1905] DEAN—PROTEOLYTIC ENZYMES 337 
The ereptase solution obtained from A gave a weak biuret reaction 
and a faint coagulum on heating. Attempts to precipitate the enzyme 
by means of uranium acetate according to Jacoby’s method failed; 
no precipitate was obtained except in acid solutions in which the 
enzyme was destroyed. The ereptase was tested with crystallized 
edestin from hemp seed, crystallized excelsin from the Brazil nut, 
phaseolin from the bean, boiled fibrin, and Witte peptone. The 
native proteids were all unattacked and the Witte peptone was 
actively digested. 
An ereptase solution was prepared from 15008" of bean meal by 
extraction with water, filtering the extract, half saturating the solution 
with ammonium sulphate, and dialyzing the solution obtained from 
this half saturation precipitate. A perfectly clear solution resulted 
after filtering off the phaseolin precipitated by dialysis, and this 
was dried at 4o to 50° C., yielding 2.98™ of a golden yellow powder. 
This powder was found to be active in digesting Witte peptone, 
although it seemed that the purification and drying had considerably 
diminished the power of the enzyme. This protease preparation was 
tested with some of the fractions of Witte peptone which had been 
separated by Picx’s'® method and with a preparation of phaseolin. 
The first experiment was carried out using the secondary protease 
preparations without the removal of the ammonium sulphate left 
adherent by the method of separation. 
One and one-half grams of the enzyme preparation mentioned 
above were dissolved as completely as possible in 300°° of water, 
35°° of this solution measured into each of five flasks, and 2°° of toluol 
added. Proteids were added as follows: 
No. 1—18™ of phaseolin. 
No. 2—18™ of proto-proteose. 
No. 3—18™ of hetero-proteose. 
No. 4—18™ of secondary albumose A. 
No. 5—18™ of secondary albumose B. 
After shaking, 1 5°° were removed from each flask, 15°° of tannic 
acid reagent added, and the precipitates filtered off. Analyses of 
to** of each filtrate were made in duplicate: 
No. 1—required 0.7°¢ of standard acid. 
No. 2—required 0.6° of standard acid. 
*® Pick, Zeitschr. Physiol.-Chem. 24:246. 1898. 
