306 It. H. Chittenden — Ferments of Pineapple Juice. 



tinct separation. On the other hand, it is possible that the sub- 

 stance is a single body possessed of properties akin to both the above, 

 but this view seems hardly probable ; its precipitation by saturation 

 with magnesium sulphate and by sodium chloride possibly favor its 

 being a globulin, while its extreme solubility in dilute salt solutions, 

 in dilute acids and alkali are equally characteristic of both bodies. 

 The more or less constant solubility of the heat precipitates in 

 dilute alkalies favors its proteose nature, and if a proteose it is most 

 closely related to heteroproteose. The substances are, moreover, 

 alkaline reacting bodies completely precipitable by heat, especially 

 in the presence of a trace of acid. 



We are now occupied, with the aid of larger quantities of mate- 

 rial, in an attempt at a better separation of these bodies with the 

 hope of acquiring more definite knowledge regarding their chemical 

 nature, composition, etc. 



Whether globulin or proteose, these bodies present in pineapple 

 juice, are very resistant to the digestive action of the ferment. 

 Thus, long continued warming (3-5 hours) of fresh pineapple 

 juice with strong proteolytic power at 40° C does not, in the 

 least, change the temperature at which the several heat precipita- 

 tions occur ; a point which certainly indicates the resistance of these 

 proteids to j)roteolytic, or at least to this particular kind of proteo- 

 lytic, action ; the bodies in this respect resembling the atmid bodies 

 described by Neumeister.* 



Products formed by the 2>roteolijtic action of the ferment. 



On this point, we have made only a few preliminary experiments, 

 designed simply to throw some light on the nature of the ferment as 

 a proteolytic agent. The results indicate that the ferment is more 

 nearly related to trypsin than to pepsin, in that not only are proteoses 

 and peptone formed by its action, but also leucin and tyrosin. 



When washed and boiled blood fibrin, for example, is warmed at 

 40° C. with fresh pineapple juice of natural acidity for two or three 

 hours, the proteid matter is thoroughl}^ digested, but, as previously 

 stated, a fairly large residue of finely divided matter remains undis- 

 solved, resistant to the further action of the ferment. This anti- 

 albumid-like matter is readily soluble in weak solutions of sodium 

 carbonate, from which it is re-precipitated by addition of acetic acid, 



* Zeitschrift fiir Biologie, Band xxvi, p. 57. "Ueber die nachste Einwirkung ge- 

 spannter Wasserdampfe aiif Proteine und iiber eine Gruj^pe cigenthiimlicher Erweiss- 

 korper und Albumoseu." 



