5 (13.5 51.6 
TEMPERATURE RELATIONS 
Catalases from different sources show considerable variation 
in temperature relations, the point of total destruction in the cases 
reported ranging from 65° C. to 80°C. In potato catalase, how- 
ever, destruction is complete when the temperature reaches 50° C. 
The Van’r Horr velocity coefficient for hemase has been found 
to be 1.5. The same figure applies to potato catalase, but is 
evident only from o to 10°. At 20° a destruction of the catalase 
begins, which renders the accelerating effect of higher temperatures 
upon the peroxid decomposition impossible of manifestation. 
3 The diminishing coefficient indicated in table VI is due to actual 
destruction of the catalase, as will be seen by table VII, which also 
Shows that the destruction at moderate. temperatures is not due 
