Studies on enzyme action. XIII.—Enzymes of the type

In the previous communication of this series (No. XII, 1908, B, Vol. 80, pp. 321—329) the contention was advanced that “emulsin’’prepared from sweet almonds contains at least three distinct enzymes, viz.,amygdalase , aβ-glucase andgluco-lactase : the first of these, amygdalase, being the enzyme by which amygdalin is resolved into glucose and Fisclier’s glucoside,β -glucase that by whichβ -glucosides are hydrolysed, gluco-lactase that which hydrolyses milk sugar. Meanwhile the striking discovery has been made by Rosenthaler that emulsin has the property of inducing the formation of dextro-rotatory benzylidenecyanhydrol—such as may be obtained from amygdalin—from benzaldehyde and hydrogen cyanide; this raises the question whether there may not also be present in “emulsin” a specific enzyme capable of operating on the cyanophoric radicle of amygdalin and of resolving it into hydrogen cyanide and benzaldehyde. To avoid periphrasis this hypothetical enzyme may be spoken of as benzcyancise.