GENERAL CHEMICAL CHARACTERS OF PROTEINS 37 



characteristic constants of a protein; it indicates the quantity of 

 the cystine unit present in the molecule. 



In the following table the percentage of sulphur present in some 

 typical proteins is given : 



Sulnhur 



Observer. 



Goto (i). 

 Fleroff (2). 

 Bang (3). 

 Schulz (4). 

 Michel (5). 



Osborne and Campbell (6). 

 Osborne and Voorhees (7). 

 Hammarsten (8). 

 Osborne (9). 



Osborne and Voorhees (10). 

 Osborne and Campbell (n). 

 (12). 



Chittenden & Osborne (13). 

 Osborne and Voorhees (14). 



(15). 

 Hammarsten (16). 



(i7). 



Walter (18). 

 Levene (19). 

 Chittenden and Solley (20). 



Von Laar (21). 



Horbaczewski (22). 

 Mulder (23). 

 Schwarz (24). 

 Siegfried (25). 

 of pig's intestine 

 Aorta, Liver, 2-65-2-89 Lubarch (26). 



Spleen, etc. 

 Witte's peptone 1*22 Pick (27). 



2-97 



0-8 



ri-i-6 



Amyloid 



Hetero-prot.- 



albumose 

 Deutero-albu- 



mose (Thio) 

 Deutero-albu- 



mose (S. poor) 

 Other albumoses 



Phosphorus Content. 



Certain proteins, the phosphoproteins, are characterised by the 

 relatively large amount of phosphorus they contain. They must be 

 distinguished from the nucleo-proteins, in which the phosphorus is 

 contained in the prosthetic group, nucleic acid, and not in the protein 

 part of the molecule. The typical phosphoprotein caseinogen con- 

 tains, according to Hammarsten, 0*847 per cent, of phosphorus; 

 ovovitellin contains, according to Plimmer, i'i per cent.; ichthulin 

 from carps' eggs contains 0*43 per cent. (Walter, loc. cit.^ in the 

 table), and the corresponding substance from cods' eggs 0*92 per 

 cent (Levene). Plimmer and Scott have recently shown that the 

 phosphoproteins are easily decomposed by I per cent, caustic soda, and 

 are thus readily distinguished from the nucleo-proteins. Ordinary 

 proteins contain very small quantities, if indeed, any phosphorus. 



Halogen Content. 



Certain proteins contain very appreciable quantities of halogen. 

 The chief of these is the thyro-globulin of the thyroid gland, in which 



