Brill: Pangium edule and Hydnocarpus alcaUe 



41 



Auld ' has determined the rate of hydrolysis for amygdalin 

 by means of emulsin. Amygdalin reacts much more rapidly 

 with emulsin as well as with acids than does gynocardin. His 

 results with emulsin in the presence of added glucose and of 

 added hydrocyanic acid are in accord with the results obtained 

 by me for gynocardin, namely, the glucose inhibits the reaction, 

 the amount being dependent on the relative quantity of glucose 

 added, while hydrocyanic in smaller amounts accelerates the 

 action, but when added in larger quantities the inhibiting effect 

 is apparent. He has also found that the law of mass action 

 does not hold good in its entirety for enzymic action. A large 

 excess of the substrase does not cause a like increase in the rate 

 of reaction when this addition has proceeded beyond a certain 

 limit. The enzyme appears to be capable of reacting with only 

 a certain amount of the substrase in a stated interval of time, 

 and as long as the amount of this substrase exceeds a certain 

 limit, no acceleration of the reaction takes place on the addition 

 of more of the substrase. On the other hand, an increase in the 

 amount of the enzyme gives a corresponding acceleration of the 

 reaction, if the substrase is present in excess to react with the 

 original amount of enzyme present. In the preceding table 

 addition of more emulsin has accelerated the reaction. 



The juice from the crab contains a secretion which hydrolyzes 

 amygdalin giving hydrocyanic acid. To examine gynocardin in 

 this respect, a series of experiments was undertaken. The juice 

 of crabs, purchased in the local market, was obtained by ex- 

 pression, and comparative tests were made with it on amygdalin 

 and gynocardin. 



Table III. — Action of crab juice on 1 per cent solutions of gynocardin and 

 of amygdalin. 



Time. 



Glucoside. 



Gluco- 

 side. 



Crab 

 juice. 



Gluco- 

 side 

 hydro- 

 lyzed. 



Hours. 

 24 



24 

 28 



: 



n 





cc. 

 25 

 25 

 25 

 25 

 25 

 25 



10 

 10 

 10 

 10 

 10 

 10 



Per cent. 

 51.99 

 11.60 

 69.10 

 13.16 

 75.67 

 17.18 















According to Table III gynocardin is likewise attacked more 

 slowly by crab juice than is amygdalin. Toluene was added in 



7 Auld., S. J. Manson, Journ. Chem. Soc. London (1908), 93, 1251. 



