REHOVOTH «IS
P.0.B. 26 »‘PHONE:2

O gFBo,

“40

LES
sit yon yoo

THE WEIZMANN INSTITUTE OF SCIENCE

RAEL Seiw?. yarn

+
$9, 301 301,259 :;1STD + 2 xt

‘Sth February, 1956

Prof, Joshua Lederberg
Department of Genetics
University of Wisconsin
MADISON 6, Wisc.

Dear Dr. Lederberg,

I would like to thank you again for the
culture of E.coli K~12 serineless mutant, which enabled us to
establish unequivocally the appearance of serine upon alkaline
incubation of iodinated polytyrosine,

In connection with a study of the digestion
of peotides and polymers containing proline, by various micro-
organisms, I would be very grateful to you if 7rou would be as kind
as to send me a culture of E.coli K-12 prolineless mutant strain

679-183»

I am really sorry to trouble you with
this request, but I hope that it will again enable us to elucidate
some facts of interest,

Thanking you in advance,

Cordially yours,

4 “ay R i § ar} of

Sarah Sarid