304 



H. G. BOMAN, I. A. BOMAN 

 TABLE II 



Amino Acid Incorporation into Acceptor RNA 



Incorporation of 



Type of RNA 



Specific activity of RNA 



c.p.m./o.u. 



per cent 



Arginine 



All amino acids 



Wild type (30S0) 

 Mutant (30S0A5) 

 Wild type (30S0) 

 Mutant (30S0A5) 



176 

 282 

 568 

 675 



100 

 160 

 100 

 119 



The concentration of the [^*C]-alga protein hydrolysate was 3-4 /xg./ml. ; 

 other conditions of the assay as described under Materials and Methods. The 

 specific activity in c.p.m./o.u. is given without correction for self adsorption and 

 geometry. 



10 20 30 



//g Arginine activating enzyme 



Fig. 4. Enzyme dependence for the formation of arginine-RNA. Purified 

 arginine-activating enzyme from strain 3oS(, (the wild type) was used with 24-0 

 optical units acceptor RNA from the same strain (open circles) and with 23 • 8 

 optical units acceptor RNA from the arg.R" mutant 3oS|,A5 (filled circles). The 

 blanks used in this experiment were the c.p.m. obtained by extrapolation to zero 

 jj-g. of enzyme. 



that the incorporation of the amino acid mixture is 19% higher into the 

 mutant RNA than into the wild type RNx\, whereas the incorporation of 

 arginine into the mutant RNA is 60*',, higher. However, it should be 

 pointed out, that in all experiments in Tables I and II, the incorporation 

 of the amino acid mixture is proportional to its concentration, while the 



