Kornberg had earlier requested information from G. A. LePage about his new method for preparing TPN (triphosphopyridine nucleotide),
but the product he made using the method was not satisfactory. In this letter, LePage discussed possible reasons for Kornberg's
problems with the process.
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2 (113,113 Bytes)
1949-11-30 (November 30, 1949)
LePage, G. A.
University of Wisconsin. School of Medicine
Original Repository: Stanford University Libraries. Department of Special Collections and University Archives. Arthur Kornberg Papers
Reproduced with permission of the University of Wisconsin Medical School.
Medical Subject Headings (MeSH):
From Physician to Enzyme Hunter, 1942-1953
November 30, 1949
Dear Dr. Kornberg:
I received your letter of November 15. Like you, I am at a loss to understand our discrepancies in phosphate analyses. The
preparation we sent you analyzed 97% with glucose-6-phosphate dehydrogenase on our first assay, uncorrected for water. Dr.
Mueller suggested a check and a second watching which was very stingy (2.5 mg. on ordinary analytical balance) gave an assay
of 115%. We thought the first assay was probably correct and sent the preparation on, since you would assay it anyhow.
After some 10 days, we found, as you did, a lower assay (69, 73%). I find 11.5% phosphorus. We reassayed it later and the
material seemed to have stabilized at 70%. But now it has material in it which causes the hydrosulfite assay to be much higher
than the enzyme assay. Yesterday I finally found time to run the material on a chromatogram. Using a batch of charcoal which
has always given essentially complete recoveries with other preparations, I obtained only 40% recovery. This seems to confirm
the suggestion that it is contaminated with metals and makes further work with this particular batch useless.
At present I have no need for TPN in my own research and Dr. Mueller has finished the work in which he required it. I am
engaged in two problems which involve collaboration with other members of our staff. Pressure from them to get on with our
collaborative work makes it difficult to justify taking time out just now to start another batch of TPN. I very much regret
it, but feel I must leave this matter up to you now. I note that you stated in your earlier letters that you were really
satisfied -- the results obtained on your own preparations were valid, that they are free of phosphorus bearing contaminants.
May I suggest you go ahead with your publication. We would prefer you omit any consideration of our help unless you wish
to comment on receipt of' our manuscript before publication.
It is worth noting that this instability of TPN when trace metals are present is not confined to TPN. Sclilenk found that
DPN preparations containing traces of aluminum from alumina columns exhibit similar instability. We have had preparations
around long enough to be certain this instability is not found routinely. It is observable in another old sample I have left,
but this too was contaminated (Hg) with trace metal. Impure preparations must contain some protective factor, since our impure
preparations made via the Warburg technique were quite stable.
We shall look forward to seeing your unraveling of the TPN structure.