RECENT WORK 

 ON PROTEIN-HYDROLYSIS 



By J. REYNOLDS GREEN, Sc.D.,F.R.S. 

 Professor of Botany to the Pharmaceutical Society of Great Britain 



The decomposition of proteids under the influence of the 

 various enz3^mes which attack them has been for many years 

 the object of much research. The early workers obtained from 

 such digestions a great number of bodies whose relationships 

 were very inadequately interpreted, and whose identities were 

 the subject of much disputation. It was not till the time of 

 Kiihne that any course of decomposition was suggested that 

 appeared to possess any great probability. 



Kilhne's hypothesis was known as the " cleavage " theory 

 of proteolysis, from the fact that he supposed that the proteid 

 attacked — a globulin or an albumin — was at once separated into 

 two approximately equal varieties, which were possessed of 

 distinctly different properties. One of these he termed hemi- 

 albumose, the other anti-albnmose. The subsequent decompositions 

 of these two albumoses he held to go on side by side, but 

 independently, so that among the products of digestion two 

 distinct groups of substances appeared, a hemi- and an anti-group. 

 The pepsin of the stomach converted the two albumoses into 

 hemi-peptone and anti-peptone respectively, and the two peptones, 

 existing in the same mixture, and not being readily capable 

 of separation, formed cimphopcptone. The action of the trypsin 

 of the pancreas converted the hemi-peptone into a number of 

 crystalline bodies, chiefly consisting of amino-acids, such as 

 leucin and tyrosin, with a certain number of amido-bodies such 

 as asparagin. 



This view of Kiihne's, though evidently only provisional, 

 was accepted by physiologists for many years, and the various 

 discoveries which were made by different workers in both 

 animal and vegetable physiology were fitted into it with, 

 however, gradually increasing difficulty. 



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