606 
Studies on Enzyme Action.—Lrpase. 
By Henry E. ARMSTRONG, F.R.S. 
(Received July 29, 1905.) 
[International Catalogue of Scientific Literature. 
Author’s title slip :—D. Q. 
Subject slips :— 
D 8014 Q 1240 Ricinus Lipase. ] 
It was first shown by J. Reynolds Green, in 1889, that germinating seeds 
of the castor-cil plant contain an enzyme which is capable of hydrolysing 
castor oil. Of late years an industry has been based on this discovery, as it 
has been found that if ground ungerminated castor-oil seed be mixed with 
an ordinary fatty oil and a small quantity of acid (preferably acetic), the fatty 
matter is almost entirely hydrolysed into glycerol and fatty acid: as the 
change takes place rapidly, at a little above an ordinary temperature, the 
hydrolysis of fats may be effected in this manner with considerable advantage 
on economic as well as other grounds.* 
The study of vegetable lipase is of special importance, as the ordinary fats 
—which are hydrolysed under its influence with peculiar readiness—are not 
asymmetric material but simply glycerides of acids of the acetic or oleic 
series. The discovery of the nature of the process is, therefore, of particular 
interest, in order that a comparison may be instituted between this enzyme 
and those which are known to act selectively. The interest of the inquiry 
is enhanced by the fact that animal lipase, according to Dakin,t acts 
selectively on the mixture of ethereal salts derived from inactive mandelic 
acid, hydrolysing the dextro-constituent more rapidly than the levo- 
constituent; but even in this case, inasmuch as the whole of the ethereal salt 
is hydrolysed eventually, the selective effect of lipase is of a different order 
from that displayed, for example, by an enzyme of the sucroclastic class, 
which can only attack one member of a pair of enantiomorphous isomerides. 
Among the chief points of interest already established by Connstein and 
his fellow workers are, firstly, that Ricinus lipase is effective only in presence 
of acid; secondly, that it acts preferentially on the natural fats; other 
ethereal salts are scarcely if at all attacked by it.t 
* ‘Comp. Connstein : V. Internationaler Congress fiir Angewandte Chemie,’ Berlin, June, 
1903, vol. 2, p. 537. 
t ‘Journal of Physiology,’ 1903, vol. 30, p. 253; 1905, vol. 32, p. 199. 
t The literature of the subject is summarised in an article by Connstein, “ Ueber 
fermentative Fettspaltung,” in Asher and Spiro’s ‘Ergebnisse der Physiologie, 
Biochemie,’ 1904, vol. 3, p. 194. 
