Yesterday Dr. Heppel told me about his telephone conversation with you concerning polynucleotide phosphorylase. At this moment
our supply is rather limited but we are working up a mammoth preparation and unless things go even more awry than they have
up to now we'll have a good supply soon. In any case, we'll send you some of what we now have. Although it has gone
through many steps, the specific activity is rather low. Nevertheless it is good enough to show a lag for polymerization.
The source was A. agile. Its designation is 5-27AR58, 10.5 mg. protein per ml, specific activity (exchange assay) is 21. It
may be more helpful to tell you that .005/20 ml. phosphorolyzed 50 per cent of 0.05 mg. poly A in 1 hour at 37 degrees (pH
8.2, 0.01 M MgH).
Dr. Heppel told you that I have been carrying out some experiments concerning the action of polynucleotide phosphorylase on
acceptor RNA. Giulio Cantoni and Marianne Manago did a few preliminary experiments last spring and Giulio and I are now continuing
them. I told Fred Bergmann about these last week.
Fred has sent me the procedure for E. coli acceptor RNA and I should also thank you for your offer to send me some of that
We will send the polynucleotide phosphorylase either later this week or early next week. We'll pack it in dry ice and
send it air mail - special delivery, and we'll send a telegram so you will know when to expect it. Please write if there
is any further information about the enzyme you'd like to have.