Original Repository: Stanford University Libraries. Department of Special Collections and University Archives. Arthur Kornberg Papers
Reproduced with permission of H. Gobind Khorana.
Medical Subject Headings (MeSH):
The Synthesis of DNA, 1953-1959
Letter from Arthur Kornberg to H. Gobind Khorana (February 28, 1957)
Letter from Arthur Kornberg to H. Gobind Khorana (March 8, 1957)
Box Number: 24
Folder Number: 24
March 18, 57
I am happy to say that the PRPP problem is now being concluded satisfactorily.
Problem 1--The isolation of PRPP in a relatively pure state is accomplished by isolation of di salt at pH 7.5-8 at controlled
temperature. Graph I shows ion exchange analysis of 2[mu] moles of PRPP, prepared from middle labelled ATP. As you see a
little degradation (in the desired direction) had already occurred during isolation.
Next, we hydrolysed (degraded) same amount of PRPP (same sample) and put it on the same column (regenerated) and used identical
elements and elutions. We obtained Graph II. Details are on the Graph, since about40 counts are due to background, practically
all counts appeared in RiboseDiP[?] fraction and coincided with the ribose peak.
The specific and quantitative degradation of PRPP to RiboseDiphosphate plus Pi caused a lot of anxiety but the solution was
found in using Ba ion catalysis at room temperature at pH 10.5.
Thank you so much for the plentiful sample of "hot" ATP--terminal labelled. I made
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PRPP from it the same day and have in fact been using it in recent experiments since I could afford to be liberal with that
sample. It was the middle labelled ATP that had gone down really low by now but I am glad that the very last experiment (Graph
II) worked. Although the counts are not very high, the picture proves the point quite clearly.
In a day or so I will forward the results of PRPP from terminal labelled ATP. It does go as expected and about 90% of the
counts appear in the Pi--but the pictures are not very pretty yet, because of the PRPP sample having POP and RSP contaminations
we just want to repeat isolation of PRPP in at least as good a state as the sample in Graph I. (If any degradation occurs
during isolation then I like to have it in the desired direction rather than RSP plus POP direction)--In any case, the whole
thing will be over by the end of this week. The other experiments we want to do this week are to test RIS-dip-ui[?] the system
and also to put degradation products of PRPP on a paper chromatogram and identify the R-diphosphate is the 'cycle',
Now that at long last the end is in sight, it would be nice to write it up. (The [. . .] catalysis of degradation was of
especial interest to nucleotide coenzymes). I would like to know from you whether you definitely want me to be in St. Louis
before [. . .] meetings. I am going to be rather rushed that week but will try to get there just the same.
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I am planning to leave here on April 2 and will be finished with talks in Ontario by April 8 then expect to be in Boston area
for a couple of days. I like to visit Bob Chambers for a day after that but this may have to be omitted (we still have to
write up a part of Bob's work, which John has continued).
There is also the possibility of my staying over in the East after Fed[?] meetings and so, please just say when it is convenient
Roy Markham is expected to be here for the summer and we are looking forward to having him here. I am definitely planning
to have done with writing before then, so that I can work with Roy on oligonucleotides.
This pretty well covers my end of the story. With best regards and greetings from all of us.