PAPAIN-PROTEOLYSIS. 161 



tinction which is now known to exist between the proteoses 

 and true peptones. Still later, however, Martin * studied the 

 action of papain on the several proteids occurring with the 

 enzyme in papaw juice, and found that the globulin present 

 there was converted by the enzyme into an albumose (/3- 

 phytalbumose), and that this substance was transformed into 

 a peptone-like body, which in turn was converted into leucin 

 and tyrosin. In this case the peptone-like body referred to 

 was presumably a true peptone hi the modern acceptance of 

 the term. Working with a somewhat different preparation 

 of papain, the writer f observed incidentally that in the diges- 

 tion of blood-fibrin and coagulated egg-albumin, deutero- 

 albumose and true peptone predominated among the soluble 

 products formed : t. e., peptone, non-precipitable by saturation 

 with ammonium sulphate. More recently Osswald J has also 

 reported that papain, as studied by him, gave rise to the 

 formation of peptone in neutral, alkaline, and acid fluids, but 

 that digestion was most complete and rapid in a hydrochloric 

 acid solution. With regard to the latter part of the statement, 

 we are inclined to believe that with most proteids the solvent 

 action of papain is greatest in the presence of sodium carbonate 

 and bicarbonate, although a mixture containing a very little 

 hydrochloric acid may be more active than a neutral solution 

 of the enzyme. Much depends, however, upon the presence 

 or absence of extraneous matters in the ferment-preparation 

 and on the amount of proteid present by which the presence 

 or absence of free acid is determined. This question, however, 

 is foreign to our present subject. 



If the solvent action of papain on proteids is really due to 

 conversion of the proteids into soluble albumoses and peptone, 

 then its action must be compared with that of a true digestive 

 enzyme and the process itself accepted as a genuine digestive 



* Martin, The Nature of Papain and its Action on Vegetable Proteid. 

 Journal of Physiology, 1885, vi. p. 337. 



t Chittenden, Papoid-digestion. Trans. Conn. Acad. Arts and Sciences, 

 1892, ix, p. 321. 



J Osswald, Untersuchungen iiber das Papain (Keuss). Munchener med. 

 Wochenschr., 1894, No. 34. 



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