350 



Studies on Enzyme Action. IX. — The Enzymes of Yeast : 



Amygdalase. 



By E. J. Caldwell, B.Sc. (Lond.), Leathersellers' Company's Besearch 

 Fellow, Chemical Department, City and Guilds of London Institute, and 

 S. L. Courtauld, B.A. 



(Communicated by Professor Armstrong, F.E.S. Eeceived May 9, — 

 Eead May 23, 1907.) 



[International Catalogue of Scientific Literature. 



Author's title slip : — D. Q. R. 

 Subject slips : — 



D 1850 Amygdalin, hydrolysis of, by amygdalase. 



> Amygdalase, a new enzyme in yeast. 

 R 1910 Yeast, new enzyme in (amygdalase).] 



The number of the ' Gazzetta Chimica Italiana ' published on February 12, 

 1907, contains a communication received by the editor on December 17, 1906, 

 " Su le azioni idrolitiche diverse prodotto da un solo enzima," by L. Marino 

 and G. Sericano,* in which the conclusion is arrived at that the resolution of 

 amygdalin by an extract of yeast into glucose and amygdonitrileglucoside 

 is conditioned not by the enzyme maltase but by invertase. 



We have long been aware that maltase does not effect the hydrolysis of 

 amygdalin and to this extent can confirm Marino and Sericano's observations ; 

 but the conclusion that the cyanophoric glucoside is hydrolysed by invertase 

 is not in accordance with our observations, which show that a specific enzyme, 

 not hitherto recognised as a constituent of yeast, is the active agent in 

 separating the glucose : it will be convenient to speak of this enzyme 

 as amygdalase. 



Amygdalin is one of the few natural glucosides which give two molecules 

 of glucose when hydrolysed, the other product being benzylidene cyanhydrol, 

 which — in dilute solution — decomposes spontaneously into benzaldehyde and 

 hydrogen cyanide. There is reason to suppose that the two molecules of 

 glucose are attached to one another — that is to say, that amygdalin is derived 

 from a biose.f 



It was shown by Emil Fischer, in 1894,t that an extract of dried Frohberg 



* Vol. 37, pp.45— 51. 



t Evidence has already been adduced in favour of the view that this biose is not 

 maltose (Caldwell and Courtauld, ' Trans. Chem. Soc.,' 1907, vol. 91, p. 670). 

 J < Deut. chem. Ges. Ber.', 1894, vol 27, p. 2989. 



