February 6, 1961

Or. Frank Mayo
Stanford Research Institute
Menlo Park, California

Dear Frank:

It was a pleasure to talk to you the other day end hope we can continue
to get together about this problem of specific polymer synthesis. One
point | should have pressed you further one was the possibility of
Improving the sensitivity of analysis to allow the detection of very small
proportions of the specific product. If you did this along the lines
that would be routine In the Blochemistry Department here, you would use
clhelabeled acrylate In the precursor mix and look for radicactivity In
the tricarboxylic acid fraction of the product on a paper chromatogram.
tf necessary of course, you could add cold tricarboxylate as carrier.

How sensitive Is your present technique, thet is, what proportion of the
monimer would have to be specifically converted for you to pick It up.

May | ask you a slightly different question? Whipple thinks that
comets are composed mainly of frozen ‘‘ices'' of methane and some other
hydrides. How efficiently would such an ice be polymerized when exposed
to very short wavelength solar UV at temperatures of between 10 and 50° K.

Yours cordlaily,

Joshua Lederberg
Professor of Genetics

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