Studies on enzyme action.—Lipase

Abstract

It was first shown by J. Reynolds Green, in 1889, that germinating seeds of the caster-oil 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 caster-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 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, acts selectively on the mixture of ethereal salts derived from inactive mandelic acid, hydrolysing the dextro-constituent more rapidly than the lævo-constituent; but even in this case, inasmuch as the whole of the ethereal salt is hydrolysed eventually, the selective effort 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.