March 25, 1948.

Dr. Fdna «. Montgomery,

Corn Industries Research Foundation,
825 North University,

Peoria 5, Ulinois.

Dear Dr. Montgomery,

Thank you for your offer of samples of isomaltose. While my previous requests
mentioned quantities of the order of 10 ag, your letter left the impression that
in consequence of your chemleal work, ach larger quantities might be readily
available. Individual strains can be tested on 10 mg each, but a more satisfactory
somcarativs series would require 200 mg. Since I do dot know how difficult isomaltose
_is to prepare now, I must leave it to your judgment how large a sample it would
be worthwhile using up.

Rs, Stodola my have mentioned that we are working on changes in carbohydrase
specifities brought about by genetic mitations in Escherichia coli. For the moat
part we are stpdying lactose- and maltose- splitting enzymes, aod at least for the
former have considerable evidence of "indirect" (initial hydrolysis) fermentation.
While some mutants aopear to have lost all ealactosidutie activity, others wiil
split methyl galactoslde but not lactose. We are therefore looking for other sub-
strates which may allow a further olassification of the specificities of the mutant
enzymes. While Dr. K. P. Link is cooperating in these studdes in the synthesis of
likely substrates, we could not hope to preppre anew every compound that might be
useful. Therefore, I am trying to obtain by gift sufficient samples (200 mg if pos-
sible) of these analogs to make &@ preliminary determination of their usefulness
in the program. I have already corresponded with Pigman and with Richtmyer for
the initial sample of methyl b-D-galactoside and neolactose respectively. I suspect
that you could as easily suggest as I the kind of compound worth trying. I hawin
mind other b-D-gelactosides, particularly epimers of lactose, iuctosides, lactositol,
and other alkyl or aryl derivatives, on the one hand, and related glycosides such
as s-lL-arebinosides, desoxygaiactosides, b-D-fucosides, ete. I should be grateful
to have any of these or like commounds.

Galactosan (1,6-anhydro-b-D-pyranose) is ancther galastoside in which we may
have a common interest. In view of our departmental chairman, 2...Erink's, early
work, we are interested in waxy starch, and I was particularly interested in your
receht description of levoglucosan in waxy atemeh hydrolysates. is Peat points out,
anhydro sugars my play an important biological role, but so far as I know their
biologics] availebllity has never heen tested. I should be glad to test eny of
these compands(on various coli mutants) that you might care to send. A recently isolated
mutant which uses both softies of maitose, but not glucose, might be particularly
cogent.

Yours sincerely,

Joshua Lederberg
Assistant Professor of Genetics.