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CHEMISTRY: K. G. FALK 
In the case of the lipase material it was shown that a definite quantity 
of the enzyme can react with only a definite quantity of glyceryl triace- 
tate in a given time. When the enzyme and ester are present in this 
ratio an increase in the amount either of ester or of lipase material does 
not increase the extent of the action. 
Preparation, Composition, and Activity of the Solid Lipase-Materials. 
Solid esterase preparations, active as a rule, were obtained by precipi- 
tating the filtered and dialyzed aqueous extracts with acetone. The 
dialyzed salt-extracts, which contained the lipase material in suspension, 
give an inactive preparation after filtration, washing of the precipitate, 
suspension of it in acetone, and standing in this solvent. On the other 
hand, on standing in water for about two weeks, the soluble esterase- 
preparation lost its activity, while the insoluble lipase-preparation re- 
tained its activity unchanged. 
The nitrogen-content of different preparations of esterase, referred to 
the ash-free and moisture-free substance, ranged from 15.4 to 16.3%, 
and the phosphorous-content ranged from 0.36 to 0.90%. The ash from 
these preparations amounted to 5%. Tests made upon them showed 
the presence of no carbohydrate, of much tryptophane, of much aro- 
matic-group compounds, and of a trace of tyrosine. The soHd prepara- 
tions from the lipase material showed a more constant composition, giving 
an average nitrogen-content of l-6.8%, referred to the ash-free and mois- 
ture-free substance, and an average phosphorus-content of 0.68%. The 
ash was 4.3%. The preparations gave a negative test for carbohydrates, 
a faintly positive one for tyrosine, a distinctly positive one for trypto- 
phane, and a strongly positive one for aromatic groups. The forms of 
combination of the nitrogen in the different preparations were found to 
be the same as those recorded in the Hterature for typical proteins from 
various sources, with minor differences in the relative amounts of the 
various amino acids present. About 25% of the nitrogen was present 
in the form of arginine, a characteristic of seed proteins. Similar results 
were found with the soy-bean preparations. 
These analyses, taken in connection with the method of preparation 
which removed all fatty (ether-soluble) substances, show that both es- 
terase and lipase preparations are essentially protein in character. The 
esterase preparation may be considered to be an albumin, the lipase 
preparation to be a globuKn. 
The inactivation of these preparations by water, by salt solutions, or 
by acetone may be compared with the inactivation of the original castor 
and soy-bean preparations by heat. The loss in weight of these prepa- 
