196 CHEMISTRY OF THE PROTEIDS CHAP. 



As intermediary products of tryptic digestion, albumoses, 1 and in 

 particular deutero-albumoses, are also formed. 2 According to Umber, 3 

 in many cases these deutero-albumoses have been mistaken for nucleic 

 aeids. 



By subjecting egg-albumin and casein to the combined action of 

 pancreatic and splenic extracts, or to the combined pulp of the organs, 

 Levene and Stoky 4 found digestion to proceed much quicker than 

 corresponded to the sum of the action of the two organs. They 

 believe the spleen to facilitate the conversion of trypsinogen into 

 trypsin, as the spleen does not augment the digesting power of the 

 pancreas after the trypsinogen has become converted into trypsin. 



In this connection may be mentioned the interesting results which 

 Vernon 5 has obtained by studying the protective value of proteids 

 and their decomposition-products on trypsin : " Most proteids have 

 practically the same protective value, about 45 per cent of the trypsin 

 of an extract being destroyed per hour in presence of 0'4 per cent of 

 proteid; 27 per cent in presence of 1 per cent; 12 per cent in 

 presence of 2 per cent ; 7 per cent in presence of 4 per cent of 

 proteid. When no proteid was present 56 per cent of the ferment 

 was destroyed. Hydrated proteids have a slightly greater protective 

 value than native proteids, and the decomposition-products of proteid 

 hydrolysis a slightly greater one still. ... If the acid-radicals in the 

 various substances be previously neutralised by the addition of an alkali 

 they entirely lose their protective power over the ferment." As the 

 difference in the protective value between the native proteids and their 

 hydrolysed derivatives is but slight, ' it would seem as if most of the 

 COOH-groupings which are present in the products of proteid-decom- 

 position are likewise present as such when forming part of the com- 

 plex proteid-molecule, and in either condition are capable of combining 

 with any molecules of alkali brought in their neighbourhood. This 

 conclusion is at variance with that of Hofmeister, 6 who considers that 

 the amido-acid 'nuclei in the proteid-molecule are linked together by 

 an NH 2 -grouping of one nucleus uniting with a COOH -grouping of 

 another to form a 



> CHNH CO-grouping. 



1 R. Nemijeister, Zeitschr. f. BioL 23. 381 (1887), 24. 267 (1887) ; U. Biffi, 

 Virchaw'g Arch.*l62. 130 (1898). 



2 R. Neumeister, Zeitschr. f. BioL 23. 381 (1887), 24. 267 (1887). 



3 F. Umber, Zeitschr. f. klin. Mediz. 43. Nos. 3 and 4 (1901). 



4 P. A. Levene and L. B. Stoky, Amer. Journ. of Physiol. 12. 1, (1904). 



5 H. M. Vernon, Journ. of Physiol. 31. 346 (1904). 



6 Hofmeister, Ergebnisse d. Physiol. 1. 787 (1902). 



