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The Configurational Properties of 



Ribonucleic Acid Isolated from 

 Microsomal Particles of Calf Liver 



BENJAMIN D. HALL PAUL DOTY 



Department of Chemistry, Harvard University 



Although ribonucleic acids (RNA) from many sources have been examined 

 by physical methods within the last few years no clear and consistent picture 

 of the configurational properties of RNA has materialized. Most studies of 

 RNA have been complicated by spontaneous changes of molecular weight, ag- 

 gregation under some conditions and degradation under others. In the work 

 reported here we have avoided these complications by finding experimental con- 

 ditions under which the RNA is stable and have then proceeded to establish 

 its configurational properties in solution by means of several different physical 

 methods. 



The choice of microsomal particles from liver as our source of RNA was 

 prompted by the particular importance that these ribonucleoprotein particles 

 have assumed by virtue of their participation in protein synthesis [1, 2] and the 

 fact that they can be isolated in pure form [3] before the preparation of the 

 RNA itself. 



It is important to emphasize at the outset that our major emphasis in the 

 work reported here has been on the configurational properties of stable RNA 

 isolated from these particles. We defer until a later time a report on the molecu- 

 lar weight and configuration of RNA within the microsomal particles and the 

 relation of the work presented here to these properties. 



THE PREPARATION OF RNA 



Preparation of Microsomal Particles. The procedure summarized below 

 evolved from those used by Zamecnik et al. [1] and by Petermann and Hamil- 

 ton [4] for the isolation of similar particles from rat liver. Calf liver was 



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