1910.] 



Studies on Enzyme Action. 



367 



change was 13'5 per cent, in the case of Fischer's glucoside but only 3 per cent, 

 in that of amygdalin and 2 per cent, in that of the Phaseolus glucoside. 



It can scarcely be doubted that several specific enzymes exist which may 

 all be spoken of as ^-glucases. The common factor in these presumably is 

 a primarij memher sympathetic with the glucose member of the glucoside ; the 

 secondary member — in the case of the cyanophoric glucosides,the group CXY(CN) 

 — being different in the several enzymes. We are led to infer the existence of 

 such a primary member sympathetic with glucose in the case of almond-emulsin 

 and in that of the Phaseolus enzyme, as these are both controlled to a marked 

 extent by glucose, less action taking place if glucose be added in advance. 



On such an assumption, it is not difficult to understand the inactivity, for 

 example, of the Phaseolus enzyme towards amygdalin as compared with 

 Fischer's glucoside. It may be supposed that the molecule of glucose attached 

 to the Fischer's glucoside in amygdalin is so placed as to render association 

 between the hydrolyst and the primary member of the hydrolyte impossible 

 or nearly so, not only in the case of the Phaseolus enzyme but also 

 in that of almond-emulsin, action taking place in the case of the latter 

 only after the amygdalase, which accompanies the ;S-glucase, has prepared the 

 way by removing the terminal glucose group. — March 10, 191 O.J 



[The ' Comptes Kendus ' of March 21 (vol. 150, pp. 793—796) contains the 

 welcome announcement by J. Giaja that by means of an extract prepared 

 from the snail Helix pomatia, L., he has succeeded in separating from 

 amygdalin a non-reducing saccharose of the trehalose type. April 9.] 



[The cost of this investigation has been in large part met by a grant, for 

 which I am indebted to the Government Grant Fund of the Eoyal Society. — 

 H. E. A.] 



