4 Mendel and Underhill — Papdin-digestion. 



In 1892, Chittenden' published the results of an extensive study of 

 the digestive action of "Papoid," a therapeutic agent prepared from 

 the various parts of the papaw plant, Carica papaya. The enzyme- 

 like character of the preparation was clearly shown by the readiness 

 with which it dissolved proteids like fresh and boiled fibrin, raw and 

 cooked beef proteids and coagulated egg-white in neutral, alkaline 

 and acid media, even in the presence of various antiseptic agents. 



While the attention of this investigator Avas directed particularly 

 to the conditions under which the proteolysis proceeds best, he inci- 

 dentally made several observations with reference to the products 

 formed. With coagulated egg-albumin, a peculiar albumose-like 

 body, a deuteroalbumose, a fairly large amount of peptone and some 

 leucin and tyrosin were isolated. With raw blood-fibrin and cooked 

 beef-proteids similar results were obtained.'^ Particularly conspic- 

 uous was a soluble albumose formed in the fibrin digestions. It Avas 

 complete!}' precipitable from a neutral solution by heat and partook 

 of the general character of hetereoralbumose, being insoluble in 

 water but completely insoluble in salt solutions as well as in dilute 

 acids and alkalies. This substance recalls the "globulin-like" body 

 described by Martin. While calling attention to the points of 

 resemblance between the action of papoid and trypsin, Chittenden 

 points out that the latter is ordinarily associated with an alkaline 

 secretion, and as a proteolytic agent acts to advantage only in alka- 

 line fluids. On the other hand, the action of papoid in neu- 

 tral solutions is increased by the addition of a very small amount 

 of h^'drochloric acid. Wurtz^ has also stated that the liquid juice of 

 the papaw is neutral in reaction. Chittenden therefore mereh^ con- 

 cludes "that the power possessed by papoid of dissolving various 

 forms of proteid matter is dependent upon an ordinarj^ digestive 

 action akin to, or identical with, that of digestive ferments in general, 

 whether animal or vegetable. 



In a subsequent paper from this laboratory' it was demonstrated 

 that not only are true albumoses (in Kuhne's sense) formed by vari- 

 ous commercial papain preparations acting in different media, but 



1 Chittenden : Transactions of the Connecticut Academy of Arts and Sciences, 

 1893, ix, p. 298. 



' We learn from Professor Chittenden that the quantities of leucin and tyrosin 

 found by him were small at the most. 



^Wnrtz and Bouchut: Comptes rendus de I'Academie des Sciences, 1879, 

 Ixxxix, p. 425. 



* Chittenden, Mendel and McDermott : American Journal of Physiology, 1898, 

 i, p. 255. The references to the literature are given in this paper. 



