ON THE CHEMICAL ASPECTS OF CYANOGENKSIS IX PLANTS. 151 



lysed by the enzyme gynocardase, present in the seeds, and by hot dilute 

 mineral acids, yielding one molecule each of prussic acid, dextrose and a 

 substance having the composition Ci;HsO,. The latter has not been 

 isolated, as it passes immediately into a brown, amorphous resin. Oi 

 alkaline hydrolysis gynocardin yields gynocardinic acid, which may, in 

 turn, be hydrolysed by dilute acids into dextrose and an acid of the foi'mula 

 CjH|(,0|;. The exact nature of gynocardin and its dooomposition products 

 remains to be determined. 



In addition to the glucosidos mentioned, which have been iiiolated 

 from the several pl.mts referred to, there can be little doubt that similar 

 substances exist in all the plants in which cyanogenesis occurs, and in a 

 few cases indications of tlie existence of such compounds have been 

 observed. 



In I'anginm edulo Treub suggests ' that the prussic acid may be 

 loosely combined with a sugar also found in the plant. Power and 

 Gornall - liave shown that a peculiarly unstable cyanogenetie substanct 

 exists in the seeds of Tarnklogenos Kv'r.U, and Easterlield and Aston 

 observed that the 'kanaka ' fruit {Corynocarpuslawigata) of New Zealand 

 yields prussic acid, probably produced by the action of an enzyme on the 

 glucoside kai^aUin, contained in the fruit.^ 



o 



Enzymes associatrd with Cvanogrnrtic Gutcosides. 



All these cyanogenetie glucosides are accompanied in the plants by 

 enzymes which decompose them, yielding products identical with those 

 olitainod by the action of hot dilute acids. 



There is as yet no method availal)le of chaiacterising enzymes, except 

 in a very general manner by the nature of their activities. The enzymes 

 present in these various plants cannot, therefore, be identified with 

 certainty, but it may be convenient to summ.arise what has l)een done 

 in the way of associating enzymes with the cyanogenetie glucosides they 

 have been found capable of decomposing. 



Emulsin Oj Sivcet or Bitter Almonds. 



This decomposes .amygdalin, mandelic nitrile glucoside, prulaurasin, 

 sambunigrin, anddhurrin, but does not hydrolyselotusin or phaseolunatin. 

 It has been pointed out by Fischer ' th.nt emulsin hydrolyses only tho.se 

 glucosides which contain /^dextrose residues. Hence the live first- 

 mentioned substances must be /i-glucosides. 



Lotfifie. 



This hydrolyses lotusin, the characteristic glucoside of Lot/us arabima, 

 and also decomposes amygdalin and salicin. On the contrary, the 

 emulsin of almonds has p?-actically no action on lotusin. Tt may therefore 

 be a.ssunied that lotase is not identical with the emulsin of almonds. 



ffynocardase. 



This decompo.ses gynocardin and amygdalin, and may be identical 

 with emulsin. 



' Am. Jard. But. BuU., 1896, vol. xiii. » Trani:. Chem. Soe., 1904, 85, 841. 



' Proc. Chen. Soc, 1903, 19, 191. ■• Zdt. Phyml. Che-m., 1899, 26, 60. 



