ACTION OF TRYPSIN. 485 



still other bodies occur which will be considered later in connection with 

 the putrefactive processes in the intestine. 



The Action of Trypsin upon other Bodies. The neucleoproteins and 

 nudeins are so digested that the protein complex is separated from the 

 nucleic acid and then digested. The nucleic acids may, nevertheless, 

 be somewhat changed (ARAKI), which is probably brought about by 

 another enzyme, the nudease (SACHS). A cleavage of nucleic acids with 

 the setting free of phosphoric acid and purine bases is, according to IWA- 

 NOFF, 1 not brought about by trypsin. The splitting is first produced by 

 the action of nuclease or erepsin (see page 467). Gelatin is dissolved 

 and digested by pancreatic juice. A cleavage with the separation of 

 glycocoll and leucine does not occur (KUHXE and EWALD), or only to a 

 trivial extent (REICH-HERZBERGE 2 ) . 



The gelatin-forming substance of the connective tissues is not directly 

 dissolved by trypsin, but only after it has been treated with acids or 

 soaked in water at 70 C. By the action of trypsin on hyaline cartilage 

 the cells dissolve, leaving the nucleus. The matrix is softened and shows 

 an indistinctly constructed network of collagenous substance (KUHNE 

 and EWALD). The elastic substance, the structureless membranes, and the 

 membrane of the fat-cells, are also dissolved. Parenchymatous organs, 

 such as the liver and the muscles, are dissolved all but the nuclei, con- 

 nective tissue, fat-corpuscles, and the remainder of the nervous tissue. 

 If the muscles are boiled, then the connective tissue is also dissolved. 

 Mucin is dissolved and split by trypsin, while chitin and horn substance 

 do not seem to be acted upon by the enzyme. Oxyhcemoglobin is decom- 

 posed by trypsin with the splitting off of ha3matin. Trypsin has no 

 action upon fats and carbohydrates. 



The action of trypsin on simply constructed substances of known 

 constitution such as acid-amides, polypeptides, is of especially great 

 interest. In this regard we have the somewhat earlier investigations of 

 GULEWITSCH, GONNERMANN, and ScHWARZSCHiLD, 3 but the investigations 

 of FISCHER and of ABDERHALDEN and his co-workers, 4 are much more 

 complete and important. 



Beitrage, 1; Levene, Zeitschr. f. physiol. Chem., 37; Kutscher and Lohmann, ibid., 

 39; Kutscher and Otori, ibid., 43, and Centralbl. f. Physiol., 18. 



1 Iwanoff, Zeitschr. f. physiol. Chem., 39, which also contains the literature; Sachs, 

 ibid., 46. 



2 Kiihne and Ewald, Verh. d. naturh.-med. Vereins zu Heidelberg (N. F.), 1; Reich- 

 Herzberge, Zeitschr. f. physiol. Chem., 34. 



3 Hofmeister's Beitrage, 4, where the other works are also cited. 



4 Fischer and Bergell, Ber. d. d. chem. Gesellsch., 36 and 37; Fischer and Abder- 

 halden, Sitzungsber. der Kgl. Pr. Akad. d. Wissensch., Berlin, 1905. The works of 

 Abderhalden and co-workers cannot be specially cited, but may be found in Zeitschr. 

 f. physiol. Chem., 47, 48, 49, 51, 52, 53. 54, 55, and 57. 



