Department of Genetics

December 25, 1958

Professor Hugo Theorell
Karolinska Institutet
Stockholm 60, Swedeb

Dear Professor Theorell:

| am sure | do not have to recapitulate the appreciation of a Nobel
laureate for the consideration and hospitality of his colleague: during
an occasion like that of this past month's. My wide and | are deeply grateful.

Our discussion of enzyme structure was also most Illuminating, and |
was delighted to hear of your analyses of amino acid sequence in cytochromes.
May | remind you of my request for reprints of the relevant papers?

t am enclosing a primitive paper of my own on some aspects of the kinetiés
cf the B-Pegalectosidase of Escherichia coll. In fact, Steve Kuby whe was

working in your laboratory last year followed this up in much more detail N
in: J. Am. Chem. Soc., 75, 890, 1953. 1 am sure that this enzyme deserves t
as much attention from physical chemical approaches as it has had in physio- «
logical genetics. Now that it has been crystallized, and with the accessibility x,
of machinery for growing large masses of the bacteria (which contain 1-2 pe. re
of this enzyme under suitable conditions) one might hope to find renewed interest >

in It. The cation effects are among the intriguing aspects. “

The chromogenic substrate can be readily purchased @ from the 'Mann Research L
Labs., 136 Liberty Street, New York 6, N.Y.'' at $20 per gram, which goes a very ~
long way. .

Yours sincerely,

Joshua Lederberg