May 25, 1953

Dr. Boris Rotman
1003 Grove 3treet
Evanston, Illinois

Dear Boris:

I have your letter of May 21, and have discussed it with Dr. Lardy.

Wesare both very pleased indeed, on your behalf,at your offered professor-
ship at Santlago, and wish you every success in it,

I have to tell you that this curtailment of your free time will make some
difference in our own plans, but only that we could not encourage you to
continue to work on your yeast problems. In view of the limitation of time,
we feel that it would be imperative for you to begin at once on a problem of
mutual interest (Lardy, you and myself), rather than to wait for this to develop.
The problem aust also be sufficiently circumscribed that you could attack it
at once, ald have some hope of significant progress in the few mohths. I have
discussed one such problem with Lardy, namely the question of the nature of
the difference in kinetics and activity of galactosidase dadintact cells of
E. coli K-12, and in extracts. As you know, disruption of the bacteria causes
not only about 25=fold increase in activity, but also "exposes" the enzyme so
that ita activity can be i@fluenced by changes in pH and ion concentration. It
4s not certain whether this is, as it appears superficially to be, a permeability
effect, and if so whether it is the substrate or the activating cations that are
principally involved. If it is a permeability mechaniam, this is axceptionally

favorable material for studying this mooted question in relation to enzymatic
activity of intact cells.

In continnigg this discussion, I am assuming that you will be able to postpone
your acceptance of the position in Chile until April. The only obstacle to our
formally offering a fellowship here 4s that we have to wait for Congresa to
act on the appropriation. I underatand that our chances are excellent (or I
would not be able to write you). As to this summr, the appointment could begin
July 1 (if the money is available). Things will be rather cramped in my lab.
but I think we can accomodate you until space is made at the Enzyme Institute,
especially for the preliminary experiments along the above lines, which would
not be very demanding. ‘The stipend would be the same as for the PHS Fellowships
($3000 or more if a dependent is shown). Does this arrangement suit you? If
you have any alternative suggestions, please let me know.

I happen to know of a room very close to campus that will be vacant this summer.
You can ask E.S. Anderson about it if you see him at CSH. If you would like me
to try to reserve it for you, either for the summer or for longer please let me
know, along with any other plans that may be relevant.

With best wishes,

Joshua Lederberg