THE INDIVIDUAL GROUPS OF PROTEINS 467 



Nucleohistones of Lymphatic Organs. 



In a similar way to the preparation of thymus nucleohistone, nucleohistones 

 have been prepared from lymphatic glands, spleen and a lymphosarcoma. 



They differ from thymus nucleohistone in that their alkali salts and the 

 calcium chloride precipitate is soluble in i per cent, sodium chloride, but 

 otherwise closely resemble it. 



a-Nucleoprotein of the Pancreas. 



The minced glands are treated with -9 per cent, salt solution ; the filtered 

 solution is precipitated with acetic acid ; the precipitate is washed with dilute 

 acetic acid, dissolved in water containing a little sodium carbonate and pre- 

 cipitated with acetic acid. Solution and precipitation are repeated several 

 times. The precipitate is finally treated with alcohol and ether. These opera- 

 tions must be conducted at a low temperature. 



Pancreas a-nucleoprotein is an amorphous powder insoluble in water, 

 but soluble in dilute alkali ; it is insoluble in very dilute acetic acid, but slightly 

 soluble in more concentrated acid. It is decomposed by boiling with water ; 

 the filtered solution is precipitated by acetic acid and a precipitate is obtained, 

 containing less protein and more nucleic acid. 



/3-Nucleoprotein of the Pancreas. 



The minced glands are boiled with water and filtered. The solution is- 

 acidified with acetic or hydrochloric acid. The precipitate of /?-nucleoprotein. 

 is dissolved in dilute alkali and again thrown down with acid several times. 

 It is washed with alcohol and ether. 



The /3-nucleoprotein of the pancreas is an amorphous powder insoluble 

 in water and dilute acids, but soluble in dilute alkali. It is decomposed by 

 boiling with alkali, yielding guanylic acid (p. 301) and alkali metaprotein. 



a-Nucleoprotein of Blood Serum. 



Carbon dioxide is passed into horse's serum (p. 443) diluted with 20 

 volumes of water. The precipitate of nucleoprotein and globulin is allowed 

 to settle and separated by centrifuging. It is treated with i per cent, salt 

 solution for 6 hours and the solution which contains the globulin is poured 

 off. The sediment is dissolved in i per cent, salt solution containing a trace 

 of sodium carbonate and dilute acetic acid is added. The precipitate is filtered 

 off and washed with alcohol, ether and chloroform. 



It forms an amorphous powder insoluble in water and dilute acids, but is 

 soluble in excess of acetic acid ; it dissolves in dilute alkali. It loses its solu- 

 bility by contact with alcohol. It is precipitated by saturating its solution with, 

 magnesium sulphate or by half-saturation with ammonium sulphate. It is pre- 

 cipitated by calcium chloride, but is soluble in excess. 



Other a-Nucleoproteins. 



a-Nucleoproteins have been prepared from suprarenal glands, submaxillary 

 glands, placenta and muscle by slight modifications of the above process. The 

 gland is extracted with dilute alkali and precipitated with acetic acid and the 

 precipitate is purified by re-solution and re-precipitation. 



Other y3-Nucleoproteins. 



-Nucleoproteins have been prepared from the liver, mammary gland and 

 other organs in a similar way to the ^-nucleoprotein of the pancreas. 



