84 



THE BIOSYNTHESIS OF PROTEINS 



of ribonucleoside diphosphates into polynucleotides the basic chemical 

 structure of which is identical to that of RNA (Grunberg-Manago et al., 

 1956; Ochoa, 1959). DNA does not seem to be required for this reaction, 

 but the enzyme also lacks specificity, and the nature of the polynucleotides 

 which are made under its action depends essentially on the composition of 

 the mixture of nucleoside diphosphates. It is only little influenced by the 

 nature of the primer. 



RNA COMPOSITION IN DIFFERENT BACTERIA 



Abbreviations: 



G = guanylic acid; A 

 U = uridylic acid; Pur. = 

 nucleotides. 



= adenylic acid; C = cytidylic acid; 

 purine nucleotides; Pyr. = pyrimidine 



Fig. 25. (Belozersky, 1959). 



No one knows whether the function of polynucleotidephosphorylase in 

 vivo is to make RNA or to destroy it. There are reasons to believe that the 

 synthesis of RNA follows another pathway, in which amino acids are some- 

 how involved. In Staphylococcus aureus and in Escherichia coli, amino acid 



