PROBLEMS OF PHYSIOLOGICAL CHEMISTRY. 151 



ture of the molecule that would serve to illuminate our field of vision 

 and give us a clear conception of the chemical constitution of this group 

 of physiologically important ground substances in living protoplasm. 



As is well known, the proteid bodies constitute a group of widely 

 divergent substances. Of these, the basic protamines are undoubtedly 

 the simplest and lowest in the scale, and it is quite probable, as sug- 

 gested by Kossel, that these substances constitute the nuclei of all pro- 

 teids. The protamines differ somewhat among themselves, but as a 

 group they are characterized by their high content of diamino-acids, 

 especially arginin. Thus, salmin yields on decomposition 84 per cent, 

 of arginin, clupein 82 per cent., cyclopterin 62 per cent., and sturin 58 

 per cent.* Sturin also contains 13 per cent, of histidin and 12 per 

 cent, of lvsin, while the other protamines appear to contain no diamino- 

 acids aside from arginin. Further, the protamines contain cliamido- 

 valerianic acid, monoamido-valerianic acid, tyrosin or p-oxyphenyl- 

 amidopropionic acid, skatolaminoacetic acid, a-pyrrolidincarbonic acid 

 and serin, f Salmin J has also been shown to contain alanin, leucin, 

 probably also phenylalanin and aspartic acid. 



If we pass from the simplest of the proteid bodies to the most 

 complex, as the nucleins, we find present in the latter not only arginin, 

 lysin and histidin, but, in addition, such bodies as thymin, the purin 

 bases, leucin, aspartic and glutamic acids, two sulphur-containing 

 groups, furfurol-forming groups, pyrrolidincarbonic acid, a skatol- 

 forming group, phosphoric acid, amidovalerianic acid, a levulinic acid- 

 forming group, glycosamine, pentose, uracil and probably phenylamido- 

 propionic acid.§ In the histon from the nucleohiston of the thymus, 

 we find in addition to the hexone bases and the monoamido-acids charac- 

 teristic of the ordinary albuminous bodies such substances as glycocoll, 

 cystin and alanin. 



These statements, brief and incomplete though they are, will serve 

 to illustrate the complexity of the proteid molecule, and at the same 

 time they indicate the close genetic relationship which unquestionably 

 exists between the varied members of this large group of substances. 

 There is no doubt that Kossel and his co-workers in their efforts to un- 

 ravel the constitution of the protamines are pursuing a wise course in 

 paving the way for a comprehension of the exact nature of the more 

 complicated proteids. There is no doubt that the protamines of one 



* Kossel and his students. See Kossel and Dakin, ' Ueber Salmin und 

 Clupein,' Zeitschrift fur physiologische Chemie, Band 41, p. 407. 



t Kossel und Dakin, ' Beitrage zum System der einfachsten Eiweisskorper,* 

 Zeitschrift fur physiologische Chemie, Band 40, p. 565. 



X Abderhalden, ' Die Monoaminosauren des Salmins/ Zeitschrift fur 

 physiologische Chemie, Band 41, p. 55. 



? See Kossel, ' Ueber den gegenwiirtigen Stand der Eiweiss Chemie,' 

 Berichte der Deutschen Chem. Gesellschcift, Jahrgang 34, p. 3214. 



