January 27, 1948.
Dr. Frank Stodola,
Fermentation Division,
Northern fegional Research Laboratory,
Peoria, Illinois.
Year Frank,

It's allittle strange that our interests should be converging again after
all these years, but so itsis, and the point of convergence is the mechanism
of disaccharide utilization, and in particular the bionic acids.

The genetic study of E, coli disacchhrases has reached the point that there
ie either a complexmechamiam of lactose utilization, or the postulate of

one gene : one enzyme is fallacious. If both these ideas were verified, I
shouldn't beaat all surprised.

One of the supposedly lactose-negative mutants proved to be unable to
assimilate any of the natural hexoses and di-hexoses, but utilized gluconic
acid and the pentoses well. At the same time, I have been unable to demon-
strate any lactose- or maltose~ splitting activity in the mutant, waing other
mutants which could utilize monoses but dot the diosew for assay. This suggested
that the first hypothesis that has to be tested is that the first step in the
utilization of dieses by E. coli might be oxidation to the bionic acid. Looking
through the literature, I found your paper in JBC 171:213 (Nov. '47) where you
and Lockwood reached a not very different conclusion. The yields that you re-
ported were so high that you must have a fair quaniity of fairly pure malto-
bionic and lactobionic acid. If you could spare a few prams of each, 1 »ould
greatly appreciate it. To be usable, the prep. would have to be not too heavily

loaded with the original sugaej and be substantially free of hexonic ac.
Along the same lines, I would be glad to get my hands on g-ketoglu8onic
and on d-xylonic acid. Can you suggest any better source than yourself, or your
laboratory. Finally, don't you think we ought to trade places on mailing lists?

Thanks for the “hristmas picture-card. I'd like to get to see you in

again
person and meet your family, but the Fites haven't called that card yet.

Yours sincerely,

Joshua Lederberg