124 ^- ^- CANELLAKIS AND EDWARD HERBERT 



Discussion 



TisELius: May I ask did you get complete separation into S-RNA-a, -j3, -y ? 



Canellakis: Yes, we do get complete separation. 



TiSELius: Are the salt concentrations eluting the various components very 

 far apart ? 



Canellakis : I think they are of the order of o -05 m to o • 2 M. 



TiSELius: So you don't get much overlap between them ? 



Canellakis: They come out as distinct peaks 



Allfrey : I would like to ask if you have tried reconstituting this esterase- 

 treated RNA, not with the normal nucleoside triphosphates but with azaguanosine 

 phosphates or fluorouracil phosphates and see whether you still get functional 

 RNA? 



Canellakis: No, we have not tried that. 



Allfrey : It is interesting because the question is : does the specificity arise 

 in that end of the molecule or in the rest of it ? 



Canellakis : I agree that it is interesting. I think eventually we would like to 

 try this experiment. 



Davis : Do you have any indication of the extent to which the diesterase has 

 degraded the molecule, whether it has acted selectively at the ends or whether it has 

 also attacked the middle ? 



Canellakis : On prolonged incubation we can get some attack in the middle. 

 We think that it is probably due to some endonuclease action in our preparation but 

 for a half hour or so we seem only to be getting terminal degradation. 



Herbert : I should like to add that if you incubate for prolonged periods you 

 release 40 or 50^0 of the ribonucleotides as acid-soluble material. You can then no 

 longer reconstitute the amino acid-accepting capacity of our system. 



von der Decken : Do you obtain the pyrophosphate exchange when you use 

 S-RNA-amino acid complex instead of S-RNA ? 



Canellakis: I don't believe that our data permit us to answer that question. 



