336 PHYSIOLOGICAL CHEMISTRY 



brilliant investigators, our knowledge is progressing and broadening, 

 but we still lack that comprehensive understanding of the inner struc- 

 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 pro- 

 toplasm. 



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 

 proteids. 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. 1 Sturin also contains 13 per cent of histidin and 12 per 

 cent of lysin, while the other protamines appear to contain no dia- 

 mino-acids aside from arginin. Further, the protamines contain dia- 

 mido-valerianic acid, monoamido-valerianic acid, tyrosin or p-oxy- 

 phenyl-amidopropionic acid, skatolaminoacetic acid, a-pyrrolidin- 

 carbonic acid and serin. 2 Salmin 3 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. 4 In the histon from the nucleohiston 

 of the thymus, we find in addition to the hexone bases and the 

 monoamido-acids characteristic 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 



1 Kossel and his students. See Kossel and Dakin, Ueber Salmin und Clupein, 

 Zeitschrift fur physiologische Chemic, Band 41, p. 407. 



2 Kossel und Dakin, Beitrage zum System der einfachsten Eiweisskorper, Zeit- 

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



3 Abderhalden, Die Monoaminosauren des Salmins, Zeitschrift fnr physiologische 

 Chemie, Band 41, p. 55. 



4 See Kossel, Uber den gegenwartigen Stand der Eiweiss Chemie, Berichte der 

 Deutschen Chem. Gesellschaft, Jahrgang 34, p. 3214. 



