PROTAMINES 91 



COMPOSITION OF YELLOW ELASTIC TISSUE: Ligamentum nuchce (BERG AND 



GIES). 



Water 57-57 P er cent. 



Solids 42 .43 per cent. 



Inorganic matter Q-47 



Organic matter 41 .96 



Fatty substance (ether-solu- 

 ble) 1. 12 



Coagulable protein 0.62 



Mucoid o . 53 



Elastin 31 .67 



Collagen 7 .23 



Extractives, etc o . 80 



Histones. The histories are proteins which stand in their chemical 

 structure between the true proteins and the protomines. On hydrolysis 

 they yield a large number of amino acids, among which the basic ones pre- 

 dominate. The basicity, however, is only slight. They are precipitated 

 by dilute ammonia and this precipitate is soluble in an excess of ammonia 

 in the absence of ammonium salts. They are precipitated by nitric acid, 

 the precipitate dissolving on heating and again appearing on cooling. They 

 give precipitates with solutions of other proteins. On heating, the histones 

 yield a coagulum which is easily soluble in very dilute acids. 



The histones are found in the nuclei of the red blood cells of birds, the 

 unripe testis in salmon and mackerel and in the ripe spermatozoon of the 

 sea-urchin. The thymus contains histone. The liver, kidneys, ox pan- 

 creas, and testis of mammals contain no histone-like substances. The 

 globin of the compound protein hemoglobin is to be regarded as a histone. 



Protamines. The protamines are basic proteins which are combined 

 with nucleic acid and form the chief constituent of the spermatozoa of the 

 salmon and other fish. They are relatively simple proteins yielding com- 

 paratively few amino acids on hydrolysis, among which the basic ones 

 predominate. From elementary analyses the following formula has been 

 suggested for the platinum salt of salmine. C 30 H 57 N 17 O 6 .4HC1.2PtCl 4 . 

 As seen from the formula, the protamines are extremely rich in nitrogen 

 which comprises from 25 to 32 per cent, of their weight. The protamines 

 dissolve in water and give a faintly alkaline reaction. They are precipitated 

 in acid solution by platinic chloride. The protamines, after the addition of 

 ammonia, precipitate true proteins, proteoses, and nucleic acid. On hy- 

 drolysis all protamines yield relatively large amounts of argenine and varying 

 amounts of histone, lysin, proline, alanine, valine, leucin, tyrosin, and ap- 

 parently also tryptophane. Protamines also do not contain sulphur or a 

 carbohydrate moiety. They are not changed by digestion with pepsin 

 hydrochloric acid. 



