Ryan — Note on the Action of Emukine on (d-Glf/comdcs. 55 



Owing to the sparing solubility of the acetyl derivatives of the 

 hexosides in water, the reactions were also tried in dilute alcohol 

 (80 CO. water + 20 c.c. absolute^ alcohol) ; but the glycosides remained 

 unaffected by eniulsinc. Undcn* tlu^ sanu^ conditions this enzyme 

 easily hydrolysed amygdaline. 



If we examine the above results, we shall see that the activity of 

 emulsine towards a glycoside depends not only on the configuration of 

 the molecule, as Emil Fischer has pointed out, but also on the nature 

 of the groups. Thus the replacement of four hydrogen atoms in 

 /S-/?-naphthyl-glucoside 



r— 0— n 

 OH j H OH I 



CH2OH— C — C— C— C — C • H 



H H OH H I 



II7C10-O 



by four acetyl radicals 



. OAc [ H^OaTI 

 CH2OAC— C— C— C— C— CH 

 H H OAc H I 

 H7C10 — 



converts a glycoside capable of hydrolysis by emulsine into one which 

 cannot be so hydrolysed. 



The conversion of the natural giucoside, salicine, into its benzoyl 

 derivative, populine, has a similar effect. 



Again, it is obvious that the emulsine test does not hold for all 

 ^-glycosides. It holds only for derivatives of fermentable sugars, 

 such as glucose, galactose, and maltose, and does not hold for 

 ^-glycosides of non-fermentable sugars, such as arabinose. 



