VETERANS ADMINISTRATION

HOSPITAL
ALBANY, NEw YorRK

February 17, 1960

 

YOUR FILE REFERENCE:

IN REPLY REFER TO: 5247/172
- Dr, Joshua Lederberg
Department of Genetics
Stanford University
Stanford, California

Dear Josh:

Thank you for the strains you sent me some time ago, the Lac ~ #4324
and the Gal Lace #4349, The former did not turn out to Be
glucose-perfiease Régative as expected, As a matter of fact, it

has also all three permeases, the galactose, Monod's, and MG's
permease, Mutant #4349 was a lot more interesting because in it

we were able to test for the first time the galactose-permease in

the absence of B-galactosidase and other permeases, It called to

my attention the fact that so far all Gal strains we have tested
have been MG-permease negative.and It could be that the MG~permease
is closely associated with galactokinase, if not galactokinase itself,
Gale (#3108), another galactokinase-negative was also MG-permease
negative, A revertant of #4349, in which ability to utilize galactose
was restored, did not have the MG=permease, This could be considered
a strike against the hypothesis although I have to test yet this
reverted mutant after galactose-induction,

I have read in Kurahashi's paper that you have another strain which
is galactokinase negative, W-3142, which is not linked to the other
Gal loci, I would appreciate it very much if you could send me

/ this strain to test it for MG~permease and see if it fits the
picture,

Rather than telling you about my other results I will send you soon a
manuscript on the specificity and relationship of all the galactose
and galactoside permeases known at this time,

With best regards to Esther and you,
Yours,
Boris Rotman

P,S, Your hypothesis about galactose being a constitutive inducer
of the permease seem less likely at this point, Mutant #3099 which,
according to Kalckar, does not make internal galactose from glucose

does have a galactose~permease,

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