22 
2e¢rams. Here the time required to produce 48 ce. of oxygen under 
otherwise the same conditions as before was noted. 
The number of minutes required to produce 48 cc. of oxygen in 
the presence of various salts was as follows: 5: 
: Minutes. 
Wath-sodiumchlorid: s<n.8 cat fe Saas eee eee pe he ka ec pretest 3 
HVathapotassmana: CLL: Si Fo so esky ec octeee ee yeteeee eee eee aes oe 
Wathzpotassimm: Nitrate. sis ee ees a eae ech aoa ee 43 
Math sodium sulphate: 2 2S i 2 a2 Seer ee ert ee ae a ee ee 3 
Watch potassium Sulphate 2 sie eee eo es yd See ete ea Bee pee ee 4 
PWath-codium carbonate (0:5 eran) <3. 525. ee 2 
Mithesodrum carbonate (2 onamis) == 9s. .0. 4 ee ere 4+ 
Wathout-addition-of salts=controle .< . 2228s 32 eee ee ee 3 
It will be noticed that potassium salts retard the reaction more than 
sodium salts, and that the nitrates of the alkali group retard more 
than the other salts. In general, the increase of the amount of any 
salt has a retarding influence, other things being equal, and it was 
found ina special case that saturation of the liquid with sodium chlorid 
retarded the action of the enzym so as to require more than double 
the time to produce the given amount of oxygen. 
Sodium carbonate (anhydr.) attacks 6-catalase but very slowly even 
ina3 per cent solution. Even after fifteen hours at low temperature 
the enzym is only partially killed. To a solution of which 20 ce. pro- 
duced 17.8 cc. of oxygen in fifteen minutes, 5 per cent of its bulk of 
sodium carbonate (anhydr.) was added in the form of a concentrated 
solution. After standing fifteen hours at 0° C. it was neutralized with 
acetic acid and, after the removal of the carbon dioxid by a current of 
air, 5 cc. hydrogen peroxid were added. There were still produced 
7.2 cc. oxygen in fifteen minutes. More injury is caused by heating _ 
the solution for one minute with 2 per cent of sodium carbonate to 
40° C, only 5 ec. oxygen being produced afterwards in fifteen min- 
utes. Scarcely any injury is observed after fifteen hours’ contact at 
15° C. with a1 per cent solution of sodium carbonate, and even after 
standing at the ordinary temperature for three days there is still con- 
siderable active enzym present in the solution. 
No injury whatever is caused in twenty-four hours by a 2 per cent 
solution of sodium fluorid or by a 5 per cent solution of dipotassium 
oxalate. Neither a 5 per cent solution of potassium sulpho-cyanide 
nor of thio-urea has any apparent injurious influence upon the /-cata- 
lase. The presence of these compounds seriously interferes, however, 
with the reaction of the enzym upon hydrogen peroxid, since potassium 
sulphocyanide is rapidly oxidized by hydrogen peroxid to mono- 
potassium sulphate and prussic acid,’ while thio-urea is transformed 
into sulphuric acid and (partly) carbamide.” ‘These mixtures rapidly 
1KCNS-+ 3H,0, = KHSO, + HCN + 2H,0. 
? CSN,H, + 4H,0, = SO,H, + CON,H, + 3H,0. 
ee 
* 
“ee ee 
5 Rie asl ne ee 
