PAPAIN-PROTEOLYSIS, WITH SOME OBSERVA- 

 TIONS ON THE PHYSIOLOGICAL ACTION 

 OF THE PRODUCTS FORMED.* 



BT R. H. CHITTENDEN, LAFAYETTE B. MENDEL, AND 

 H. E. McDERMOTT. 



WHEN papain, the proteolytic enzyme of the papaw plant, 

 was first subjected to careful study by Wurtz and Bouchut,f 

 it was compared in its mode of action to trypsin, not alone 

 because it was active in a neutral medium, but especially 

 because of the character of the resultant products. Thus, it 

 was stated that by the vigorous action of papain upon blood- 

 fibrin, complete peptonization resulted, with the formation of 

 some leucin in addition. Naturally, at this time (1879) there 

 was no differentiation of proteoses and peptones ; hence all 

 that the above statement implied was a conversion of the 

 proteid into a soluble form, precipitable by alcohol and not 

 coagulated by heat nor by acids, although the presence of 

 leucin would certainly suggest the formation of true peptone. 

 Later, Martin J pointed out that the enzyme acts vigorously 

 in the presence of sodium carbonate (0.25 per cent) and that 

 as products of digestion there are formed in both neutral and 

 alkaline solutions an intermediate globulin-like body, peptone, 

 leucin, and tyrosin, the last two being formed in small quan- 

 tity. Here, likewise, the word peptone must be interpreted 

 as meaning simply soluble proteid, and not carrying the dis- 



* Reprinted from the American Journal of Physiology, vol. i. An abstract 

 of this paper was presented at a meeting of the American Physiological 

 Society held at Washington, May 4, 1897. See Science, N. S., v, June 11, 1897, 

 p. 902. 



t Wurtz and Bouchut, Sur le ferment digestif du Carica papaya. Comptes 

 rendus, 1879, Ixxxix, p. 426. Wurtz, Sur la papaine- Contribution a 1'histoire 

 des ferments solubles. Ibid., 1880, xc, p. 1379 ; and xci, p. 787. 



t Martin, S. H. C., Papain-digestion. Journal of Physiology, 1884, r, 

 p. 213. 



