SPECIAL PART 



CLASSIFICATION OF "ALBUMINS 

 (By COHNHEIM) 



A RATIONAL classification of albumins should start with the simplest 

 substances, the peptids and the peptones, and should then show how by 

 progressive combination of these simple substances there are built up 

 the albumoses and finally the albumins. This classification should 

 be based on a qualitative and quantitative synthesis of amino-acids. 

 Such a classification has indeed been attempted by Kossel, 1 who 

 considers the nucleus of the albumin -molecule to be represented 

 by the union of urea with a diamino-acid, as met with in arginin, 

 and that to this nucleus the other diamino-acids, mono-amino-acids, 

 etc., are linked on. According to this plan four distinct groups may 

 be distinguished : 



1. The protamins, which are rich in arginin. They differ from 



one another in the amounts of other bases and of mono-amino- 

 acids. 



2. The histones, which still possess a relatively high percentage 



of arginin and of other bases. 



3. Certain vegetable albumins very poor in arginin, and containing 



no lysin. 2 



i. All other albumins, containing all three hexone bases and the 

 greater number of amino-acids. This group cannot as yet be 

 subdivided any further. Compare p. 348. 



A second classification originating with Kiihne, 3 and worked out 



1 A. Kossel, Ber. d. deutsch. diem. Ges. 34. III. 3214 (1901) ; Bull, de la Soc. 

 chimique de Paris, 3rd Ser. T. 29, No. 14, 20th July 1903 ; Sitzungsber. d. Marburger 

 Ges. z. Bef. d. ges. Naturwiss. 1900, p. 21. 



- Kossel aud F. Kutscher, Zeitschr.f. physiol. Chem. 31. 165 (1900). 



3 W. Kiihne, Heidelberger Naturh.-medizin. Verein, N. F. 1. 236 (1876) ; Kiihue 

 and R. H. Chittenden, Zeitschr.f. Biol. 19. 159 (1883) ; 22. 423 (1885). 



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