EREPSIN, 493 



HEKMA, FALLOISE, and others, which, however, DELEZENNE says, 1 is 

 formed in the leucocytes and PETER'S glands. 



Erepsin. This enzyme, discovered by O. COHNHEIM, has no direct 

 action upon native proteins with the exception of casein, but has the 

 power of splitting proteoses, peptones and certain polypeptides. In 

 this change mono- as well as diamino-acids are produced. Erepsin 

 occurs in the mucous membrane and in the intestinal juice of man as 

 well as of dogs; the mucous membrane seems to be richer than the juice 

 (SALASKIN, KUTSCHER and SEEMANN 2 ). An enzyme like erepsin also 

 occurs in the pancreas (BAYLISS and STARLING, VERNON), and this has 

 the power of acting upon casein, but not, or only faintly, upon fresh 

 fibrin. This erepsin is probably identical with the enzyme nitdease, 

 discovered by F. SACHS in the pancreas, which acts upon nucleic acids, 

 while NAKAYAMA claims that erepsin differs from trypsin in having a 

 cleavage action upon nucleic acids. Intestinal erepsin is not inhibited, 

 according to GLAESSNER and STAUBER, by blood-serum and differs in 

 this regard from trypsin. Erepsin shows a great similarity to the intra- 

 cellular enzymes active in autolysis, and according to VERNON and others 

 erepsins occur in the various tissues of invertebrates as well as verte- 

 brates. These tissue erepsins, which are closely related to the auto- 

 lytic enzymes, if they are not identical with them, behave somewhat 

 differently from the intestinal erepsin and are not identical therewith. 

 Enzymes, having an action similar to erepsin, occur, VINES believes, 3 

 in all plants so far investigated. 



Erepsin becomes inactive on heating to 59. It works best in 

 alkaline solution, but has hardly any action in faint acid reaction. In 

 this regard, as well as by the fact that only a little ammonia is split off 

 by its action upon peptone substances, it differentiates itself from cer- 

 tain of the autolytic enzymes studied so far. The optimum of alkalinity 

 is, according to EuLER, 4 at least in the splitting of a polypeptide, much 

 lower than the optimum for tryptic digestion. 



The secretion of the GLANDS IN THE LARGE INTESTINE seems to con- 

 sist chiefly of mucus. Fistulas have also been introduced into these 



1 Boldyreff, Arch. d. scienc. biolog, de St. Petersbourg, 11; Bayliss and Starling, 

 Journ. of Physiol., 29, 30; Hekma, 1. c.; Falloise, see Biochem. Centralbl., 4, p. 153; 

 Vernon, Journ. of Physiol., 33; Delezenne, Compt. rend. soc. biolog., 54 and 56. 



2 Cohnheim, Zeitschr. f. Physiol. Chem., 33, 35, 36, and 47; Salaskin, ibid., 35; 

 Kutscher and Seemann, ibid., 35. 



3 Bayliss and Starling, Journ. of Physiol., 30; Vernon, ibid., 30 and 33. See also 

 Cohnheim and Pletnew, Zeitschr. f. physiol. Chem. 69; F. Sachs, Zeitschr. f. physiol. 

 Chem., 46; Nakayama, ibid., 41; Glaessner and Stauber, Bioch. Zeitschr. 25; Vines, 

 Annals of Botany, 18, 19, and 23. 



4 Zeitschr. f. physiol. Chem., 51, 



