PROTAMINS 87 



while that of clupein sulphate is a multiple of 



C30H57N17O6, 2 H2SO4; 



but if an insufficient quantity of acid is present to completely 

 neutralize the protamin, "basic" salts, containing fewer equiva- 

 lents of acid, are readily formed. 



The sulphuric acid in these compounds is readily replaced by an 

 equivalent amount of hydrochloric (13), nitric, carbonic, or 

 chromic acids. The nitrates, chlorides and carbonates are readily 

 soluble, the sulphates sparingly soluble in cold, but more soluble 

 in hot, water, while the chromates are insoluble. The chloride of 

 salmin is soluble in methyl alcohol (13). 



The formula of sturin sulphate is, according to Kossel, a multiple, 

 either of 



2C33H61N17O7 + 5H2SO4 



or, more probably, of 



4C36H69N19O7 + IIH2SO4. 



Scombrin (derived from mackerel) sulphate possesses, according 

 to Kurajeff (21), the formula: 



C30H60N16O6, 2 H2SO4. 



It is soluble in water. The chromate is insoluble in water and 

 possesses the formula : 



C30H58N16O5, 2H2Cr04, 



differing, therefore, from the sulphate, not only in the acid com- 

 ponent, but also in the absence of one molecule of water for every 

 two molecules of combined acid. It is to be particularly noted 

 that the less soluble protein salt contains less water combined with the 

 protein. Remarkably analogous to this is the fact that whereas 

 salmin sulphate is freely diffusible through parchment paper (53), 

 clupein sulphate, which contains one molecule less of water for 

 every two molecules of combined acid, is almost indiffusible (49). 

 We shall have occasion to refer to analogous facts when considering 

 the mechanism of the coagulation of proteins (Chap. XII). 



The protamins also form compounds with chloroplatinic acid (28) ; 

 these compounds are insoluble in neutral water, alcohol or ether, 

 but are soluble in water containing an excess of acid. According 

 to Goto (13), the formula of the chloroplatinate of salmin is: 



C30H57N17O6, 4 HCl, 2 PtCl4. 



