349 



Studies on Enzyme Action. XIII. — Enzymes of the Emulsin Type. 

 By Henry E. Armstrong, F.E.S., and Edward Horton, B.Sc. 



(Received March 3— Read March 10, 1910.) 



[International Catalogue of Si'ientific Literature. 



Authors' title slip : — I). Q. 

 Subject slips : — 



D 1850 Phaseolunatiii — a /3-glucoside. Hydi'olysis by enzymes. 

 D 6300 Hydrogen cyanide. Estimation of 



D 8014 "I Enzymes of the emulsin type. Action on Fischer's glucoside, amygdaliu 

 Q 1240 J and phaseolunatin. 



D 8014 Cellase. Behaviour towards cyanophoric glucOsides of.] 



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., amygdalasf, a ^-glurase 

 and gluco-lactase : the first of these, amygdalase, being the enzyme by which 

 amygdalin is resolved into glucose and Fischer's glucoside, y8-glucase that by 

 which /3-glucosides are hydrolysed, gluco-lactase that which hydrolyses milk 

 sugar. 



Meanwhile the striking discovery has been made by Rosenthalerf 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 tliis hypothetical enzyme 

 may be spoken of as henznjaaasc. 



In continuing the study of the problem presented liy almond " emulsin," we 

 have been led to contrast it with active preparations producing somewhat 

 similar effects derived from other sources, our hope being that we should 

 sooner or later find one or other specific enzyme occurring alone. One of the 

 preparations which has attracted our special attention is that derived from 

 Phaseolns hmatus, the seed of which, as Dunstan and his co-workers have 

 shown, contains a cyanophoric glucoside that is resolved under the influence 

 of the enzyme present in the beans into glucose, acetone and hydrogen 



* Correction, paragraph 4, p. 325 : /()/• /3-methylglucoside read a-methylglucoside. 



t ' Biochemische Zeitschrift,' 1908, vol. 14, pp. 238—253; 1909, vol. 17, pp. 257—269. 



