1905] DEAN—PROTEOLYTIC ENZYMES 331 
CucuRBITA MAxIMA.—The seeds of this plant and the young 
seedlings with radicles an inch and a half long were found to contain 
an ereptase of considerable power as shown by the action of their 
tissues on Witte peptone. Under conditions for autolysis none 
seemed to take place, since no tryptophan reaction was obtainable, 
notwithstanding the fact that the proteids of this seed give a strong 
Adamkiewicz reaction. When the seedlings were thirteen days 
old, however, they were found capable of autolysis with the formation 
of tryptophan. The results show that the seeds contain an ereptase 
and that after germination has proceeded for some time a tryptase 
also makes its appearance. 
Cucursira Prepo.—The seeds of the pumpkin give the same 
evidence of the presence of an ereptase as do those of the Hubbard 
squash. Two attempts were made to obtain preparations of this 
€nzyme. A quantity of ground seeds of the pumpkin were whipped 
up in water, and the shells, which floated on the surface, were skim- 
med off. After extracting for several hours, the mixture was strained 
through gauze and an attempt made to filter it clear. The fluid 
appeared to have a quantity of emulsified fat in it, and even the 
repeated filtration through pulp filters failed to make any impression 
on it. The mixture was allowed to stand two days with toluol 
to prevent bacterial action and was then readily filtered, yielding a 
perfectly clear filtrate, which however possessed no proteolytic 
Power. In the second attempt 452™ of ground seeds were extracted 
with sufficient water to make 275°° of milky looking extract which 
was found to have a marked action on Witte peptone. As soon 
as this extract was strained from the ground seeds it was mixed 
with an equal volume of saturated ammonium sulphate solution 
and allowed to stand over night. The precipitate was filtered off 
the next day, and when tested with Witte peptone was found to be 
very active, showing that the enzyme is either precipitated by half 
Saturation of its solution with ammonium sulphate, or else it sticks 
to the proteid precipitated by the salt. The precipitate was whipped 
up in water, transferred to a parchment paper bag, and dialyzed 
for two days in running water. When taken from the dialyzer and 
filtered clear, the solution was found to be inactive on Witte peptone. 
These results show that this enzyme is very sensitive and that some 
