HYDROLYSIS — ESTIMATION OF BASES IN PNA 



205 



Table II 

 Purine and Pyrimidine Components of Yeast Ribonucleic Acid Found by 



Various Investigators 



" The original publications .should be consulted for complete descriptions of the samples, the methods of 

 purification, and the methods of hydrolysis used. The cytidine values after acid hydrolysis, witli the excep- 

 tion of those of reference 8 have not been corrected for deamination. Commercial N. A. = commercial ribo- 

 nucleic acid. The preparation numbers given are the same as those of the original publication (Chargaff et 

 al.«). 



nucleotides. A comparison of the various samples analyzed by different in- 

 vestigators reveals differences which appear to be significant. The results 

 indicate that considerable variation occurs in the composition of samples 

 of yeast ribonucleic acid, depending on the procedure employed during 

 their preparation and purification.^" Because of such variation it appears 

 that a better characterization of a particular ribonucleic acid lies in the 

 direct analysis of the purified nucleoprotein or of the particulate component 

 containing the nucleic acid. 



5. Application to Purified Nucleoproteins, Particul.\te Components 

 OF Cells, and Tissues 



The analysis of the ribonucleic acid occurring in a purified nucleoprotein, 

 in a separated particulate component of cells like mitochondria or micro- 



^° For differences in yeast RNA composition depending on the conditions under 

 which yeast is grown see K. Dimroth and L. Jaenicke, Z. Naturforsch. 56, 185 

 (1950). 



