sj a 
17 
EFFECTIVENESS OF THE /-CATALASE. 
For the following tests a preparation of crude /-catalase was used 
which was obtained by salting out with ammonium sulphate a concen- 
trated cold-prepared extract of tobacco recently sweated in bulk. The 
precipitate, after being pressed between filter paper, was permitted to 
dry at the room temperature. A 1 per cent solution of this crude /- 
catalase, still containing a considerable amount of ammonium sulphate, — 
was prepared. One ce. of this solution'was mixed with 20 ce. of water 
and 2 ce. of common hydrogen peroxid (neutralized). The volume of 
oxygen evolved for different lengths of time was as follows: 
ee. 
PELE ey TEV UIOITGORE 5 et IRENE oe ok Ne Pe 12 
PelEer el OS eai pee ae ae ee ew ee elec Oe el oe ee 17 
A fier iG abba pen toe ge eee eee so fe hae are 
This result shows that in the dilution of 1:2,000 the crude enzym 
decomposed six times its own weight of anhydrous hydrogen peroxid 
in sixteen minutes. 
In the next test the reaction of the mixture was kept slightly alkaline 
and the amount of hydrogen peroxid increased to 10 ce., the other 
conditions being the same as before: 
ee. 
LOG SiMIItES 2. es = ag ee te Be iy ees oeee So ee) Foe ee ee 20 
jC) 7S ARO UIA TAUD) oo: ape Sc” Ne GS Dy lbees ype, ee ee CEOS 5 2 oS 38 
fk 2 EB Cie ta: a ee eee pe ee tl ET ee cree RRs 5d 
mater 40 tates <a 24 ee ee ee enue Ce sess Beas ae 76 
RRO IO TITTIES 6 ce re ese ts 9 See rene ers oy oe ae 80 
EES 1 eke ROUTE, 5) ss, 3 ean eR ed cg ON ae re. 2 ly > odeend NS 101.5 
In a further test 1 cc. of the 1 per cent catalase solution mentioned 
above was diluted with 200 ce. water and 1 cc. hydrogen peroxid 
added. One minute after the mixture was made the reaction for 
hydrogen peroxid was still very powerful.’ After twenty-five minutes, 
however, the reaction was very weak, and after thirty-two minutes 
there was no trace of hydrogen peroxid left. This test was repeated 
with the modification that the amount of water was increased to 500 
ec. and the amount of hydrogen peroxid decreased to 0.5 ce. After 
twenty-one minutes the reaction for hydrogen peroxid was very much 
weaker than in the beginning, and after fifty minutes no reaction at 
all was obtained. This shows that even in a dilution of 1: 50,000 the 
crude enzym was still very active. In the control case, where the. 
solution of the enzym was boiled for a second, the reaction for hydro- 
gen peroxid did not decrease to any noticeable degree within the same 
length of time. | 
While catalase attacks hydrogen peroxid very readily, the hydrogen 
peroxid also has, when applied in moderate concentration, a directly 
15253 2 
