May 28, 1958

Dear Herman:

Very interesting: It is more important than ever that we should transduce
Gal,” into a constitutiveelactase mitant, to see if the epimerase block also
prevents the formation of the presumed powerful internal inducer in the
Constitutive strain,

But there are seme other odd features about your figures, though I have to
try to translate from your arbitrary galactodidase units into units I am more
familiar with. Ca: you just tell me what the relative activity of W=3100 would
be if grown on lactose?

I would not suppose this would be very much hicrher than you get with galactose,
If so, then Gal,~ becomes a fullefledged lactase-constitutive (i.e. you get
4500 unite on just glycerol). Of course we have other lactase-conatitutives which
are not, galactoseenegative, Wien we get the Gal,” combination, we will send you
the Gal original for comparison, of course, *

We have been somewhat preoccupied with developing methods for napping the
order of the different Gal genes. We have considerable encouragement on this
point, and hope to be able to see, in due course, whether the kinase and trans~
ferase cistrons fall into two distinct mapping intervals, and where, in reletion
to them we will find Gals, Galo ete.

Keer in touch,

Yours,

 

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