HISTON AND ITS PREPARATION 



WALTER H. EDDY 



(Laboratory of Biological Chemistry of Columbia University, at the College of 

 Physicians and Surgeons, New York) 



Contents. — Introduction, 419; historical review of histon preparations, 420; 

 properties of histons, 425; thymus histon, 428; experimental, 430; summary of 

 conclusions, 438; selected bibliography, 439. 



I. INTRODUCTION 



Several years ago I began a study of some artificial protein Com- 

 pounds, as an introduction to an inquiry into the nature of protein 

 conditions in cells {y)} In preparing histon from calf thymus 

 glands by the Huiskamp (10), LiUenfeld (19) and Bang (2) 

 processes, I found that the ammonia-precipitated product from 

 neutral histon-hydrochlorid Solution was insoluble in water and 

 hence not available for the intended study of histon Compounds. 

 This result led me to reject the ammonia-precipitated histon and 

 to use, instead, a Solution of histon hydrochlorid (made neutral by 

 dialysis), Lately, in furtherance of this study, I have endeavored 

 to prepare water-soluble basic histon, free from admixture with 

 histon Salt of any kind. Various methods of preparation have been 

 proposed, but I find that thymus histon is almost invariably pre- 

 cipitated by the addition of an excess of ammonia to an acid Solu- 

 tion of the substance, in spite of the fact that solubility in water is 

 cited again and again as a property of histon. The only exceptions 

 to this Statement were found in Kos&el's original paper (12) on 

 goose-blood histon and in the description of Lota histon by Ehr- 

 ström (8). I have spent much time in determining by various 

 methods of preparation that the product precipitated by ammonia 

 (thymus histon) is invariably insoluble in water. Recently, in re- 

 viewing Fleroff's paper (9) on para-histon, I found a definite State- 

 ment that ammonia-precipitated thymus histon is insoluble in both 

 hot and cold water, and may be washed with water for purification. 



^ Figures in the text enclosed in parenthesis refer to the numbered iteras 

 in the bibliography at the end of this paper. 



419 



