1912.] 



Studies on Enzyme Action. 



375 



allowed to ripen upon the plant — the nature is said to be drained out of it ; 

 the tops carrying the seed are therefore cut off and allowed to ripen 

 separately by exposure to the sun on rough drying frames. The seed is 

 often afterwards put into a heated chamber to advance the ripening and 

 drying, so that it may be put upon the market. 



The accumulation of linamarin in the seed takes place at a comparatively 

 late stage, though the glucoside disappears eventually. The very young seed 

 pod affords only a faint indication of hydrogen cyanide ; the largest amount 

 is obtained when the seed assumes a full green colour. There is a coincident 

 increase in the proportion of enzyme, as shown by the following results 

 obtained by digesting 1 grm. of the entire seed capsule with a solution of 

 linamarin : — 





Tery small. 



Medium size, j Fully grown. 





[ 0-8 



1 -25 9 75 



The Enzymic Activity of the Linacece. 



We have applied the method developed in the two previous communica- 

 tions to the study of the enzymes present in the leaf and seed of various 

 species of Linacese, and have dealt with more than 60 reputed species. 



It is a striking fact that apparently, in this genus as in that of lotus, 

 enzymic activity is correlated with the presence of a cyanophoric glucoside ; 

 the yellow-flowered species, which are free from cyanide, show little if any 

 enzymic activity towards Linamarin, amygdalin, prunasin and salicin. The 

 fact is, perhaps, not without significance that these species are all slow in 

 germinating and slow in growth. 



Some of the results obtained with the various species, showing the enzymic 

 activity of leaf and seed, are recorded in Tables I and II ; the values given in 

 Table II are calculated from those given in Table I, supposing the degree 

 of activity towards Linamarin to be the same in all cases. 



The results obviously require interpretation from various points of view. 

 It is clear, in the first place, that a variety of enzymes are present in the 

 leaf and seed of the various species and that the proportions in which they 

 are present are subject to considerable variation. 



The activity towards linamarin may safely be attributed to linase and 

 linase alone. L. cathartieum is the only one of the species examined which 

 has a low degree of enzymic activity and almost no action on linamarin : 

 this species also -affords but a small proportion of hydrogen cyanide. 



